I have two easy anatomy terms for you this morning.

The side of a bird is on the side of its breast.  Here’s a female chestnut-sided warbler, with chestnut colored sides.  There used to be a bird called a rufous-sided towhee but it was renamed to “eastern towhee.”   He still has rufous-colored sides.

The flanks of a bird are on the sides of its lower belly. Here, a tufted titmouse illustrates this body part by showing off its rusty-colored flanks.  Titmice are white underneath except for this rust color which matches the brown dead leaves that hang on beech trees in winter.  I’ve read that this color helps camouflage the titmice.

(Chestnut-sided warbler photo by Chuck Tague. Tufted titmouse photo by Marcy Cunkelman. Both photos are altered to illustrate anatomy.)