Party at My Place!

No, no, no! I’m not inviting you to a party at my place. I’m telling you about the party that is already happening at my place. The month+-long crazy bird-feeder party that happens every May/early June. The party is in full swing right now, and the principal partiers are- yet again- the Lazuli Buntings, Passerina amoena.

Tangent: Speaking of parties, it’s interesting how they change as you get older. When I was young and lived in a house with a bunch of guys, we hosted fairly frequent parties to which we invited pretty much everyone we knew. The preparation was minimal- lots of beer and chips- and the cleanup straightforward- walk around the house and yard with a couple of garbage bags.

Nowadays, parties are way different. Specifically, we only host them when AW gets it into her head that we should “entertain*.” And then they involve all sorts of preparation like fancy dips and color-coordinated napkins and what-not, and not a small amount of discussion around whom to invite and who will get along with whom. If it were left up to me, I’m not sure we’d ever host any event more sophisticated than sitting on the porch and ordering pizza, but there seems to be some primordial female nesting instinct that manifests itself in periodic interior redecorations and biannual grown-up-parties.

*Why do we use that word- “entertain”- when hosting parties? It’s not like we’re singing or tap-dancing or playing the ukulele for our guests. We’re just giving them food and drinks and maybe playing some chick-tunes** for them.

**Because that’s the other big change when you get married and start having grown-up parties- your wife picks the music. I’ll walk away from the stereo for a few minutes as she’s getting ready for the party, and when I get back the room is filled with the whiny, emotionally-overwrought, soporific strains of Sean Colvin and the Indigo Girls, my Pavement and Big Dipper CDs nowhere to be found…

Of course, I’m not pining away for the parties of my youth either. Though they were fun, I have no desire to repeat them. Part of this may just be my getting old and boring, but upon reflection, I can think of at least 3 other reasons why this should be:

1) I have nicer stuff now, which I don’t want to get wrecked.

2) I’ve already met most of the people I want to meet. Seriously, I can barely remember the names of my current friends, what with my low Dunbar number and all. When you’re 20, you’re like, “Hey, I can’t wait to meet some new people…” When you’re 45 you’re like, “Don’t make me remember any more names…”

3) OK here’s the real reason. The reason why young men host- or attend- parties is that they are hoping to “hook up.” That’s it. That’s the only reason. By hosting a huge keg party and inviting everyone they know, young men are hoping that their friends will bring along other friends, and friends-of-friends, some of whom will be attractive young women. As a result, later in life, we’re always a bit surprised when our wives suggest hosting a party. “What for? I’m already happily married*…” is our first thought.

*“And half the point of getting married in the first place was so I wouldn’t have to go to parties to try to meet women anymore…”

Back to The Post

Here are 2 milestones for me. First, 2010 is the 3^rd year I’ve paid attention- really any attention at all- to which birds show up at our backyard feeder. And second, today marks the 34th consecutive day we’ve had Lazuli Buntings at our feeder.

In 2008 we had 3 male Lazuli Buntings show up in our yard and hang out there for about ~3 weeks. I wasn’t diligent about noting the exact dates.

In 2009 we had either 5 or 6 males and 3 or 4 females show up promptly on May 1, and stick around for exactly 23 days. About 2 months later, in late July, a solitary male showed up for just one day. Why he was there and where he was going I can’t say, but I got the sense things weren’t going according to plan for him, and that he was in a hurry to catch up.

This year we had at least- at least- 10 Lazuli Bunting males and at least 6 females show up on May 5, and at nearly 7 weeks, they’ve never stuck around longer. As they did in the previous 2 years, they quickly established near-total dominance at the feeder, tolerating only the occasional House Sparrow.

Side Note: Their dominance-establishment wasn’t as immediate, smooth or total as the previous years, however. For the first few days of their arrival, a male and female Black-headed Grosbeak pair also showed up (pic right = male), and these larger birds gave the Buntings a tough go of it for a couple of days.

I still see the BH Grosbeaks all the time, only a mile or 2 from my house. They’re common in the scrub oak around 5,500 – 7,000 feet right now, and you can hear them singing* at dawn out on the Shoreline trail, or up a little higher around Jeremy and Pinebrook.

*Both males and females sing, 1 of 4 really cool things about BH Grosbeaks I covered in this post.

But the Grosbeaks soon disappeared from our yard, leaving it to the Lazulis.

The Lazulis are eye-catching birds (the males anyway), fun to observe, and we look forward to their arrival each Spring. Having watched these guys, and noticed the trends in dates and a numbers over the past 3 years, I wonder: Where do these guys come from, where are they going, and how come there are more of them each year?

Lazulis are migrators, wintering down in Western Mexico, along the Pacific coast. In fact the Bahia de Banderas (Puerto Vallarta) is pretty much the dead center of their wintering grounds. Though I didn’t spot any when we were down there the first week of April, it’s possible they’d already left, and were en route to Utah, and other parts North, when we visited.

Their summer breeding range encompasses most of the Western US, from Northern Arizona and New Mexico up to extreme Southern Alberta, BC and Saskatchewan, from Western Nebraska to the Pacific Coast, and they follow 2 main flyways Northward once they cross into the US. The first runs up the Sierra Nevada up through California to Washington and BD, while the other goes along the spine of the Rockies. They favor more open woodlands and forests, which in much of the West means pine forests, and as don’t remain the whole summer to breed in our yard they’re obviously moving on, but to where I’m not quite clear. Is the final leg of their migration from our yard primarily one of latitude or altitude? Meaning, are they just pit-stopping out our house till things melt out, and then going up into the nearby mountains to nest and breed? Or are they continuing on North into Idaho, Montana, etc.?

I’ve never noticed Lazulis higher up in the Wasatch in summer, but I can’t say that I’ve diligently searched for them, either. We have plenty of PLT forest in the Wasatch, but no pine forests*. Do they also nest in Fir and Spruce forests? The literature doesn’t say. But if true pine forest is where they’re headed, they wouldn’t find it in the Wasatch, and that makes me suspect that they’ve got another big leg of their migration still ahead.

*A subject that still fascinates me, and which was the subject of this post. Really, it’s one of the most interesting things about the Wasatch…

The increasing annual numbers of them at our feeder are interesting, suggesting 2 possibilities. The first is that hangers-on are this year accompanying the original core group. The second, and more encouraging, possibility is that some number of this year’s visitors are the descendants of the 2008/2009 visitors, and that the group represents in part a growing, extended family.

In either case, it’s quite likely that some members of the original 2008 migrants are in our yard right now, but interestingly, the males are likelier to be repeat visitors than the females. Lazulis live up to 11 years in the wild, and often return to the same summer breeding grounds. First-year males return to the same breeding site 71% of the time, and males 2 or older return to the same spot 87% of the time. But females changes sites much more frequently from year to year, with only about 56% returning to the same site. (Females may be a bit likelier to return to a site if they bred there successfully the previous year.)

If the “family” is growing, and spending more time at our “stopover”, it suggests that our filling the feeders is having a small but real impact on the destinies of some modest numbers of birds. And if some decent percentage of the million+ suburbanites across the Salt Lake Valley…. Well, it makes you wonder how much backyard birders are influencing the course of songbird evolution.

Human impact on Lazulis isn’t all positive of course; they’re one of the many species who’ve suffered from the brood-parasitic behavior of the Brown-Headed Cowbird, whose range has been greatly expanded over the last century by human agrarian and suburban development. But on a local level, it cheers me that our feeders may be helping these guys out.

We’ve never seen Lazulis in the Fall, nor- with the one exception above- any later than June. But they do make a substantial stopover on their return migration, usually in Southern Arizona, Northern California, or Southern Baja*. And what’s interesting about this stopover- and highly unusual among songbirds**- is that during this stopover, they molt.

*For a long time it was thought that Lazulis over-wintered in Baja, but they don’t; it’s just a stopover for them.

**Though not for many waterfowl, who often molt at stopover locations.

Birds molt for mainly 2 reasons: to change their appearance and to replace worn feathers. Birds change their appearance to indicate sexual maturity or receptivity, as well as to avoid predators. When adult Lazulis molt during their stopover, their replacement feathers are buff-tipped in such a way to damp out the intensity of their colored plumage (which makes sense for the non-breeding/winter season ahead.)

Wing feathers- both primary and secondary- take a beating*, and need to be replaced. Re-growing major feathers is a big deal- rather more resource-intensive than growing a new coat of hair, for example. It’s been estimated that the basal metabolism rate of a bird goes up anywhere from 9 – 46% during molt, reflecting the huge caloric expenditure involved in growing new feathers.

*As non-flyers, we don’t think about how hard flying is on the wings. With honeybee workers for example, wing-life more or less equals life-span. When her wings start to give out an older worker generally “retires”, or is retired, from the hive.

The question is why Lazulis molt during the stopover? Why not just molt either in their summer breeding grounds, or down in the wintering grounds, as do their cousins, the closely-related Indigo Buntings, P. cyanea? Lazulis aren’t the only Passerines who interrupt migrations to molt; Bullock’s Orioles, Icterus bullockii, and Painted Buntings, Passerina ciris, do similar stopovers in the same areas. One hypothesis is that Southern Arizona, Baja and Northern Sonora see a brief seasonal boost in plant and insect food supply following late-summer monsoon rains. But since Lazulis usually stop over in riparian areas anyway*, it’s not clear how much of a monsoonally-induced boost food supply they’d actually see.

*Actually, these days it’s either riparian or irrigated agricultural areas, but I assume the stopover behavior predates large-scale agricultural irrigation in the border region.

The stopover-migration-molt may explain something else about Lazuli- and Indigo- Buntings. 2 years ago, in my original post on Lazulis, I mentioned that where their ranges overlap, Lazulis and Indigos will sometimes interbreed. One of the questions about these birds, since they don’t seem that reluctant to breed together, is why there aren’t more Lazuli x Indigo hybrids around. Migration-molt patterns may provide a partial answer. Lazulis stopover to molt, but Indigos don’t molt until they reach their Central American wintering range. It may be that hybrids are stuck in a molting no-man’s land, disrupting their migrations, possibly stranding them, and lowering their chances of survival.

In any case, it makes me happy to think that I’m seeing some Lazulis I’ve seen before, and that I’ll likely see some of the same guys next year. Though I can’t distinguish them individually, I wonder if they recognize me?

Then again, maybe the beard threw them off this year.

Note about sources: Info on migration and molting patterns on Lazulis Buntings, Bullock’s Orioles and Painted Buntings, as well as basal metabolic info while molting, came from this paper by Bruce Young of the University of Washington. As always, I am extremely grateful to researchers who make copies of their research available online to motivated laypeople. Info on rate of return to breeding locations and other helpful info came form this page. Additional info was provided by the Cornell Ornithology Lab public site.