Tiny Blackpoll Warbler migrates thousands of miles non-stop

The 12 gram (0.42 oz) Blackpoll Warbler travels from the northeast of North America, flying non-stop for three days during its trip to South America, researchers reported after carrying out an extensive study.

The tiny songbird, just slightly bigger than the British wren (Eurasian wren), flies across the ocean covering from 2270 to 2770 kilometres (1,410 to 1,721 miles) without stopping for food or rest.

One of the study researchers described the little bird’s feat as “on the brink of impossibility”.

First author Bill DeLuca, an environmental conservation research fellow at the University of Massachusetts Amherst, said:

“For small songbirds, we are only just now beginning to understand the migratory routes that connect temperate breeding grounds to tropical wintering areas.”

Blackpoll Warbler with tracker

A Blackpoll Warbler with a miniaturized light-level geolocator on its back. (Image: Vermont Center for Ecostudies)

“We’re really excited to report that this is one of the longest nonstop overwater flights 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.”


They accumulate fat before taking off

Before their ultra-marathon fly-or-die flight (over the ocean), the birds build up their fat stores, eventually doubling their body mass in fat so that they can fly non-stop without needing to stop for food or water.

In this latest study, published in the academic jounal Biology Letters (citation below), the authors explain that several fundamental aspects of migration remain a mystery, mainly because of our inability to follow small animals over great distances.

For over fifty years, biologists had hypothesized that the Blackpoll Warbler (Setophaga striata) departed in the autumn from the north east of North America and flew non-stop over the Atlantic Ocean to either the northeastern coast of South America or the Greater Antilles in the Caribbean Sea.

Blackpoll Warbler

The Blackpoll Warbler is a small bird, weighing about the same as a ball point pen. (Image: Wikimedia)

Blackpoll Warbler joins its larger cousins as a super migrator

We know that larger birds, such as sandpipers, albatrosses and gulls fly enormous distances across the ocean. A team of researchers from the US, Canada and UK attached tiny tracking devices to 40 Black Warblers – 20 in Nova Scotia and 20 in Vermont – as part of the study and monitored their movements. They wanted to determine whether this tiny forest dweller did what most of its peers dare not do.

The researchers said the bird flew from the northeast of North America, stopped at the islands of Puerto Rico and Hispaniola to rest and feed, and then crossed the Caribbean Sea towards wintering destinations either in Venezuela or northern Columbia.

In an Abstract in the journal, the authors wrote:

“The Blackpoll Warbler, a 12 g boreal forest songbird, completes an autumn transoceanic migration ranging from 2270 to 2770 km (mean ± s.d.: 2540 ± 257) and requiring up to 3 days (62 h ± 10) of non-stop flight.”

“This is one of the longest non-stop overwater flights recorded for a songbird and confirms what has long been believed to be one of the most extraordinary migratory feats on the planet.”

Science Codex quoted Chris Rimmer, an ornithologist at the Vermont Center for Ecostudies, who said:

“We’ve only sampled this tiny part of their breeding range. We don’t know what birds from Alaska do, for example. This may be one of the most abundant warblers in North America, but little is known about its distribution or ecology on the wintering grounds in Venezuela and the Amazon.”

“However, there is no longer any doubt that the blackpoll undertakes one of the most audacious migrations of any bird on earth.”

Citation: Transoceanic migration by a 12 g songbird,” William V. DeLuca, Bradley K. Woodworth, Christopher C. Rimmer, Peter P. Marra, Philip D. Taylor, Kent P. McFarland, Stuart A. Mackenzie and D. Ryan Norris. Biology Letter. Published 1 April, 2015. DOI: 10.1098/rsbl.2014.1045.