Northern Rough-winged Swallows (Stelgidopteryx serripennis) - These are common swallows where I'm from in Central Arizona, so it was interesting to record them in Costa Rica, too - they sound pretty much the same!
Northern Rough-winged Swallows (Stelgidopteryx serripennis) reel in the Spring air above Tavasci Marsh [Arizona], calling as they fly - notice, as in most swallows, that they call most when the flock is the densest (a mechanism to help avoid collisions?).
Northern Rough-winged Swallow (Stelgidopteryx serripennis) is a small swallow. These birds forage in flight over water or fields, usually flying low. They eat insects. 'Rough-winged' refers to the serrated edge feathers on the wing of this bird; this feature would only be apparent when holding this bird.
