Brown-chested martin

The brown-chested martin (Progne tapera) is a species of passerine bird in the swallow family.

It is found in Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, French Guiana, Guyana, Panama, Paraguay, Peru, Puerto Rico, Suriname, the United States, Uruguay, Venezuela, and is a vagrant to Chile and the Falkland Islands. Its natural habitats are dry savanna, subtropical or tropical seasonally wet or flooded lowland grassland, rivers, and heavily degraded former forest.

It usually swoops at low heights, showing white on the sides of its tail, with wings bowed. It may dig burrows into banks to nest (or occasionally in snags) or sometimes use old hornero nests.

Diet
It eats insects, especially termites and winged ants.

Social Behavior
It often congregates in groups of up to tens of thousands around dusk.