12 February 2010:

If you thought we were done with bird anatomy because we reached the tail last week, think again. 

There are plenty of obscure anatomical words that I haven’t covered yet.  For instance, what about axillaries?

Axillaries are the bird’s armpits, circled above in yellow.  Usually they’re unremarkable because they’re a single color but every once in a while there’s a surprise. 

For instance, notice the American robin above and the black-bellied plover below.

And how about this illustration of rose-breasted grosbeaks? Who knew that the males have rosy armpits and the females have yellow?

If birds don’t soar, we get only a fleeting glimpse at their axillaries.

(photo credits: American robin by Marcy Cunkelman, black-bellied plover by Chuck Tague, rose-breasted grosbeak illustration from Wikimedia Commons; click on the caption to see the original)