I just double-checked my reference shelf. The field guides (Peterson's and Audubon Society) capitalize names in running text, but Peterson also prints names in ALL CAPS both at the head of the entry and on the pages with the illustrations. It looks more like a design choice than an editorial one. (I should also admit that I'm skeptical of using, as an authority on English spelling/capitalization, a volume that consistently spells "juvenile" "Juvenal".)

The Audubon Society Encyclopedia of North American Birds lower-cases species names.

I don't know if this reflects a recent tendency among birders to capitalize for clarity, or a difference between field guides and references that you're expected to use at home.

Does anyone have Sibley's? (It's more recent than any of my references, and I mean to buy it when I can afford to.)

As a side note, I both write and copyedit Wikipedia entries, and wrote the entry on the red-winged blackbird.

Wikikarma: random copyediting last night.