The lower surface of the body, including the chin, throat, breast, belly, sides and flanks, and undertail coverts, and sometimes including the underwing surface and the underside of the tail [1].
References[]
^Bellrose, Frank C. and The Audubon Society (1983). The Audubon Society Master Guide to Birding. National Geographic Society. ISBN1426200722.
This article is part of Project Glossary, an All Birds project that aims to write comprehensive articles on each term related to animals.