"You’ve likely seen them. Barn swallows live across the Lower 48 where they build mud nests under bridges and overhangs and in – you guessed it – barns. They streak through the air in the early morning and late evening scarfing up flying insects by the hundreds.

Very few overwinter in the U.S. Most barn swallows migrate through Mexico and Central America down to Argentina and Chile.

And in an interesting turn of evolution, some started to stay in South America where they are taking advantage of increased infrastructure.

“They live in culverts and the latitude south of the equator is the same as north of the equator,” Iliff says.

Something allowed the birds to switch, and those that breed in North America overwinter in Argentina at the same time as others breed in Argentina and overwinter in Brazil."
blog.nature.org/science/2018/03/06/four-impressive-bird-m...

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Make:	Canon
Model:	Canon EOS 80D
Exposure:	0.001 sec (1/1000)
Aperture:	f/14.0
ISO Speed:	5000
Focal Length:	400 mm
Lens:	EF100-400mm f/4.5-5.6L IS II USM