Songbird's 'fly-or-die' marathon

The birds were fitted with miniature electronic backpacks. Photo / AP

Study finds tiny warbler migrates up to 2770km over open ocean.

A small songbird no bigger than a sparrow flies up to 2770km over open ocean in a non-stop flight in what has been described as one of the "most extraordinary migratory feats on the planet", a study has found.

Scientists said the annual open-water flight of the tiny blackpoll warbler from the northeast corner of North America to the forests of South America is one of the greatest migratory journeys.

It was thought that the songbird, which spends summer in Canada and the US before heading south for the winter, flies overland down the eastern coast of America, stopping on its way to rest and feed.

However, a study involving miniature electronic backpacks to monitor the birds' movements has revealed that the blackpoll warbler flies due south over open water in a "fly-or-die" journey until it reaches landfall in the Caribbean two or three days later, before flying on to Venezuela and Colombia.

"We're really excited to report that this is one of the longest non-stop flights over water ever recorded for a songbird, and finally confirms what has long been believed to be one of the most extraordinary migratory feats on the planet," said Dr Bill DeLuca of the University of Massachusetts Amherst, the first author of the study published in the journal Biology Letters.

Seabirds are known to migrate hundreds of kilometres over open sea but it is unusual for such a small songbird to fly for so long over the ocean, DeLuca said.

Blackpoll warbler

Scientific name: Setophaga striata
Journey: The North American forest dweller migrates to the Caribbean and then to South America
Weighs: 12 grams AFP