Wednesday, February 24, 2010

Singletrack, Chukars, and a Really Long Tangent About First Class

When I got the helmet-cam I didn’t really didn’t think much about how I’d use it. Oh, I expected I’d email videos to friends and post some on the blog, but what I didn’t anticipate is how much I’d enjoy watching the videos. That sounds dumb. After all I was on the ride- why do I need a video of it? But when I’m away for work in some hotel room or stuck on a long flight (like right now) and feeling penned-up, it’s remarkable how weirdly liberating/ escapist it is to “re-live” the ride.

Tangent: This one is long and bizarre, but culminates in a great half-baked conspiracy theory, so stick with it.

I guess this flight isn’t all that bad, as I’m sitting in first class. I fly often enough that I get upgraded on domestic flights about half the time. I’ve always found the whole coach/first class thing to be kind of weird. When you think about it, we live our whole lives in a world carved up by socio-economic divisions. Yes of course there’s the whole first world-third world thing, but I’m talking on a smaller scale. Every metro area has class divisions in it’s neighborhoods/suburbs, and these divisions are evident in homes, roads, shopping mall anchor-stores, signage (billboards), even the type and condition of playground equipment in public parks. And within neighborhoods, there’s another mini-class-tiering at play in the schools which the neighborhood children attend.

Extra Detail: In my East Side* neighborhood, there are probably 4 distinct schooling classes. 1st is Rowland Hall-St. Mark’s (Episcopal private school- way snooty.) 2nd is other private schools, such as McGillis (affiliated with Jewish Community Center.) Third is kids who go to out-of-zone public schools. We’re in this category- our kids, and several others in the neighborhood attend an out-of-zone public school to which we applied due to its strong academic reputation. Catholic schools probably also fit in this class. Fourth would be the school we are actually zoned for.

*BTW, have you noticed that in inland US cities situated alongside mountain ranges, the higher-end neighborhoods are always on the mountain-side of downtown? Salt Lake, Denver and Albuquerque are 3 big examples, but the rule holds for smaller cities as well, such as Ogden, Provo, Boulder and Fort Collins.

The funny thing is, all of these schools are actually quite good. Oh sure, there are differences in class size and such, but I’m pretty sure a reasonably bright kid from a decent home would thrive in any of them.

Extra Extra Detail: There’s a another dynamic in our neighborhood school class divisions, one that is at play in neighborhoods all along the Wasatch Front, which someday, in another post, I may blog about more fully, and that is the church issue. In Utah, non-Mormons routinely make public-private school decisions in large part due to the perception- rightly or wrongly- that the public schools are the Mormon schools, in which their children may experience, in some way, a minority status, or be somehow left out socially. I’ve never noticed this in other states, but in Utah it’s a fairly standard school-choice consideration among non-Mormons.

Though I generally scoff at such small-mindedness, I have to admit that among the reasons we selected the (public) school we did for the Trifecta was the “diversity” of the student body. And in Utah, much of the time, “diverse” is a thinly-veiled code-word for “not Mormon.”

And then you get on an airplane, for just a few hours, and there it is again: the wide comfortable seats of first class in front, and the cramped human-cargo aka “coach” class stuffed in back. As a frequent flier I’m of course glad for the space, but the closet-socialist in me is perpetually offended. Why can’t- instead of a few really great seats and a whole bunch of really crappy seats- why can’t we all have decent seats. Would that be so bad? Yeah, yeah, free markets, supply and demand, invisible hand of my economics professor, blah, blah- I get it already. But really, it’s just a few hours- it’s not like we’ll all turn into Marxists or Canadians or something. Couldn’t we all just have OK/tolerable (non-reclining) seats and be happy with it?

Of course, as any frequent flier knows, first class isn’t what it used to be. There’s no real meal* on any flight under 4 or 5 hours, no more ice cream sundaes, and the warm, moist pre-dinner cloth seems to have disappeared over the last year or so**.

Basket *Now, on any flight under 4 hours, they just serve the same crappy snacks- peanuts, pretzels and “biscott (WTF?) cookies”- as they do back in coach, but in first class they serve them in a special wicker basket. Seriously, the flight attendant will come up and present this basket full of crap with this theatrical flourish, as if she’s offering you beluga caviar or something.

**Which was fine by me. I never really knew what to do with the towel anyway. The presentation of it would always guilt me into a sort of Potemkin-“washing” of my hands, something I never do when seated at a normal restaurant. Some guys would wipe their faces with a big relaxing sigh, as if they’d just stepped into the shower and which I always found a bit weird. (You’re in public, what are you- washing your face? Hey, don’t let me stop you- get behind the ears!)

Nowadays, the only redeeming features of first class are wide seats, and friendly flight attendants. Curtain Seriously, up here the flight attendants are all smiley, helpful and re-affirming. But walk past the coach-curtain*, and it’s like Dr. Jekyll – Mr. Hyde; they get all snarly and reprimand-y.

*Oh yeah, that curtain. Don’t you love that? It’s like we high-class people don’t even want you little people looking at us…

Nested Tangent: Is it just me, or are flight attendants getting older? When I started flying, ~20 years ago, flight attendants were all like 25. On tonight’s flight the lady pouring me coffee looks like she fought in the Spanish-American War.

It’s almost as though the only really worthwhile thing about first class left is that it’s not coach. And this leads to my brilliant half-baked conspiracy theory, which is that several years back the airlines decided to give up on trying to make first class better, they could just make it seem better far more easily and cost-effectively simply by making coach suck more.

Woo. That was long- almost forgot I had a post. Anyway, here’s a clip from early last Friday morning, just before a small storm blew in.

The Video Already

IMG_4352 Couple of notes, mostly for non-local readers. This is the lower part of the descent from the antenna towers North of downtown Salt Lake. At 0:13 I pass a real nice magpie nest in the scrub oak on the right. At 1:06 you see my front tire pop into view as I wheelie over the curb and onto the singletrack, which immediately turns to the right/North, at which point you can see the refineries of North Salt Lake in the upper left of the screen. After the switchback I’m generally heading South. At about 2:00, downtown comes into view; the state capitol is on the left, the tall white building in the center is the LDS church HQ. The snow-covered mountains appearing to the left of downtown are the Wasatch range; the peak at the apparent right end of the range, just to the left of the capitol, is 11,253 ft. Lone Peak.

At 2:15 a chukar flies across the trail. We’ll come back to this guy in a moment.

Most of the homes along this stretch BTW, didn’t exist when I moved here in ‘95. It’s sort of bizarre in that they’re pretty pricey houses, but basically look down on refineries, rail-yards and a freeway, and experience a fair amount of noise as a result. Sunsets are nice though.

At 3:19, downtown returns to view, now much closer, and to the immediate right of the church HQ tower you can see the LDS temple, a lower-height white building with several spires, silhouetted against the darker mid-level office building behind.

So, back to the chukar. They’re not unusual around here; I always seem to see them when up around Antelope Island. But it turns out there’s something kind of interesting about them here in Utah, and the Intermountain West in general.

chukar2 Chukars, Alectoris chukar, (pic right, not mine) are native to Eurasia, but have been deliberately introduced to the Western US as game-birds, multiple times, starting in the 1890’s. They’re partridges, which belong to the pheasant family, Phasiandae. As a rule, partridges are medium-sized birds, bigger than quail, but smaller than pheasants. Chukars are considered more challenging game than pheasants or quail because they’re faster flyers*.

*Just to be clear- this isn’t the interesting thing; I’m just laying the groundwork here…

Phasiandae in turn is part of the order Galliformes, or landfowl, which in turn is part of the superorder Galloanserae, or “fowl,” which in turn brings up something I keep meaning to get around to, but haven’t, so I’m just going to do it now.

Here in Utah- or anywhere in North America for that matter- all of the birds you see fall into 2 groups, or superorders. The first, Galloanserae, are all of the pheasants, ducks, geese, swans, chickens, turkeys, grouse, quail, etc. The second superorder, Neoaves, includes every other bird you see- pigeons, crows, finches, hawks- you name it, they’re all descended from a common ancestor. So when you see a duck or a grouse or a chukar, you’re looking at a sort of “other” bird, that hasn’t shared a common ancestor with all those “regular” birds since there were dinosaurs walking around. They’re kind of like the marsupials of the bird-world.

Side Note: Actually, there are significantly more “otherly” birds in the world, more deserving of the marsupial comparison. Neoaves and Galloanserae together form an “infraclass” called Neognathae, which includes all living birds except for ratites (ostriches, emus, rheas, etc.) and tinamous, which belong to a sister infraclass called Paleognathae, and have significantly different anatomical features including jaw, metacarpals and vertebrae. But since here in the US you’re only likely to see paleognaths in a zoo or aviary, a “fowl” is about as “other-ish” a bird as you’re likely to see out and about*.

*No, this isn’t the interesting thing either- I’m getting to it already…

Bird Phylog Additionally, paleontologists believe that there were other more distantly-related, or more basal, orders of birds way back when, all of which are today extinct*.

*Nope, still not the interesting thing.

So chukars are pretty common in Utah. Like pigeons, starlings and house sparrows, they’re exotics, but unlike those birds, their North American range is largely restricted to the Intermountain West. Why?*

*OK, this is the interesting part.

CedarMtnCheatgrass5 Guess what chukars’ favorite food is? Bromus tectorum, or cheatgrass (pic left) seeds. Those same, annoying little seeds that get stuck in your socks. That's right- chukars thrive on exactly the exotic grass that’s pretty much taken over the Great Basin, starting in the 1880’s. We’ve looked at cheatgrass before; it does so well here* in part because it grows and seeds earlier in the season than native grasses. Though B. tectorum now occurs in all 50 states, the Intermountain West has the the most extensive/ densest “cheatgrasslands.”

*Cool factoid: botanists believe that the cheatgrass in the American West today is the result of 7 or 8 separate introductions.

So how fortuitous (for chukars) is that? We settle North America, and subsequently accidently introduce cheatgrass, which pretty much takes over the Great Basin. Then a mere decade or two later we release a bird that loves cheatgrass. From the perspective of the bird, it’s as if someone captured it and then released it in place that’s almost like Heaven (with the obvious exception of all those guys trying to shoot it, I guess.)

I don’t ride the antenna-hills trails all that often, usually only in winter or early spring. It’s mostly South-facing and open, and so melts out faster than most other trails in the foothills. Riding here now is only possible early in the morning, ideally around dawn, while everything is frozen hard. And if you oversleep, and start your ride too late, as I did Sunday morning, well, you might be OK on the way up, but on the way back down… well, that’s a whole other deal, and a whole other post.

Next Up: What is the deal with clay?

Friday, February 19, 2010

Catch-Up: Features, Blogroll & Graphics Re-Use

Time for some catch-up, including RSS feed, blog-roll updates and use of WTWWU graphics.

First Thing- RSS Feed

I’ve added an RSS feed for any readers who’d like to be kept abreast of comments. Thanks SkiBikeJunkie for the suggestion and how-to. Since many regular readers frequently post helpful and insightful comments, hopefully this feature will come in handy to some number of you.

Tangent: Though strangely, as I’ve mentioned before, many of the comments I get are “direct”, the foremost example being my Legion of Lurking Coworker Readers who regularly walk over to my office to comment on, question or critique a post. Every once in a while one of them will say something thoughtful or insightful, and I’ll say something like, “Hey, that’s really thoughtful or insightful. You should post a comment.” And then they’ll get all nervous and weird and laugh uneasily, like I just invited them to a swinger’s get-together or an Amway meeting. (Really, it’s just a blog. Only like 300* people a day read it. You can post a comment- no one will make fun of you.)

*On a good day, when I post cool graphics and Selma Hayek photos.

wwwlogo3[5] The Legion was/is also weird about WatcherSTICKERS. When I came out with them, about a dozen Legionnaires stopped by my office, asking for one, which I was happy to provide. So far as I can tell, none of these stickers has actually been applied to a surface of any sort. Several are thumb-tacked to cubicle-walls, and one coworker keeps his in the console-CD-cubby hole in his car below, the dashboard. “My wife won’t let me put a bumpersticker on the car…” he explained*…

*Seriously- how short is your leash?

A fair number of real-world friends/associates have asked for a sticker, but qualified it with, “I don’t put anything on my car…” in sort of a hushed, embarrassed tone, as if by giving them the sticker I were implying something scandalous. Just to be clear- if you have a sticker, I don’t care where you apply it, and second, it’s a sticker. Putting a sticker on your car or snowboard or rooftop-rocket-box is just that- a sticker. It’s not like getting a tattoo on your buttock or piercing your nipple. If you change your mind you can peel it off. And really, what’s with all these clean car people anyway? What are they, planning to deliver a baby on the hood or something?

Second Thing- Blogroll Updates

It’s been a while since I updated the blogroll. I try not to keep too long a blogroll because a) I like to keep it to blogs I regularly read, and b) if it gets too long I don’t think it’s all that helpful to readers. But I’ve been reading some good blogs lately and have added a few. Some are informative; some are just fun.

michelle RWoods First is Rambling Woods, which is foremost an excellent birding blog, but also covers a wide range of butterflies, moths, mammals and more. Michelle, the author is based in Western NY state and had a middle-aged awakening 6 years ago when she became curious about a hawk that landed on the railing or her deck. She’s kicked it into high gear ever since, and following along you can share in her wonderful observations and discoveries.

marcia-b-holding-eagle-katz Speaking of great writing, Marcia Bonta is a naturalist, the author of 9 books and hundreds of magazine articles located in central Pennsylvania. Her blog includes postings from her regular column “Naturalist’s Eye” from Pennsylvania Game News*. She covers all sorts of wonderful topics, and I absolutely loved her recent Eastern White Pine post.

*I’m dying to work this into a conversation. I have it all mapped out in my head. I’ll be talking with someone and drop some little factoid, and they’ll be like, “Really? Where’d you hear that?” and I’ll be like, “Really, it’s true! I read in Pennsylvania Game News!”

Desert Survivor and Desert Boy Next up is Desert Survivor, which I’ve actually been reading for over a year, and which replaces A Plant A Day on the roll. (DS is her primary blog, APAD was an additional blog that I followed daily last summer, but appears to have gone into winter hiatus/dormancy.) This one takes some explaining.

About 30-50% of the time, DS reads like, well, a Mommy-Blog*. Now, I have absolutely nothing against Mommy-Blogs, but I don’t generally read them*. But Desert Survivor is also part naturalist, part caver, part rancher-blog**. I follow it for all of these topics, but probably most of all because it is one of my half-assed fantasies is to live in East-central Nevada***. DS’s blog is filled with enough photos and info to pretty quickly figure out the “town” where she and her family resides, and it’s one of my favorite parts of the state.

*Yes, I love kids. Had 3. That was enough.

**Coincidentally, the Dooce lady lives about 4 blocks from me. No, I don’t know her, but everyone in the ‘hood knows who she is. The Mommy-blog phenomenon falls in the same life-experience category for me as TV Reality Shows, cruises, spectator sports, and golf: something that is obviously wildly popular among millions of people, but which I totally Do Not Get. This Do-Not-Get category is a life-long head-scratcher for me. Sometimes, late at night, I wonder if I’m really human, or in fact some kind of alien-deployed doppelganger/android, and the Do-Not-Get category reflects a range of topics which my Secret Alien Masters neglected to program into my cognition/ awareness module.

***Note for AW, who will inevitably read this: No, no, no- don’t call the divorce lawyer; I’m not cooking up a scheme to move us out to Nevada. It’s just a fantasy, like being an astronaut, or a rock star, or that time I asked you to speak with a Mexican accent and pretend to be Selma Hayek****.

****Totally, totally kidding.

Pie Queen Closer to home, I’ve added Jube/Lucy’s blog, Married with Bikes. Lucy is another Salt Lake mountain biker who blogs about all sorts of things, but my absolute favorite posts are when she writes about her work. She’s a hydrogeologist working for the state of Utah, and knows all sorts of cool stuff about local geology and hydrology. She’s involved in assessing water flows, tables and sources in the Snake River Valley (focus of a highly-controversial project to suck the very life and soul out of a stunning rural valley to construct a water pipeline to Las Vegas.)

Tangent: But none of this is the remarkable thing about Lucy’s blog. No, the truly remarkable thing about MWB is that isn’t technically her blog; it’s hers and her husband’s (aka Drew) blog. They alternate posting, always doing do in a relentlessly upbeat and cheerful tone, neither one ever making so much as a snarky wise-crack about the other. Now I know many readers, like me, have blogs of their own. Seriously- can you imagine co-authoring a blog with your spouse? AW would kill me with a kitchen utensil within a week*. How do they do it? Is it a newlywed deal, is there some kind of Stepford thing at work? (In all seriousness, the 2 of them are some of the nicest people you’ll ever meet.)

*Yes, yes, I know what you’re thinking: “But that’s because your blog is so freaking weird…” OK, so maybe that might accelerate the inevitable homicide, but I still think- even for normal people- that co-authoring a blog with one’s spouse would be tough.

dug planet of apes hat Lastly is SuncrestDug, another local biker/skier who also lives nearby, specifically up on (wait for it… wait for it..) Suncrest. I don’t know Dug in real life, but we have a couple of friends in common, and I expect sometime we’ll meet. (Pulled this photo off his blog. I totally love the hat; it makes him look like one of those telepath-guys in the 2nd Planet of the Apes movie who lived underground and worshipped the atom bomb.) In the meantime I regularly enjoy his blog for the writing, humor and social/human observations. Something that’s difficult to convey to out-of-staters about Utah is that there are a lot of funny things about living here that you can’t get really get unless you live here. I can’t explain it any better than that, other than to say that Dug routinely highlights and nails these things in his blog.

Third Thing – Graphics Re-Use Permission

You got it. Seriously, it’s fine to re-use them.

From time to time I’ll get a comment on an old post, and a good many of these old-post-comments are asking policy/permission to use graphics.

Tangent: Sadly, these requests are inevitably to use “serious” graphics, such as this, this, or this, and never my favorite graphics, such as this, this, or this*. One of my secret fantasies is that I’m walking down some city street someday and pass someone wearing a T-Shirt with one of my graphics on it**.

*Or this, this, this, this, this, this, this, this or this. Seriously, how awesome are my graphics? I wish there were some kind of blog-award for graphics; I would totally win it.

**In my secretest fantasy, it turns out to be Selma Hayek wearing the T-shirt.

So here’s my policy: go for it. Feel free to use any graphic or photo- of mine- that appears in this blog. Note that I often include photos that are not mine, and try to clearly mark/link such photos when I do so. But any graphic or photo that’s mine, you’re welcome to use.

If you do so, it would be nice if you gave source-credit to this blog. Though this is a completely non-commercial venture, I spend a fair amount of time and effort creating these graphics, and I’d appreciate the acknowledgement. But if you forget, space or simply blow off doing so, no worries; I won’t sue you or send you snarky emails. You’ll just be filled with a general ill-at-ease, bad-karma vibe that will slowly eat away at you, disrupt your sleep, undermine your social, professional and family relationships, and ultimately completely and utterly destroy everything you value in this life, turning you into a sad, lonely, friendless empty husk of a person. But really, no worries.

Tuesday, February 16, 2010

Pigeon Week Part 3: Peregrine Attacks, Plumage and Feral Future

When you think “pigeon”, you probably have an image in your head that looks something like this: dark head and neck, light gray breast and belly, black-tipped tail, and 2 black stripes on each wing. But if you slow down a bit and check out a group of pigeons around town, you’ll notice that many look quite different.

The “standard” type I described above is a called a Blue-bar, even though the bars on its wings aren’t blue, and it’s closest in coloration to wild rock pigeons. Another very common color pattern is called the Blue Checker. At first glance they appear similar to Blue-bars, but their wing bars are generally a bit wider, and the feathers between bars and neck are spotted with black “checks.” You’ll also notice that some pigeons are very dark, almost a black slate color except for more metallic-y looking feathers on the neck, and this pattern is called Spread.

Plumage Types1 Every once in a while you’ll see a white pigeon. Though a few white pigeons are true albinos, most are not; they’re just colored white, and their non-albinism is almost always belied by a few spots of darker color. Another noticeable pattern is pigeons that have spots of white in key locations only, such as the head, or wing-tips, and this pattern is called Pied. Yet other pigeons have red or reddish-brown feathers, and depending on the distribution of such feathers, some of these are known as Red or Red-bar.

So there are a number of basic color patterns among pigeons, with many subtle gradations between the basic types, and therefore unlike almost all of the other wild animals we see daily around town- magpies, crows, starlings, mule deer, squirrels, raccoons- individual pigeons are fairly easy to tell apart.

Tangent: In fact, over the 2 weeks that I’ve been observing and photographing my favorite flock at the strip mall on the NW corner of 1300 East and 8600 South, IMG_4312I’ve actually come to recognized several individuals, and noticed that they almost always perch at the exact same location. This White (pic right) for instance, is always just under the West-facing eave atop of the Indian/Chinese restaurant building. The Pied pictured below is on the East side of the roof across the lot, the Northernmost of the 2 pigeons perched there. Seriously, if you live in Salt Lake Valley and you drive over there right now, I’ll bet money that’s exactly where they’ll be.

So while it’s nice that they’re easy to tell apart, it raises an interesting question: why so many colors/color patterns? Wild pigeons, true wild Columba livia, from the Old World, are basically all Blue-bars. The pigeons we see are feral pigeons, meaning that they’re descended from domestic pigeons who at some point escaped captivity. Human breeders have bred pigeons for many characteristics, including color, so it’s easy to see where feral pigeons got their color: from their domesticated ancestors.

Pied TypeBut that doesn’t explain why they’ve kept their colors. Most feral animal populations, after successive generations, tend toward a similar coloration pattern. One might argue that not enough time has passed for colors to “average out”, but feral pigeons have been thriving in North America for hundreds of generations, and in the Old World for thousands. The answer isn’t obvious. A number of raptors hunt pigeons, and in the wild animals with unusual coloration tend to be singled out of a flock or pack more often by predators. So why don’t modern feral pigeons look more alike?

There are some trends in pattern and coloration. In Eurasia, the farther North you go between about 40 and 60 degrees in latitude, the darker feral pigeons tend to be. The trend is too high for chance*but it’s not clear what the Northern selection pressure for darker pigeons is.

*Specifically 21 locations sample between 41N and 62N, showing a correlation coefficient of r = 0.75.

Another trend is that urban populations seem to show more color variety- and specifically more whites- than rural, “wild”-living feral populations. It’s suspected that the relative dearth of traditional raptor-predators in many urban areas may ease selection pressure toward wild-type coloration, and non blue-bar color-patterns (think Checker or Spread) may even have advantages against other urban-specific threats, such as humans, dogs and cats.

WhiteRump1 While the possible benefits and liabilities of all color patterns under all conditions aren’t known, the benefit of at least one pattern is. Many feral pigeons- and many truly wild pigeons- have a distinctive white patch on their lower backs, just above the tail. When the pigeon is on the ground, the patch is mostly covered by the folded wings and not easy to see (pic left). But if you catch a glimpse of a pigeon flying away from you, it’s immediately obvious (pic below, left).

peregrine-falcon-2-18-05-mi Over a 7 year period, researchers observed several flocks of feral pigeons, numbering roughly 5,000 total, in the Davis, California area, roughly 23% of whom had this white patch. During this time they witnessed nearly 1500 attacks on these pigeons by 5 Peregrine Falcons (pic right, not mine) in the area, 3 of whom were still juveniles when the study began. Peregrines are regular and highly effective predators of pigeons, swooping down from above and behind and capturing them in mid-air. The adults in the study made a successful kill in 40% of attempts, while the juveniles were successful 19% of the time.

WhiteRump2 Of the ~5,000 pigeons, about 23% had the white rump-patch I just described above. So of the pigeons killed by the Peregrines over the 7 year study, guess what percentage had the white rump-patch. Probably around 23%, right? Guess again- it was 2%. That’s right, if you were a pigeon in Davis, California over the last decade, having white feathers on your rump made you 10 times likelier to successfully evade a mid-air Peregrine attack.

Actually, that’s not quite right. I should say, having white feathers on your rump made you 10 times likelier not to get killed by a Peregrine, period. Because while the juvenile Peregrines attacked White-Rumpers about as often as they attacked any pigeon- roughly 20% of the time, adult Peregrines only bothered to even try to catch them about half as often- only 10% of the time. The adults clearly learned that White-Rumpers were harder to catch, and so most of the time focused on other, easier-to-catch color patterns.

What was going on? Could White-Rumpers be faster, smarter or more maneuverable than other pigeons? Apparently not; the researchers captured over 700 White-Rumpers and Blue-bars and switched their rump-feathers, whereupon the (former) White-Rumpers lost their advantage and the Blue-bar-transplants suddenly became 10 times harder to catch!

All About Peregrine Attacks

To understand the advantage of the white rump-patch, we have to know a bit about how Peregrines catch pigeons. Peregrines target pigeons from high above. When they lock into a target, they go into a dive, reaching speeds of over 200 mph*. PAttack TrajectoryThe falcon levels off from its dive on the level of the targeted pigeon, at a point 20-100 meters behind it. Pigeons are themselves fast- racing pigeons have been clocked at 94 MPH- but not fast enough. The Peregrine closes from behind and catches the pigeon in its talons. Well, 40% of the time, anyway.

*Fastest animal on the planet.

Target1 The other 60% of the time, the Peregrine misses, and it misses because the pigeon takes evasive action. The most common evasive maneuver is a roll, which the pigeon effects by dropping one wing and quickly rolling 360 degrees over and down to a plane below the Peregrine’s attack trajectory.

Target2 To be able to catch the pigeon, the Peregrine must quickly modify its (very high-speed) trajectory, and to do so it must observe and react to the pigeon’s wing-drop, which marks the beginning of the roll. But for some reason, the white rump-patch appears to make the Peregrine less able to detect the wing-drop and correct course in time. Somehow this bright white spot distracts the falcon’s attention from the wings, and it misses the pigeon.

Target3 Wow. White rump-patches sound awesome! Why don’t all feral pigeons have them? Well, not all feral pigeons are regularly exposed to Peregrines, and for a few decades, hardly any were. In non-Peregrine environments, it’s not obvious that they offer any other benefits, and who knows, they may be a liability when confronted with other predators. In the 1960s Peregrines came close to extinction, and disappeared completely from the Eastern US and Canada. DDT weakened their eggshells, which routinely cracked during incubation. But now they’re making a come-back, and re-colonizing much of their former range. And, like pigeons, they seem to adapt well to cities, nest on high buildings and attracted by the availability of prey (pigeons!) It may well be that the return of the Peregrines is creating a selection pressure for white rump-feathers, and in fact over the course of the Davis study the researchers noticed an increase in the occurrence of this color-pattern.

Extra Detail: The birds that had the roughest time with DDT were those which, like Peregrines or Bald Eagles, are at or near the top of the food chain. DDT (C14H9Cl5) is a chlorinated hydrocarbon, and accumulates in the fatty tissues of creatures who ingest it. The concentration increases as other creatures consume those contaminated tissues, resulting in much higher concentrations in top predators. Seabirds also had a tough time, as they ate large numbers of contaminated fish. Brown Pelicans in particular came close to extinction but are now recovering nicely.

That’s just one pattern and one story. In the many environments- both rural and urban- which feral pigeons inhabit, there may be other color-pattern-benefit stories we haven’t yet figured out.

So it’s time to wrap up Pigeon Week, and I want to do so by returning to the issue I keep mentioning but skirting past- their “feral-ness.”

Wild pigeons were first domesticated, for food, some 5,000 years ago, making them the world’s first domesticated bird. They’ve been bred in captivity ever since, for food, as well as communication and sport (racing), and for as long as people have been keeping pigeons, pigeons have been escaping from them. We know that many ancient cities had flocks of feral pigeons, including Rome, where they roosted atop some of the major buildings and monuments.

Pigeons were introduced to North America in 1606 by French colonists in Nova Scotia, and starting escaping shortly thereafter. Today in pretty much any major city in the world, you can easily find feral pigeons. They’re everywhere, and it’s hard to think of a bird that’s doing better in the human-altered world of today.

IMG_4322 Which is ironic, because wild pigeons may be close to extinction. Not last-guy-dropping-dead extinction, but genotypic extinction. As feral pigeons expand their range and multiply, they’re both cross-breeding with, and simply out-breeding, wild pigeons when coming into contact with them. By the end of this century, there could well be no truly wild pigeons anywhere in the world.

This isn’t as weird or unusual as it may sound. An example we see all the time is ducks. The common duck you see in parks or on ponds is the Mallard, Anas platyrhynchos. Mallards are another exotic, introduced to North America by Europeans, and the wild ducks we see here today are- yes, that’s right- feral. Mallards interbreed with many native ducks when encountered, and it’s believed at least some native North American ducks, such as the American Black Duck, A. rubripes, may already be genotypically extinct, surviving today only in hybrid form. Similar possible gentotypic extinctions are happening or have happened with native ducks in Hawaii, South Africa, and elsewhere. Genotypic extinction isn’t just a bird thing either; as we saw almost 2 years ago, exotic Old World triploid Dandelions present a similar threat to the remaining North American species.

Tangent: There’s a weird parallel with some human populations (though I want to be careful and make clear that the differences between disjunct populations of modern humans are nowhere near the level to be considered separate “species.”) Truganini, the last full-blooded Tasmanian aboriginal, died in 1876, a tidbit referenced in a number of sources as the “extinction” of the native Tasmanians. This “extinction” moniker has ticked off a number of modern-day Tasmanians, who while not full-blooded, claim Tasmanian ancestry. It’s probably more accurate to say that Tasmanian aboriginals are genotypically extinct.

Nested Tangent: While I’m diving into borderline-taboo human ancestry topics, I can’t help but noting another parallel- this one more inspiring. Successful feral species make me think of human populations whose ancestors escaped from bondage. The one we’re probably all most familiar with is the Israelites’ escape from Egypt, but recent (and historically clearer) stories are right in our back yard.

The recent earthquake in Haiti is yet another in a series of tragic mishaps to befall that nation, and nowadays when we think of the place, we regard it mostly with sadness and pity. That’s sad in and of itself, but it’s doubly sad in that it obscures the human triumph of Haiti’s founding: an enslaved people who united, rose up, successfully overthrew their masters, and founded a nation- a story unique in the hemisphere (maybe the world?), something accomplished by no other modern people. And while they didn’t give rise to a nation-state, the stories of the Jamaican Maroons or the Garifuna of Central America are no less inspiring. For me, these are some of the most stirring stories of recent human history and at some level I envy these peoples the pride they must feel of the sacrifices and accomplishments of their ancestors, even if I don’t envy their present circumstances.

But the mallards, while interfertile, are a different species; feral pigeons are the same species as wild pigeons. Why would they outbreed them?

Domesticated animals are bred for traits desirable to their human masters, a process called artificial selection, which has produced the array of domestic pets and livestock we see today. Domestic pigeons have been bred for several traits, one of which is fecundity. Domestic pigeons regularly rear as many as 18-20 squabs per year. I mentioned in part 2 that feral pigeons in temperate latitudes breed year-round. But what I didn’t mention is that wild pigeons don’t; year-round breeding is a legacy of human domestication, and their feral descendants, with their human-induced powers of fertility, are steadily out-breeding their wild cousins.

Tangent: I’m fascinated by feral animals, their origins and lifestyle. Sometime I wonder if, long after we humans disappeared, if evolution were to somehow eventually bring some feral species- pigeons, ducks, dogs, horses to a state of human-like intelligence and self-awareness, and these future pigeonoids or duckanoids or whatever were to investigate and research and come to understand their evolutionary past, including their domesticated origins, how might they regard us? As protectors? Parasites? Angels? Gods?

IMG_4316 That’s Pigeon Week. I hope you enjoyed it, and that the next time you notice a flock of pigeons you don’t just dismiss them as “feathered rats.” They see and sense a world beyond the one you or I see, their family lives are exemplary, and their story inspiring. Pigeons are way cool.

This series feels like kind of a milestone for me in this project. We’ve checked out some several of the most common, taken for granted birds around, including the 3 Big Exotics (Pigeons, House Sparrows and Starlings) as well as our own local signature corvid (Magpie.) In each case their stories have turned out to be way, way more interesting than I ever would have guessed when I decided to check them out. And that’s really been the big epiphany of this whole project for me: that everything, every living creature, not just the rare or unique or exotic, but the most common, “boring”, ordinary, everyday creatures, things like Pigeons and Dandelions and Crabgrass and Box Elder Bugs and Yellowjackets have these amazing stories behind them. It feels good to understand and connect these stories. Sort of like, after all these years, the world is starting to make sense.

Note about sources: It was a pleasure to research a topic with so many excellent sources available. I’m extremely grateful to my friend and fellow nature blogger KB for helping me track several of them down. Much of the info for Parts 1 and 2 came from this site and this site, which also provided much of the plumage info for Part 3. This paper provided the data of the Davis, California plumage study referenced in Part 3. This paper detailed the possible genotypic extinction of wild pigeons. Additional info came from Colin Tudge’s outstanding book The Bird, and from the Cornell ornithology website. (And I’m forgetting probably a dozen other very helpful sites.)

Friday, February 12, 2010

Pigeon Week Part 2: Mating, Meiosis and Milk

The next way cool thing about Pigeons is how they raise their young. The next time you hear someone go on about “feathered rats”, consider this: on average, Pigeons are arguably more doting- and certainly more egalitarian- parents than we are. Pigeons are prolific breeders* and both sexes take the business of child-rearing quite seriously.

*Feral pigeons, especially, for reasons we’ll get into in Part 3.

Climate permitting, feral pigeons breed year-round. Here in North America that means they’ll breed year-round, or close to it, up to about latitude 40 degrees North*. In the UK, it’s clear up to 54 degrees North.

*Which is, by wonderful coincidence, the latitude of Salt Lake City. How cool is that? Pretty freaking cool, that’s how. I tell you, the longer I live here, the more I feel like it is the center of the universe.

IMG_4262 Pigeon courtship involves a fair amount of cooing, bowing, playful running, and- apparently- foreplay, including something called “billing”, in which, in a weird analog of French-kissing, the female inserts her bill inside the male’s open bill, usually with both their eyes closed. Following mating, the male often makes a brief “display flight”, in which he claps his wings behind his back*. Pigeons mate for life.

*I love this. It’s like he’s strutting about, high-fiving himself.

About 10 days following mating, a female pigeon lays 2 eggs, roughly 40 hours apart. There are 2 really interesting things about these eggs. The first is that the eggs are almost always 1 male and 1 female, which seems neat but odd. In pigeons, like all birds, sex is determined chromosomally, in a manner similar to- and yet completely opposite from- that of mammals.

This Part You Already Know But I Included It Because On The Off-Chance You Don’t Know It You’ll Get Totally Lost

In mammals, like us, sex is determined by an XY chromosomal system. We have 46 chromosomes arranged in 23 pairs. Each pair represents 2 of the same type of chromosome, one of which received from our mother, the other from our father. The exception is our sex chromosomes. Females have 2 of the same type, called “X’, but males have 1 “X” and one “Y”. Only men carry a “Y” chromosome. When a human female produces an egg, it contains just 23 chromosomes*, one of which is always an “X”. When a human male produces a sperm cell, it contains just 23 chromosomes, one of which is either an “X” or a “Y”. So the chances of a human couple conceiving a boy or a girls are, generally speaking**, 50%.

*The obvious exception is the occurrence of trisomy caused by the production of a sex cell (by either parent) that contains 2- and not just 1- chromosome at a given location, resulting in a fertilized zygote containing 3- and not 2- chromosomes at that location. Trisomy can occur on any chromosome, but is only survivable (to birth) at a few locations, including the X/Y chromosomes, and chromosomes #21 (Down’s Syndrome), #13 or #18 (the latter 2 always resulting in severe birth defects.)

**It’s actually a bit more complicated than this. Slightly more human boys than girls are born. But that’s a topic way outside the scope of this post.

This Part You Already Know If You Are A Longtime Reader Of This Blog (Or Just Knowledgeable About Birds)

In birds, the exact opposite is going on. Pigeons have 18 chromosomes arranged in 9 pairs, 1 of which is the sex chromosomes. But it’s males who have the same chromosome- called “Z”- while females bear 1 “Z” and 1”W”. Only female pigeons carry a “W” chromosome. When a female pigeon produces an (unfertilized) egg*, it contains just 9 chromosomes, one of which is either a “W” or a “Z”. When a male pigeon produces a sperm cell, it contains just 9 chromosomes, one of which is always a “Z”. So the chances of a pigeon couple conceiving a male or female squab is, generally speaking, 50%.

*As opposed to a fertilized, make-an-omelette kind of egg. So I guess “egg” is loaded term here, and I probably should say “ovum.”

PPSQ1 If you have a 50/50 chance for a boy or a girl, and you have 2 children, then out of the 4 possible combinations- boy-boy, girl-girl, boy-girl, and girl-boy- 50%, or 2, of your two-child pairs will include 1 boy and 1 girl, and the other 2 will be either both boys or both girls*.

*And of course this is the case with human fraternal twins, such as Twin A & Twin B. The reason most twins overall are one sex or the other is because all identical twins are always the same sex. BTW, the single dopiest question you can ask a parent of boy-girl twins is, “Are they identical?” Seriously, you might just as well tattoo “I HAVE NO CLUE” across your forehead.

PPSQ2 Only with pigeons, that’s not what happens. The vast majority- far more than 50%- of pigeon squab nest-mates are male-female. How can this be? The mechanism is unknown.

It gets even weirder. 70% of the time, the first egg laid is male, and the second, ~40 hours later, is female. How can this be? Again, the mechanism is unknown. The male, laid earlier, generally hatches before the female, begins eating, and gains weight rapidly. If food is sparse, and only 1 squab makes it, it’s usually the slightly bigger, first-born male who survives, and the female who dies. The benefit of laying the male egg first seems to be a greater survival likelihood for the male, though the advantage of this to the parent is unclear.

Conjectural Tangent*: Whatever’s happening, it’s happening in the female. Remember, the “W” chromosome can only come from her, so it’s her ova that are determining the sex. Presumably there’s some benefit to pigeons, some slightly better statistical success-payoff in the long run, to bearing young in pairs of opposite sex. And presumably, if only one of your 2 squabs is going to make it, there’s some slightly better statistical success-payoff in the long run if that survivor is male ~2/3 of the time.

*Warning: All of my conjectural tangents are just that- totally conjectural, and almost certainly wrong. But they’re fun to think about.

I say “presumably” because of course I have no idea. But there are millions and millions of pigeons, with an average generation-time of just a couple of years. And across thousands/millions of years, and billions of pigeons, these weird statistics have worked out and hold steady worldwide. There has to be a long-term statistical driver behind it.

So somehow, female pigeons have evolved to either a) release 2 ova roughly concurrently, but slightly staggered, or b) release 2 ova concurrently, but, following fertilization, stagger development of the embryos by roughly 40 hours. And more remarkably, she’s evolved to produce these ova, in most cases, alternating between W and Z ova, which in turn implies that whatever mechanism is at work here is at the meiosis level. That’s incredible! How is it controlled? What is going on?

Meiosis- or the division of diploid cells into haploid gametes- is the process by which all sex cells are created, and occurs in 4 distinct phases, encompassing 2 stages of cell division. I won’t go through all the details, but in human females, the first phase- called Prophase 1- happens before birth. In Prophase 1 the chromosomes in the initial germ cell split, which, in a female bird, means that one half ends up with a “W”, and the other with a “Z.” The proto-eggs then remain “on ice” until puberty, when they complete the meiosis process. But the initial splitting of the germ cell’s chromosomes happens in Prophase 1.

Does the timing work this way in birds? I don’t know*. But if it does, it would mean that the sex determination of gender- which ultimately occurs in Prophase 1, specifically in the female- would happen before birth. If this is the case, it means that somehow the female pigeon is positioning or packaging eggs, by gender, for eventual sequenced release, before birth.

*Specifically, does Prophase 1 occur before birth? I spent- no kidding- an hour online trying to find out before I gave up.

NOTE 9/22/10: Anonymous commenter answered this footnote-question. In birds Prophase 1 occurs 24-48 hours before ovulation (very different from the timing in mammals). See comments for details, source..

This sounds crazy, but the other possibility sounds even crazier: the female pigeon, as an adult, actively and real-time recognizes and sorts eggs by gender internally. How could this be? What “signature” would an egg bear based on whether it contained a W or a Z chromosome?

Whatever is going on inside of female pigeons, it is some seriously complicated shit.

The couple shares incubation duties, the male incubating by day, the female by night. After about 18 days the 2 eggs hatch, usually about 24 hours apart. After the squabs hatch, the parents feed them, which is pretty normal for all sorts of birds. But what they feed them is not; they feed them milk.

It isn’t actually “milk”, in the strict, mammalian sense of a white emulsion of fatty globules in a water-based fluid. But it is a remarkable analog, and like so many avian-analogs we’ve looked at- color vision, foveal vision, thermoregulation, gender-determination, intelligence/self-awareness- it’s a fundamentally different way of solving the same problem.

Crop Graphic Pigeon milk is produced by fluid-filled cells lining the crop, which is a specialized organ present in many birds, located at the bottom of the esophagus, and generally used for food storage. Crops are thought to have come about as a mechanism for a bird to quickly gather and accumulate food from a location more rapidly than it might consume it, thereby minimizing on-location exposure to potential predators. Pigeons and game birds tend to have larger crops. The evolution of development of “milk”-production in the crop is an apparent example of an exaptation, or the leveraging by natural selection of a component(s) originally evolved for a different function.

Pigeon milk, like mammalian milk, is a highly nutritious, easy-to-consume, digest and metabolize food source rich in fats and proteins. Only more so: the protein, fat and overall dry matter content of pigeon milk is higher than human or cow milk. “Milk” is also a misnomer in that the substance secreted is more like a yellowy cottage cheese in appearance and texture, consisting of 35% dry matter, compared with 8% dry matter for human, and 4% for cow milk.

For the first several days, the squabs are fed the milk by their parents, who regurgitate it up from their crops, and into their mouths. After a few days, the parents add regurgitated seeds- mixed in with the milk- to the squabs’ diet, and gradually wean them off the milk at around a week or so.

Tangent: To a human, regurgitating food into someone else’s mouth sounds like, well, the grossest thing imaginable. But it’s remarkable how common it is in the animal world. Birds do it all the time, as do all kinds insects, and wolves regurgitate partially-digested meat to their pups. Lots of critters do it, and it seems to work just fine. And besides, I suspect some of the things we do would seem pretty disgusting to other creatures. I sometimes think that to an egg-laying creature like a bird, a live birth must be about the grossest thing imaginable.

The evolution of “milk” in pigeons is cleverer than it seems. Pigeons are mainly vegetarians; they don’t generally eat bugs. One of the challenges for non insect-eating birds is getting enough protein to their chicks that they attain critical mass prior to fledging*. Some species alter their diets to include bugs when in need of additional protein, but milk-production represents another solution to the problem.

*And it was this aspect of House Finch diet that turned out to be the undoing of the Brown-Headed Cowbirds who parasitized their nests, as we saw in last year’s Bird Feeder Week. (Man, was that an great week or what?)

flamingo2 Side Note: Still another cool thing about milk-production in birds is that it has evolved multiple times independently. Flamingoes (pic right, not mine) feed “milk” to their young, which is produced, not in a crop, but rather in glands lining the upper digestive tract. In a creepy vampire-like twist, the milk contains large numbers of both red and white blood cells. Emperor Penguins (pic below, left, not mine) also feed their chicks “milk”, in this case produced directly in the esophagus.

penguin1 Interestingly, though all 3- pigeons, flamingoes, and penguins- produce milk, the evolutionary drivers for doing so appear to have been different. In pigeons it was driven by the need to ingest maximum protein prior to fledging. In flamingoes, they’re only able to ingest liquid food while their specialized feeding apparatus develops. In Emperor Penguins, it serves as a critical supplement in a food-barren environment. (Penguins eat fish, but incubate/hatch eggs fairly far inland.)

If you didn’t notice already, I’ve been glossing over something in my description of pigeon milk. I’ve consistently said “parent” in place of “mother”, and the reason for this is that both sexes of pigeon produce milk, starting to do so a few days before eggs hatch. With the exception of a couple of species of bat, no male mammal is known to routinely produce milk.

Pigeon Nursing I’ve already mentioned the admirable parenting habits of pigeon-fathers, and such behavior isn’t unusual in the world of birds. Although certainly many bird species are “bad dads”, the males of many, many species are exceptional caregivers, and in many species even assume the lion’s share of incubation and chick-rearing duties. In mammals, with a few notable exceptions, such as humans and wolves, the vast, vast majority of species- including bears, cats, deer, rats, and former presidential candidates from North Carolina- are completely uninvolved- if not outright absentee- fathers. 90% of bird species are primarily monogamous*; only 10% of mammal species are.

*Though virtually all will cheat, given circumstance and opportunity.

One reason why this might be so is eggs. A female mammal carries her young until birth, and there’s not all that much many male mammals can or need do to help things along. By the time the offspring is delivered, he’s long gone. But since so much of a bird’s prenatal development takes place outside the mother, it opens up all kinds of incubation and egg-protection scenarios, many, many of which involve ongoing paternal participation, in turn keeping the male around till hatching. Some number- a big number- of these high-paternal-involvement scenarios led to more chicks surviving to hatch, fledge, mature and mate, which in turn led to… well, you get it already.

The Phenomenal Unfairness of Being Born Female

Tangent: Thinking about birds and mammals and gender always leads me back to thinking about humans and gender, which leads in turn to what for me has always been one of the big, unfathomable mysteries of life: the unfairness of being female.

Any rational way you slice it for a human being, being born female seems like a bad deal. They’re physically weaker, and their entire bodies are, well, structurally compromised for child-bearing. To pass a human head during delivery, our females’ hips have become so wide that women basically walk wrong. Routine childbirth for humans is a far more traumatic, painful, and life-threatening event than it is for pretty much any other large mammal. Every month women are plagued with inconvenience and discomfort, and although all humans fall victim to cancer, breast cancer strikes down under-40 women in their prime far, far more often than prostate cancer afflicts similarly-aged men.

Women routinely live with threat (or reality) of sexual or spousal violence, and the common, unwanted attentions of people bigger and stronger than them. In love, the penalties of misjudgment, indiscretion, or plain bad luck (unplanned pregnancy) are always greater for women, in terms of health, time, missed opportunities and cultural stigma. In the majority of human societies throughout history, and arguably today, women have enjoyed far fewer legal and property rights. Even in modern America, women earn less, and are remarkably under-represented politically.

Obscenely-priced cosmetics and hair products, burkhas/ veils/ headscarves, pantyhose that endure only a handful of wearings, shoes that are both exorbitant and borderline un-wearable. How do they stand it?

Nested Tangent: There’s another mystery to me embedded in this one, and that is how theists- people of faith- regard gender. Theologians seem to spend endless cycles considering or debating specifics of the afterlife, the path to salvation, or the duality of Christ, and yet, with a few exceptions (immaculate conception, virgin birth, original sin), don’t seem to think much about the greatest of God’s mysteries: How’d he pick who gets/has to be male/female? Specifically, do souls have gender? Or are souls neuter, above/beyond gender and base sexuality, and we’re simply assigned a gender in this life. If gender is assigned, what did women do to deserve their female-ness*? And if they’re not assigned, how does God decide which souls to make female?

*Yes, I’ve read Genesis, and I say, “Give me a break.” Assigning punishment to the great (x-times) great granddaughter of a “criminal” is even more morally repugnant than the psychotic-feudal family labor camps of North Korea.

If souls don’t have gender, and you believe in an afterlife, are you and your spouse really going to want to hang together for eternity? Doesn’t anybody think about this stuff*?

*Yes, I know some people do. Mormons are a good example. In Mormon theology, soul is definitely linked to gender, and that’s important, because married couples remain together in the afterlife. For me though, that opens up a whole other can of worms. I love AW dearly, but I wonder if after 500, 10,000, or a million years or so, what would we talk about? Seriously, at some point, after a few millennia or so, you must wake up every day and be like, “What- you again?” Anyway, I don’t think there is an afterlife, but if there is I’m thinking maybe I’d like to play the field a bit.

But that- none of that- is the unfathomable part to me. No, the unfathomable part is that the vast majority of women with whom I’ve had this conversation don’t agree* with me. They’re glad they were born female! How can this be? Don’t they see what an awful, terrible hand life has dealt them? It seems sometimes that no matter how long you live around women, so much about them is forever a mystery.

*Of course, at some level I generally find it unfathomable that anybody ever disagrees with me about anything, but then I guess that’s part of the unfathomable mystery of being male.

After about 4 days, the parents begin to augment the squabs’ diet with regurgitated seeds mixed in with the milk. By day 8-10 they’re almost fully weaned, being fed just seeds. At around day 30-35 they leave the nest.

But usually around day 20 the female lays the next pair of eggs, initiating a somewhat crowded period in the nest called clutch overlap. Clutch overlap is a busy time, with both eggs to incubate and mouths to feed. Guess who picks up the slack? That’s right- Dad. During overlap the male assumes a majority of feeding duties for the squabs.

Clutch Overlap Clutch overlap, and the rapid, year-round reproductive cycle of pigeons leads to perhaps the most interesting questions about them: Where are they from, and how come there are so darn many of them?

Next Up*: Coloration, Defense, and the Remarkable Natural History of Feral Pigeons.

*Will bleed into next week. These theme “weeks” are tough to pull off on schedule. But aren’t pigeons cool? Jason? Hello? I am talking to you.

Thursday, February 11, 2010


Sorry, what can I say. Up early for a frozen mtb ride, crazy day at work, worked some more after dinner, then tucked into Part 2. Almost wrapped it up, but bonked completely around 10PM, before I could get to graphics. Anyway, here’s a teaser: if you’re male, I’m willing to bet my next paycheck that a typical male pigeon is a better dad than you are. No kidding*.

*Actually I am kidding. Not about the better dad part, but about the paycheck part. I don’t care if you’re like the Jesus of Dads, I’m not giving you my paycheck. I’m not even giving you like 5 bucks. (But I’d probably give you a WatcherSticker.)

Little more filler- here’s a quick clip from yesterday’s pre-work ride in City Creek. Nice higher up, but the icy switchbacks down lower are pretty scary.

And for anyone who actually was hoping to learn something here today, go check out Berry-Go-Round at the Phytophactor. I always learn something at BGR, and Phytophactor, unlike me, is a plant-freak who actually knows what he’s talking about.

Tuesday, February 9, 2010

Pigeon Week Intermission: The Throwdown

Pigeon Week will continue tomorrow, but today just some quick catch-up/filler.

I really believe that the world is divided into two kinds of people: People who already know that pecan pie is the best kind of pie ever invented, and People Who Just Don’t Get It*.

*Sadly, (Otherwise) Awesome Wife is in this category. Her favorite pie is cherry pie. Which would be OK, except that she’s sort of like a Cherry Pie Communist Party Boss. Before every family holiday, she’ll poll various family members as to what kind of pie they’d like to have. (We choose 2.) She’ll take everyone’s “vote”, tabulate and then happily announce the results, which, remarkably, always include cherry, even though I’m reasonably certain that no one besides her has ever cast a vote for it.

Anyway, Friday night was a pecan-pie-lover’s dream come true. One of the nice, unexpected side-benefits of this project is some of the great friends I’ve made through blogging. Now 2 of these friends- Rachel and Jube- are formidable cooks. And it came to pass a month or so back that some smack-talk was exchanged regarding who made the best Pecan Pie. Things escalated from there, and so it was that Friday night several of is gathered at the Watcher Family Headquarters for the first ever Salt Lake Valley Pecan Pie Throwdown, a truly epic competitive event.

The Pies Tangent: Pecans, BTW, are way cool. First off, even though they look like Walnuts, they taste sweeter, less bitter, and way, way yummier.* The two are fairly closely-related, both belonging to the Walnut Family, Juglandaceae**. Botanists go back and forth on whether Pecans and Walnuts are true nuts or drupe fruits (the part you eat is endocarp), similar to apricots, plums and almonds***

*Totally my opinion, no science whatsoever to back it up. Hey, it’s a Filler-Post, lighten up!

**Not a family we’ve looked at before. It’s part of the order Fagales, though, which includes Oaks, Birches and Beeches.

***Though not closely-related to any of them (those guys all belong to the genus Prunus, within the Rose Family.) Drupe-style fruit architecture has evolved independently multiple times, even just within the Rose family.

But the coolest thing about Pecans is that they’re an “American Original”, native to North America, and one of the “newest” commercial crops, having been domesticated only since the 1880’s.

Bonus Tangent: So are Walnuts native or exotic? Sort of both. There are Walnut species native to both the Old and New World. The walnuts we eat are generally from the Persian (or English)Walnut, Juglans regia, which has been grown commercially in California since the early 1800’s. But interestingly, in the 1890s, growers switched to grafting J. regia onto rootstock of the native Hind’s Black Walnut, J. hindsii, for that species’ superior disease resistance. In the 1950’s, growers switched rootstocks again, to the “Paradox Walnut”, a hybrid of J. regia and J. hindsii, and that’s what grows most of the walnuts we eat today.

The contest was delightful but challenging, and judges UTRider, Blackdog and yours truly* summoned all of their powers of taste amd discernment in awarding the prize. But when the votes were cast, Jube was declared Pie Queen.

*SkiBikeJunkie was also present but was DQ’d as a judge on account of allegedly having slept with one of the contestants. He briefly denied the charge in hopes of participating, but their 3 children ratted him out.

Pie Queen It should be noted that Rachel’s pie was also fantastic, and in fact won first place in the Elite Youth Judging Panel.*

*BirdWhisperer, Twin B, UTboy and UTgirl. JunkieGirl was DQ’d on account of allegedly having been delivered and raised by one of the contestants.

Monday, February 8, 2010

Pigeon Week Part 1: Navigation & Magnetic Fields

I have a list of things I want to blog about in this project before I’m done. Some of them I’m not aware of till I see them, but others I’ve been fully aware of since day 1. Pigeons are in the fully-aware category. I originally planned to do a “Pigeon Post.” But when I learned a little bit about Pigeons and how amazing they really are, I just had to declare this Pigeon Week.

Pigeon1 Now I know you’re probably thinking, “What? How’s he going to get a whole week out of Pigeons? This sounds lame. I’m so checking out for a week…” Yes, yes, I know- “feathered rats” and all that. But I am telling you, Pigeons are Phenomenally Way Cool, and if you stick with me, by the end of this week you will never look at them the same again. So here we go:

One of the odd things I’ve learned about winter is that it’s actually a really good time to check out birds. On the face of it this makes no sense at all; most birds are gone in the winter. But what I’ve found is that because there are far fewer species of birds about- and far fewer bird-cries in the air- that this somehow makes it easier to really notice the birds that do stick around. Magpies are a great example, as are Scrub Jays and Dark-Eyed Juncos. Pigeons are another. Unlike many of the birds I’ve blogged about, Pigeons aren’t endemic, or even native, to the Western US; they’re everywhere, on all continents except Antarctica, from sea level to 14,000 feet.

Cere1 When I say “Pigeon” this week, I’ll be talking specifically about the common Rock Dove or Rock Pigeon, Columba livia*. More broadly speaking, “pigeons” and doves- which are really the same thing- are any one of 300+ species within the family Columbidae. Columbids are stout-bodied** birds with short necks, short beaks and a small fleshy protuberance atop the beak called a cere. An example of a native columbid here in Utah is the Mourning Dove, Zenaida macroura***

*An astute reader might ask if I’m talking about wild, domestic or feral C. livia. We’ll get to that in Part 3, but for now assume feral.

**Wikipedia’s term. I was going to say “plump.”

**Which deserves- and hopefully one day will get- a post of its own.

There are so many cool things about Pigeons that it’s hard to know where to begin, so let’s start with something everyone knows: they’re fantastic navigators. We’ve all heard of homing pigeons, and their remarkable ability to return to the home roost from hundreds of miles away, traveling across unfamiliar terrain. Humans have been using pigeons to carry messages for at least 3,000 years* and in doing so have been credited with a critical role in many wars, including both world wars.

*Pigeons have been domesticated for at least 5,000 years, as we’ll talk about in Part 3.

We’ve heard so much about homing pigeons that it’s easy to forget that “homing” isn’t something that suddenly came about when we humans decided to start sending messages around; Pigeons have been regularly using their formidable navigational capabilities for thousands- maybe millions(?)- of years, and in fact use them daily in the wild.

pflight2 Here’s something cool: we’ve all seen- or maybe see every day- pigeons around cities. Pigeons adapt readily to urban environments, nesting under overpasses or in the eaves of high buildings, as these spots are similar in many ways to the rock ledges and overhangs in which their (truly) wild ancestors nested. For a pigeon, a modern city or town is a wonderfully convenient assemblage of nook-and-cranny filled cliffs, as good as- or better than- any grouping of natural nesting cliffs. But what you maybe didn’t know is that many urban pigeons are commuters- specifically reverse commuters- who each day fly out to suburban or rural areas to forage and then nightly return to their downtown nests. Pigeons navigate for a living.

Tangent: For years I’ve noticed pigeons flying by my office window. But I never really had a handle on where they roosted. Then last week I changed one of my standard running routes, and stumbled upon a big pigeon roost, in the strip mall at 1300 East and 8600 South. And I noticed as well that pigeons really dominate the stretch of 1300 East between 7800 South and 8600 South.

IMG_4283 And this in turn has lead to a blazingly-obvious “epiphany” which I somehow never noticed until last week: Birds have neighborhoods throughout developed areas, and in fact certain flocks of certain species dominate specific urban/suburban blocks. I’ve blogged previously about how the local Magpie flock aggressively controls Sunnyside Ave between my house and the zoo. There’s another flock dominating the cottonwoods and willows on Union Creek Road just between I-215 and Ft. Union Blvd, where I exit the freeway for work every day. My standard 5-mile lunch-run loop includes a stretch along 1000 East between 7800 South and 8600 South which is solid Starling territory, although there’s a dense, tightly-controlled, 2-to-3-yard* “cell” of House Sparrows around 8000 South.

*”Yard” in this case as in the yard of a house, not the unit of measurement.

Bird Territories Office These little “city-states” must change with season and migration throughout the year, and what I’ve realized this past week is that throughout the valley, superimposed upon and around us, is this whole, fantastically complex, dynamic, multi-species, socio-political landscape/map to which 99% of us are completely blind. How did I miss that for so long?

The interesting question is how pigeons navigate, and this question has 2 parts. The first is: how do pigeons navigate mentally? Meaning are they just following a path of memorized cues or landmarks? Or do they construct a mental map of their surroundings and intended destination?

Until the latter half of the 20th century, it was unclear how pigeons homed. One hypothesis was that pigeons simply homed by following the outbound path they had taken away from the roost. Many animals, such as ants, use this type of Hansel & Gretel approach, following landmarks recognized and/or marked (by scent in the case of ants) on the outward journey. But observation quickly ruled out Hansel & Greteling for pigeons on 2 counts. First, pigeons transported to remote locations blindfolded home just fine. And second, pigeons returning home from the same location multiple times don’t follow the same exact path. (Remember this- we’ll come back to it.)

pflight3 So pigeons seem to use a mental map. But what sort of map? The simplest “map” in animal navigation is a cue gradient map, in which the animal extrapolates from remembered landmarks or cues to determine location and course. These cues may be visual, olfactory (smell) or magnetic. But a simple cue gradient map is limited as to how far it can be extrapolated, and it doesn’t really require a compass. Pigeons navigate hundreds of miles across unfamiliar terrain, and have not just 1, but 2 internal compasses. Most researchers today agree that pigeons construct true spatial navigation maps.

Tangent: In thinking about animal navigation, it occurred to me that we humans use all three methods: simple track-following, cue-gradient maps, and full spatial-mapping. Here are 3 examples.

Until 2 years ago, my parents lived in the house where I grew up. When I visited once or twice a year, I’d return to their house from the airport (by either taxi or rental car) by simply following the same exact set of landmarks: Callahan Tunnel, 93 North, Mystic Valley Parkway, Right at the Armory, Left at the rotary, past the cemetery, the town-line sign, left at Simms’ Corner, up the hill. But 2 years ago my parents moved across town to a townhome, and I had to think just a little bit more about where I was going. The townhome was still in my hometown, so I didn’t have to consult a map or ask my parents for directions, but I had to reference additional memorized “cues” in getting to their home- the train station, the plant nursery, the street where I first rode a friend’s motorcycle, the intersection where a college student broadsided our Toyota station wagon on the way to church. I don’t exactly go past all of these places, but they’re reference points I think about to get me to the condo. So nowadays I use a cue gradient map of sorts to get to my parents’ place.

Hometown Cue Gradient Map Last night I flew into San Jose and took a cab up to a hotel in Santa Clara. Before I left home I checked out a map online to get a feel for the route. Though it was dark when I landed, I paid attention to the turns and direction the driver took, tracking the route along unfamiliar streets using the spatial-navigational map I’d constructed prior to take-off.

Nested Tangent: I’ve traveled hundreds (thousands?) of times for work and pleasure in 47 US states, 26 countries and a couple hundred strange cities/towns, and I almost never use a GPS navigation system. I love route-finding; it’s one of the most enjoyable parts of being human. Really, if you can’t find your way around, I think at some point you have to stop and ask yourself: are you really fully human, or a just a good-looking chimpanzee who somehow learned to speak? (Then again I’m one of those weird guys who hates automatic transmissions, so don’t pay me any mind* if you like GPS’s and I’ve offended you.)

*This is my polite way of saying, “Don’t bother leaving an irate comment.” Or do- whatever makes you feel good. I really just want you to be happy. If you’re a GPS-addict and I’ve offended you, then please go ahead and leave a snarky comment. You’ll be filled with a righteous, well-I-told-him-what, sense of well being, and you won’t hurt my feelings at all. I’m actually happy whenever I get comments, even when it’s that Indian flower-delivery place that spams my comments sometimes.

The second part of the question is how pigeons construct and follow these navigational maps. Are they visual, olfactory, magnetic? The evidence seems pretty conclusive that pigeon maps are both visual & magnetic.

The vision of birds is something I’ve covered in several previous posts, so I won’t spend a lot of time on it here, but the short version is that it blows ours away. Bird vision excels not only in distance and clarity but also in color.Human Eye Cones We humans are trichomatic*, meaning that our retinas have 3 different kinds of cones, or color-wavelength receptors, which are optimized for (relatively speaking) long, medium and shorter frequencies of visible light. Most other mammals are dichromatic or monochromatic, meaning that we see a more colorful- and possibly more detailed**- picture of the world than they do.

*Most of us, anyway. Plenty of people- mostly men- are dichromats or even monochromats, and some number of women may actually be tetrachromatic, as we discussed in this post.

**When I say “possibly”, I mean it. There’s a case to be made that in at least some instances, decreased sensitivity to color enables one to notice detail less clear to those with full color vision. The classic example is colorblind aviators in WWII bomber crews who were supposedly better able to spot camouflaged targets.

Bird Eye Cones Droplets But pigeons have 5 different cone types, making them pentachromatic, and what’s more, they have specialized color-tinted oil droplets covering some of their retinal cones which shift wavelengths of light before they reach those cones, thereby optimizing those cones for yet additional wavelengths. In the case of pigeons, it appears that their eyes are therefore effectively at least octochromatic, meaning that they see a world with almost 3 times as many colors as you or I.

At the risk of belaboring the obvious, pigeons- and all flying birds- have yet another visual advantage over us: they’re way high up, and so able to visually map on a scale rarely available to us ground-dwellers.

But really, all of that is review; what I want to focus on in this post is magnetic navigation. For nearly 2 centuries naturalists have suspected the Earth’s magnetic field to be implicated in the navigation of many birds, and in fact it appears that not just birds, but also salmon, turtles and even honeybees* utilize magnetic field clues in route-finding.

*The navigation of honeybees is worth a post in itself, and is way complicated. Though I haven’t really researched it, I stumbled across enough references in researching this post that I suspect it involves elements of all 3 mental navigation models- path-tracking, cue-gradients, and spatial-mapping. Like pigeons, it appears to involve at least 2 compasses- visual/solar and magnetic, and even more interestingly, as honeybee vision (they have apposition compound eyes, which I explained in this post) extends into UV wavelengths, the visual/solar compass is still effective on overcast days.

But before we talk about how pigeons “see” a magnetic field, what exactly is the Earth’s magnetic field?

All About The Earth’s Magnetic Field

Way back when the Earth was molten blob, the heavier elements of the blob- including iron*, nickel and cobalt- sank to the core. These elements are ferromagnetic**, meaning that they can be magnetized- and remain so- by a magnetic field. The core of the Earth is still molten, and these molten ferromagnetic elements are moved around through the core- specifically the outer core- by convection currents, which generates a magnetic field.

*Iron BTW is pretty common in the universe because it’s the final, un-fuse-able end product of really, really big stars, as we saw when we covered Orion and supernovas. Like all heavy elements, Iron is the product of exploded stars. Think about that- all the Iron in your life- you car, tools, maybe your bike- was once stuff in a monster-sized star that blew up.

**An atom of a ferromagnetic element possesses electrons in its outer electron shell, yet the next inner shell is not filled, which means that its electron spin moment is not cancelled.

This convection-generated field extends far out into space, deflecting (to our benefit) most of the cosmic rays headed toward Earth. The field has a direction, with an approximate “North” and “South” pole, sort of (but not really) like a bar magnet.

EarthMagField Not all planets BTW have magnetic fields. Venus has a mainly iron core, like Earth, but no magnetic field. It’s thought that Venus’ extremely slow rotation (roughly as long as its year) is too slow to churn things up and get the necessary convection currents going in the outer core. That’s the thinking anyway. In truth much about the Earth’s magnetic field is a mystery, including its alignment and direction. Most people know that the Earth’s magnetic and geographic poles don’t line up exactly right. Right now the Magnetic North pole is somewhere in Greenland up around 79 degrees North. That’s why you need to know the variance between geographic and magnetic North poles (declination) at your location to use a compass accurately. But what’s weird about the magnetic poles is that they’re moving- fast. Since 1831 (when the North Magnetic Pole was located) it’s moved an average of 6 kilometers per year, meandering about (apparently) aimlessly some 1,000 km. Even weirder, it’s speeding up; in recent years it’s been moving more like 24 km/year.

Weirder still, every once in a while the Earth’s magnetic field flips, or reverses. It’s not clear why this happens- everything from Chaos Theory to asteroid impacts has been suggested- but the field has reversed more than 71 times in the last 171 million years. And bizarrely, the reversals don’t happen at regular intervals. Between 120 million and 83 million years ago, the field never reversed once. But around 42 million years ago, the field reversed 17 times over just 3 million years. Why is the pole moving faster now? Is it getting ready to flip again? We don’t know.

Speaking of “poles”, the term is a bit of a misnomer. There really is no magnetic pole “point” you can go stand or plant a flag on; it’s really just the sum or average of the many, many magnetic dipoles aligned by the core-convection processes. A similar misconception is that a compass points to that magnetic pole, as if there were a big underground magnet up in Greenland yanking on the needle. But that’s not really what’s happening; rather your compass-needle is aligning with the magnetic lines of force at your location.

The magnetic field varies in intensity and inclination- or “dip”- across the globe. The field is 3 times as strong in Antarctica for example as it is in Brazil. And while the magnetic lines of force are oriented almost perpendicularly to the Earth’s surface in Antarctica (~90 degree dip), they’re almost parallel in Brazil.

On a local level, the field varies quite a bit. Natural geologic features including mountain ranges and ore deposits have distinct magnetic signatures, lending to regional magnetic topographies. Many of the loudest/brightest magnetic features are man-made, including bridges, buildings, railways and transmission lines. And at a local level, magnetic field details can fluctuate a bit from day to day. (Remember this too- we’re coming back to it as well.)

Side Note: In fact an ice axe or even a large belt buckle can throw off a handheld magnetic compass by as much as 3 or 4 degrees.

Wow, the Earth’s Magnetic Field is way freaky. What was I talking about again? Oh right- pigeons.

So how do we know pigeons navigate magnetically? Because we can mess them up. When pigeons have bar magnets strapped to their heads, their navigation is totally messed up, but only- get this- on overcast days. That’s right, pigeons can manage just fine with their solar compass even if their magnetic compass is jacked, but when they lose sight of the sun, they appear to rely solely on their magnetic compass.

Interestingly the converse is also true. A pigeon’s solar compass is calibrated by its internal biological clock; in other words it knows where the sun is supposed to be at a given time of day. Clock-shifted pigeons, whose day/night cycle has been shifted by isolation and/or relocation (think jetlag), also experience jacked-up navigational ability, but only on sunny days. On overcast days, the clock-shifted pigeons do just fine, because they’re navigating magnetically.

Extra Detail: BTW, the strapping-a-magnet-to-your-head experiment has been tried in all sorts of interesting variants. One version involved strapping a coil* around the bird’s head that effectively reversed the magnetic field, and sure enough, when released on an overcast day they flew 180 degrees away from home. Other versions have entailed blasting pigeon-heads with magnetic blasting prior to release, which seems also to mess them up, though less dramatically. Similar experiments have been conducted with humans- applying magnets or magnetic fields to their heads, transporting them to unfamiliar locations, and testing their navigation/homing skills, but the results have been mixed.

*Specifically a Hemholtz coil.

The magnetic sense of a pigeon seems to be much more than a simple compass. On a large scale magnetic dip angle provides approximate latitude and the mental navigational map of a pigeon appears to incorporate local, small-scale magnetic features and anomalies. Remember how I mentioned earlier that pigeons don’t always follow the same route home? And then how I mentioned that local magnetic fields fluctuate a bit from day to day? It’s suspected that those fluctuations may account for the route variation. (Wow.)

PigeonMagNav But how do pigeons sense magnetic fields? For a long time the prime suspects were specialized receptors on either the retina or somewhere along the neural networks (usually the trigeminal nerve) in the face/head. But research in the last decade appears to implicate the beak. The top of a pigeon’s beak contains numerous very small (1-3 micrometers across) nodules of biogenic*magnetite, the iron oxide (specifically Fe3O4) of which lodestones are comprised, and the most magnetic naturally-occurring material.

*Just means of biological origin. So not like the 6-million-dollar man’s eye, or my father-in-law’s knees.

Magnetite Beak The magnetite-beak connection wasn’t an obvious one. For many years one of the leading alternative explanations to magnetic navigation in pigeons was olfactory navigation. When pigeon beaks were anesthetized, their navigational abilities were impaired, which lent support to the olfactory-navigation hypothesis. But anesthetizing the beak was also anesthetizing the nerves leading to the magnetite nodules, impairing the magnetic sense of the poor* birds.

*And I mean it. When you spend a few days reading about all the annoying and nasty things scientists have done to these poor birds, you really start to feel for them. It’s no wonder they crap while flying over us.

So in the last decade, our understanding of how pigeons appear to utilize magnetic fields appears to be becoming clearer. But none of this tells me what I really want to know: How does a pigeon see magnetic fields and features? What does it look, or feel, like? How does the bird experience a magnetic mental map??

Does a pigeon feel magnetism, as we might feel a breeze on the face, or texture when we run our fingers across a tablecloth? Or is it a slight tug or pull or pressure transmitted to the beak in a more indirect way, like how the “texture” of a rocky trail is transmitted to my hands through the wheel, fork and handlebars of a mountain bike? Or does it smell magnetism, meaning does it come across like a scent of something familiar or welcoming or acrid or spicy?

Or, does it really see magnetism? And while it’s impossible to know, neural networks provide a tantalizing hint. The magnetite receptors in the beak are connected to the underside of the pigeon’s brain by nerves branching off the trigeminal nerve, the main nerve hooking up most everything in the head/face, and one of the dozen main nerve-paths connected directly to the brainstem (as opposed to the spinal cord) in most* land/air-dwelling vertebrates, including us. The trigeminal nerves breaks into many, many pathways in its various connections, but these pathways are grouped into several main branches. The magnetite receptor nerves link into the ophthalmic branch of the trigeminal nerve, the same branch shared by- that’s right- the eyes.

*Specifically there are a dozen in amniotes, which are tetrapod vertebrates with- or descended from creatures with- a terrestrially-adapted egg. So reptiles, mammals and birds. Other vertebrates have different numbers.

So perhaps pigeons really see magnetic direction and topography. Maybe, just maybe, it’s superimposed upon, and integrated with, the already-unbelievably-fantastic octochromatic visual image the bird has of the world. An image more detailed, more comprehensive, more sophisticated and perhaps more beautiful than anything we can ever even imagine.

pflight1 When released far from home a homing pigeon circles the release point a few times, presumably getting its bearings, before flying off on an initial heading within a degree or so of home. I like to think about the image the bird must see as it circles, the little ah-ha moment it must experience as it aligns its world-view with its mental map and aims for home.

So. Are you starting to see how Pigeons might be way cool yet? Let me tell you what- we are just getting started.

Next Up: Gender, Souls and the Parallel Evolution of Milk.