<a href="https://en.wikipedia.org/wiki/Common_Nighthawk" class="extiw" title="w:Common Nighthawk">Common Nighthawk</a> (Chordeiles minor) in <a href="https://en.wikipedia.org/wiki/Dakota_City,_Nebraska" class="extiw" title="w:Dakota City, Nebraska">Dakota City, Nebraska</a>.  The bird was photographed at about noon on a hot day (about 80 degrees F, or about 26 C).  It was sitting on a crushed-rock pavement at ground level, in full sun.  The throat was vibrating; presumably, <a href="https://en.wikipedia.org/wiki/Thermoregulation" class="extiw" title="w:Thermoregulation">gular fluttering</a>.
<a href="//commons.wikimedia.org/wiki/User:Ammodramus" title="User:Ammodramus">Ammodramus</a>
2010-07-09
<span class="int-own-work" lang="en">Own work</span>