Monthly Archives: April 2012

Scouting Sierra—or not

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I had planned to visit Sierra National Forest as well as Stanislaus; but it turned out that Sierra was more closed (due to snow) than I expected. The few campgrounds open were in a very heavily built-up area, lots of gated estates and resorts. I was torn: I wanted to scout Sierra, but this was clearly not the part of Sierra I would be working in.

On the other hand, the first Stanislaus campground I had visited seemed like a likely site for future field work, and I had seen a junco there. Just one; but I knew he was there. If I went back I could try to resight him, observe him, and try to figure out what breeding stage he was at. In the end I decided to do that, so I headed back for Stanislaus.

On the drive I saw another pair of Western Bluebirds and a jackrabbit.

Please don't pull over to look at me

I also saw some non-wild fauna.

The ovine breeding stage scientifically known as the "adorable" stage

Featured paper: fledging House Wrens are funny

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(This will be a regular feature: blurbs about papers I like.)

Today’s paper: “The process and causes of fledging in a cavity-nesting passerine bird, the House Wren (Troglodytes aedon)” by L. Scott Johnson, Robin L. Rauch, and Sara N. Dellone. Published in 2004 in Ethology 110, pages 693-705.

Fledging is the act of leaving the nest for the first time. In birds with altricial (helpless, naked, dependent) young, this is a big step: the chicks go from sitting in a nest to flying around like adult birds. Or trying to fly around, anyway. Fledglings often aren’t very good at flying at first.

A rehabbed House Wren nestling (and messy eater) nearly ready to fledge

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Fitting a bird-shaped peg through a tiny hole

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Bird wings come in a variety of shapes, from long and slender to short and rounded. These shapes affect how good the bird is at different types of flight: long and slender wings are good for soaring, while short and rounded wings are good for maneuverability.

House Wrens spend a lot of time flitting around in dense brush, so they need to be very maneuverable.

Short, rounded wing of a House Wren

(They don’t usually hold their wings that way – this was an injured bird I was caring for – but it’s the best wing-shape picture I have.)

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Field season 2012 starts… now!

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I’m heading for the field today! As soon as I find my GPS, or give up on finding it…

This is a scouting trip. I won’t catch any birds (I don’t have the state permit for that yet anyway) but I’ll try to find them, see what breeding stage they’re at, and figure out what sites will be the best to focus on. I’ll start out in Stanislaus National Forest, then head to Sierra National Forest. It’s early enough in the season that most campgrounds are still closed, so I don’t get much choice of where to stay, but I’ll cover as much ground as I can. I’m hoping there won’t be many road closures in the parks but you never know.

I’ll be back Friday. In the meantime, I’ve scheduled posts (I’ll be “posting from the past,” as Jim Hines put it), and here is a picture of a marmot relaxing:

Angry birds

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Not the game—real angry birds. You may not always notice angry birds, but they are all around you. Birds mob other (usually larger, threatening) birds, flying at them and even hitting them. Imagine if mice got together to run headfirst into cats…

(Actually, I know some cats that might be scared of those mice. You might call them scaredy-cats… Don’t hurt yourself laughing at my witticisms.)

Birds also fight others of their own species. Physical fights are pretty rare: birds usually try to work their fights out using “words not fists”—or rather, song not violence. Birds will usually start with songs and calls, then escalate to threatening postures and movement, and only if none of that resolves the issue will they fight. Recently, I watched a Snowy Egret face what I think must have been an intruder on his territory. First he called. When the intruder didn’t leave, he raised the crest on his head high and flew at the intruder, chasing him away. Continue reading →

Follow-up: almost nobody understands mirrors

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Since several people have contacted me to defend junco intelligence after the mirror post yesterday, I thought I might talk a bit more about birds and mirrors.

Very, very few species understand mirrors, and an enormous majority of them behave as if the mirrored images are real, as the junco did. The list of birds that do not recognize themselves in the mirror is long: Budgerigar; House Sparrow; Kea; Black-capped Chickadee; Zebra Finch; Cedar Waxwing; Glaucous-winged Gull; Blue Grouse; Peach-faced Lovebird; reviewed in (1). In 1964, Edith Andrews kept an injured junco in a cage with a mirror and observed that it was quieted by the mirror, liked to perch next to it, and “appeared to be smitten with its own image” (2).

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