Cerulean Warbler <i><a href="//commons.wikimedia.org/wiki/Setophaga_cerulea" title="Setophaga cerulea">Setophaga cerulea</a></i> female on nest, Lost Valley, Weldon Spring Conservation Area, Missouri.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/80270393@N06">Andy  Reago</a>
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/wildreturn/8414744059/">Cerulean Warbler - nesting</a>