The field season is mostly over. My field assistants are back in classes; my mist nets are packed away. (Many thanks to the people who kept us fed and equipped by donating a total of $1450 to this field season!) It’s grant-writing, lab work, and data analysis season now.
Well, almost. I really want to know what the juncos do when summer ends. Our working assumption is that they migrate down the mountains to escape the worst of the winter weather, but we don’t know how far they go, or when, or, really, if they do that at all. So this week I went back to look for them.
SOSA, photographed on his territory earlier this year, was nowhere to be found. Photo by M. LaBarbera.
I’m quite behind in my bycatch* posts! All of the birds in this post were caught several trips ago.
*Bycatch: birds that fly into our nets while we are trying to catch juncos. We extract them from the net, take a few photos, and release them.
Female Brewer’s Blackbird:
I am too zen to be bothered by you, giant pink monster
Almost all birds incubate their eggs: keeping them warm while the embryo develops into a chick. In order to transfer heat better from their body to the eggs, many birds develop brood patches (a.k.a. incubation patches). The bird loses feathers from her belly, and the bare skin becomes wrinkly and swollen with fluid. In juncos only the female develops a brood patch, since she does all the incubating, but in species where males also incubate, males can develop brood patches too.
White-crowned Sparrow with a brood patch that is beginning to show edema