I have family in town this week, so between work and family-visiting type stuff I won’t have time for any more “serious science*” posts this week. (Pic right = Twin A after being kissed by multiple visiting female relatives.)
*I recognize that calling any of my posts “serious science” is a bit of a stretch; what I really mean is “posts for which I have to look stuff up.”
But so much is happening right now that I don’t want to skip another day, so forgive me for doing a fairly “lite”/observational post today.
This is a great time to be paying attention to the bird-feeder in your backyard, and here’s why: Let’s say you have a group of a few friends with whom you get together to do something every week. For me, that’s mountain biking on Tuesday nights in the summer, but for you maybe it’s getting together to go running or skiing or knitting, or watch “Law & Order” (Christ I hate that stupid show.) But whatever it is, it’s a habit, and you do it, but if something comes up to take you away from it one day/night/week it’s no big deal because you see all those friends every week.
But if an old friend you don’t see very often was passing through town and was going to join you on Tuesday night to bike/ run/ ski/ knit/watch a lame TV program, you’d probably make an extra effort to show up that Tuesday, because it’s so rare that you get to bike/run/ski/knit with that old friend. (Pic left = actual old friend I haven’t seen in 11 years for whom I would definitely change my plans to see if he were in town.)
That’s exactly how it is at your bird feeder right now. For months and months and months, the same half or so dozen birds show up at your feeder. But then, right around the end of March, new birds start showing up. And more new birds keep showing up over the next couple of month. But many of these new birds don’t stick around; they’ll hang out for a couple weeks or maybe just a couple of days, and then they move on.
What’s more, these new birds- as well as some of the old Winter birds- start singing! They’re singing in the morning, they’re singing in the evening, they’re chirping in the afternoon. In other words, there’s big party going on in your back yard right now, with a bunch of faces you haven’t seen in months, and will only be around for a couple days/weeks, so you better pop your head out back and make sure not to miss it.
Tangent: What? You don’t have a bird feeder? You’re not into birds? What are you, some kind of joyless robot? Live a little! Get a feeder! It’s the easiest wildlife-viewing experience you’ll ever know. Just hang a cheap feeder from a branch, fill it with a bunch of seed, and – voila!- you’re a regular Avian Marlin Perkins!
The Plot So Far
We’ve seen some cool newcomers over the last couple of weeks, but first I feel I need to catch up on what’s been happening at my feeder over the last 3 months, since I did the “Bird Feeder Week” series.
The biggest development was this- sometime in the last 90 days, when I wasn’t paying close attention, a pack* of Pine Siskins, Carduelis pinus, completely took over our primary feeder. These little guys, whom I initially mistook for female House Finches, are tough. They actively drive other birds away from the feeder, as well as each other, and there’s one member of the flock- the alpha-bird- who has zero tolerance for any other bird perching on the feeder at the same time (with one exception, which I’ll get to in a moment.)
*Yes, I know birds run in “flocks”, not “packs”, but these guys are so mean I call them a “pack.”
Speaking of Pine Siskins and House Finches, here’s an interesting difference between the 2: Back at the end of Bird Feeder Week, I blogged about the Brown-Headed Cowbird (BHCB) (pic left), which is a brood parasite, sneakily laying its eggs in the nests of other species, who end up raising the BHCB chicks. In that post I explained how the House Finch is such a lousy target for the BHCB; they lay their eggs in House Finch nests, but virtually none of the BHCB chicks survive, the reason being the lack of protein in the all-vegetarian diet fed by House Finches to their chicks.
Well, unlike the House Finch, the Pine Siskin is an excellent and very productive target for the BHCB. Although Pine Siskins are primarily vegetarian, they add insects to their diet in Spring and Summer, and in particular they feed insects to their chicks. The seasonal protein boost is enough to support a BHCB chick, and Pine Siskin populations have suffered as a result.
BHCBs and Pine Siskins have both been in North America a long time, but European settlement has brought them in closer regular contact. BHCBs are native to plains/grasslands, while Pine Siskins are native to forests. But both take readily to the to the semi-open woodlands created by modern settlement (think suburbs) and as a result the 2 species cross ranges much more extensively than in pre-settlement times, to the BHCB’s benefit and Pine Siskin’s detriment.
First, it is way good looking. The feather-color pattern is cool enough, but the black head, back beak and orange eyes give it a way-cool look. Kind of like if a Robin went to a high-end salon and got a really killer makeover.
Second is its funky ground-hop. It spends a lot of its time on the ground under the feeder, scratching around for insects. And it does so with a 1-hop-forward, 2-hops-back gait over and over again.
Third is its toughness. When it does get up on the feeder, it is the one bird that won’t back down from the Alpha-Siskin. It doesn’t start fights, but when the Siskin goes after him, he comes right back at him, never backing off.
And fourth is the cool ongoing story of its sort-of-speciation from the closely-related Eastern Towhee, Pipilo erythrophthalmus (pic right). The 2 species diverged sometime in the recent past, but are closely-related enough to easily interbreed. (In fact until about 15 years ago they were considered the same species.) Historically their ranges have been separated by the Great Plains. But Euromerican settlement has introduced large “forest islands” to the Plains (towns, suburbs), enabling the Eastern Towhee to expand its range westward, coming into contact with its Western cousin, and today the two frequently hybridize.
But here’s the cool thing about this story. Back in April – June of last year (way before anyone read this blog) I told this same exact story with 3 different bird-pairs: Stellers Jay/Blue Jay, Lazuli Bunting/Indigo Bunting, and Black-Headed Grosbeak/ Rose-Breasted Grosbeak. In each of these cases, an ongoing, partway-there speciation process is in the process of being possibly being altered or even derailed due to hybridizations made possible by human settlement, and alteration, of the Great Plains.
These aren’t textbook-theory-what-if scenarios; these are real, evolutionary processes and changes in action that have happened- and are continuing to happen- over just a few human generations. The more you get to know about birds in North America, it’s simply amazing the impact humans have had on them.
Tangent: There are actually ~9 species of Towhee in North America, and the details of their family tree have been the subject of much research and are still not entirely clear. But that’s a topic for another post.
Speaking of impact, another dramatic way people have changed the avian fauna of North America is through introductions, the 3 most obvious examples being the Rock Pigeon, the European Starling, and the European House Sparrow, Passer domesticus (pic left), the last of which has also started showing up more regularly to our feeder over the last 60 days.
Side Note: Though a recent arrival to our feeder, P. domesticus is a very common winter bird around the Salt Lake Valley, and in fact it is the dominant bird throughout the strip mall next to my office (the “Family Center” in Midvale.)
EH Sparrows were introduced in several separate East-coast events in the mid-1800’s. The motivation for the introductions was pest control, but the Sparrows themselves soon became the pests; they quickly expanded across the continent. They’re aggressive, and actively harass and evict other birds, such as Bluebirds and Purple Finches, from existing cavity-nests, smashing eggs and even killing adult birds in the process.
Tangent: From what I understand their introduction to Australia has been even more destructive; they’re a common pest in the Eastern half of the continent, and supposedly any EH Sparrow found in Western Australia is deliberately killed. I believe the original motivation for the Australian introduction(s) was also pest control.
Speaking of motivation, the European Starling wasn’t introduced* to North America until 1891, and the reason for the deliberate introduction was- get this- a group called the American Acclimization Society whose mission was to introduce to the New World all of the birds mentioned in the works of Shakespeare. I am not making this up. Talk about a bizarre hobby.
*Successfully introduced, that is. There were multiple earlier attempts.
Wait- What Am I Doing?
Wait a minute. This was supposed to be a “lite” post. But I’m already at 1400+ words, with graphics, tangents, a (sort-of) map and references to previous posts… What is wrong with me? Why can’t I do a short post? I see other people’s posts all the time, and they’re like:
“JP came over. We had a beer and saw some brown birds in the backyard. Then we ordered a pizza. Good times.”
And that’s like the whole post, and there’ll be like 20+ comments saying stuff like “Great post!” or “Sounds like you and JP killed it!” But no matter how hard I try, every one of my posts turns into some run-on-science-deep-ender. I swear, sometimes this blog reads like a cry for help…
While I’m on the topic of run-on posts, 2 readers- let’s call them “My Coworker Kelly” and “My Sister Elizabeth”- told me within the last week that they only read this blog for the tangents. They skip over all the science stuff and look for the colored sections where I go on about the Greek Church, or Phil’s lame bands or Ricardo Montalban. So before I go any further, I guess I’d better give them a tangent.
Tangent: I finally broke down and got a Blackberry this week. I resisted as long as possible, and then delayed the process a few more weeks by dithering between the Blackberry and the iPhone. I have colleagues with both, and checked them out, asked their opinions, and fooled around with each (device, not colleague.)
I picked the Blackberry for a couple of reasons, partly for the keyboard, partly for the lower weight (remember, I bike with it) but most of all because I was so turned-off by the cult-like proselytism of the iPhone users. It’s like every new iPhone user feels this bizarre need to validate their purchase decision by turning into a virtual Apple sales rep. Whatever you’re talking to them about, they’re just waiting, waiting, waiting for an opening to whip out the iPhone. When you talk to them about something- a project, a trip, your weekend, whatever- they’re nodding along like “uh-huh, uh-huh…” but you can tell they’re not listening. No they’re just thinking, “Please, please let him ask me where the best place is in Indianapolis to get organic sushi so I can show him on my iPhone…”
The most annoying feature they’re always demoing is the GPS. You go out to lunch, and they’ll say, “Let me just look it up on my iPhone…” and you’ll be like, That’s OK it’s down the street, it’s the same place we always go for fish tacos… but they’re already doing that bizarre origami-schtick with their fingers on the touch screen. Or you’ll tell them you’re running an errand, and they’ll ask where, and you’ll say, Oh it’s over on 700 East and 90th South, and they’ll be like “Let me just look it up on my iPhone for you…” and you’ll be like, No it’s OK, Salt Lake is on a grid, I can figure it out… Seriously the addressing system in Salt Lake- which is based on a very sensible numerical grid- is the easiest address system to navigate anywhere. If you can’t find your way around Salt Lake City without a GPS, you don’t need an iPhone- you need a Seeing-Eye Dog.
New Birds On The Block
OK, so that’s what happened at the feeder over the last 60 days. But now, over the last 2 weeks, new birds have started showing up- birds we haven’t seen since last year! Early last week a pair of Western Tanagers (pic left) appeared and spent an afternoon before moving on (blogged about them last year in this post) and on Sunday a male Red-Winged Blackbird, Agelaius phoeniceus, showed up for a day or so. RW Blackbirds are cool because they’re good looking and because they have the coolest call. You hear them all the time around in and around wetlands, but they’re unusual in our yard.
When you hear a male RW Blackbird calling, guess what it’s probably doing? Warning off other males. A. phoeniceus is highly polygynous, meaning one male breeds with many- up to 15- females, each of whom maintains a separate nest. The male jealously guards access to all his “wives” from other males, and it’s estimated that a male RW Blackbird spends roughly 50% of daylight hours warning/chasing off other males.
But what’s really interesting about this “harem-guarding” behavior is that it’s only partly effective; biologists have tested the paternity of A. phoeniceus chicks, and somewhere between ¼ and ½ of all chicks are fathered by other males, who successfully “sneak-mate” with the females.
The mating systems of different animals are always fascinating. And at a gut level, most human males- whether or not they admit it- certainly “get” the appeal of polygyny. But the more I learn about actual, real-world, polygynous mating systems, either animal or human, the more it sounds like a monumental pain in the ass. That reminds me: I need to pick up some flowers for Awesome Wife on the way home today.