An extraordinary feat of migration has been confirmed in a tiny songbird that weighs just 12 grams.

Blackpoll warblers (Setophaga striata) have long been thought to fly non-stop from northeastern North America to the Caribbean or South America. William DeLuca of the University of Massachusetts, Amherst, and his colleagues fitted the birds with 0.5-gram devices that record light levels over time, allowing latitude and longitude to be inferred from the date and the timing of dusk and dawn. Five birds were successfully recaptured, and the data suggested that the birds flew in a straight line over the Atlantic Ocean to the Caribbean, where they made a stop before continuing to wintering grounds in South America.

The journey required three days of non-stop flight and covered some 2,500 kilometres — one of the longest-recorded migrations for a bird of its size, the authors say.

Biol. Lett. (2015)