Why birds don’t need GPS

Imagine you’re an albatross, a large seabird that spends months aloft over the open ocean. Now it’s the breeding season: time to head back to your favorite island, do some amusing courtship dances, and lay an egg. But you’re in the middle of the vast, featureless open ocean. How do you find your way back?

Homing pigeons, taken from their roosts and driven up to 800 km away, can fly home. (Several pigeons have received the animal version of the medal of honor for doing this while carrying messages in wartime.) Arctic shorebirds like the Red Knot will fly from the Arctic to southern South America, over 13,000 km, twice a year. Birds are very good at navigation. How do they do it?

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A conference, a love story

A conference, a brief vacation, and getting back into non-field-work have conspired to keep me away from the blog for far too long; humblest apologies!

Red-breasted Nuthatch scoffs derisively at your apology!

The conference was the North American Ornithological Conference, which combined the usually-separate annual meetings of many ornithological societies into one gigantic über-meeting with 1500+ attendees, almost all of whom were presenting their research as either a talk or a poster.

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Featured paper: barn owl chicks’ spots

Melanic color-dependent antipredator behavior strategies in barn owl nestlings. By Valentin van den Brink, Vassilissa Dolivo, Xavier Falourd, Amélie N. Dreiss, and Alexandre Roulin. Behavioral Ecology, 2011.

I’ve been slacking off on the Featured Papers, since it’s the field season and I’ve been reading almost nothing less than usual; but this paper is too crazy not to mention.

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Where’s the research?

You might—or, by this point, might not—recall that I’m supposed to be doing research that will be the basis of a PhD here. Based on the actual content of the blog, you’d be forgiven if you thought that the point of all of this was to take photos of various annoyed birds held in the photographer’s grip.

Go away! I am not a PhD!

So where’s the research part?

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Featured paper: nest predation

Corey Tarwater. 2008. Predators at nests of the Western Slaty Antshrike (Thamnophilus atrinucha). The Wilson Journal of Ornithology, volume 120(3): pp 620-624.

Nest predation is a major worry for most birds. Chicks in the nest are essentially helpless, and parents usually can’t do much to stop predators, although they will try. Losing broods to predation is common. In this study, 79% of nests were lost to predation. If you’re a Western Slaty Antshrike, you can expect 4 out of every 5 broods of chicks you have to get eaten!

Yet actually seeing these—or any—predation events is extremely rare. Dr. Tarwater describes five nest predation events on Western Slaty Antshrikes (small, cryptic brownish birds) in Panama, one she observed in person and the rest of which she caught on video.

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Featured paper: fledging House Wrens are funny

(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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Follow-up: almost nobody understands mirrors

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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