Every autumn, the blackpoll warbler (Setophaga striata) flies nonstop from Canada or New England south across the Atlantic Ocean and lands on the northern coast of South America three days later. In that time, the 12-gram birds travel 2,270 to 2,770 kilometers, and theirs is one of the longest transoceanic flights recorded in a songbird, researchers report April 1 in Biology Letters.
Plenty of circumstantial evidence had pointed to an impressive migration in blackpolls. In 2013, researchers equipped the birds with tiny geolocation devices that use sunrise and sunset times, which vary with latitude, and modeled the birds’ calorie intake and energy expenditure to confirm that the birds’ bodies could physically make the journey. Why exactly the blackpoll travels such a dangerous route remains a mystery.