Blackpoll Warbler
It was a busy week for banding birds, like this Blackpoll Warbler, at David's study site in Tennessee. These warblers are tiny, active birds returning from wintering grounds in Puerto Rico, the Lesser Antilles, or northern South America. Their route averages 3,000 km (1,864 mi) over water, and could have meant a nonstop flight lasting up to 88 hours!

Image: David Aborn