For over 50 years, clues have suggested that the tiny forest-dwelling songbird blackpoll warbler heads to South America from eastern Canada and New England each fall to migrate by flying over the Atlantic Ocean. Researchers finally have proof of this feat, reporting in the journal Biology Letters about the songbird's non-stop trans-Atlantic flight.
For the first time, researchers have irrefutable evidence showing blackpoll warblers go on to fly non-stop between 1,410 and 1,721 miles in two to three days, making a stop in the Greater Antilles, Cuba and Puerto Rico before continuing to Colombia and northern Venezuela.
To track the bird's flight, researchers used solar or light-level geolocators fitted on several blackpoll warblers like tiny backpacks. Before, researchers only had radars and ground observations to go on.
Bill DeLuca from the University of Massachusetts Amherst explained that researchers are only just now starting to understand the migratory routes small songbirds take, so scientists were excited to find out that the blackpoll warbler's flight path is the longest recorded over water for its kind.
While this is not the first time for birds to travel over oceans, it's a remarkable discovery because the blackpoll warblers are forest dwellers. Most songbirds also migrate to South America for winter using a less risky route, cutting south through Central America and Mexico.
Researchers are still not sure why the blackpoll warbler would choose a more perilous journey over safer coastal routes, but they posit that it might be because migration is the most difficult task a bird has to undergo. As such, the blackpoll warbler simply wants to get it done as quickly as possible, taking the risk flying over the Atlantic Ocean to get to its destination sooner.
The light-level geolocators strapped on several blackpoll warblers work by measuring day lengths at latitudes and solar noon times at longitudes. The instrument records daylight measurements on various locations, allowing researchers to plot out the bird's flight path. According to geolocators retrieved by the researchers, the blackpoll warbler does indeed fly over the Atlantic directly.
To make sure they are ready for the long flight, blackpoll warblers fatten up, sometimes even doubling their body mass in fat. This ensures they will have everything they need without stopping for food or water.
Researchers from the University of Guelph, Vermont Center for Ecostudies, University of Exeter, UK, Bird Studies Canada, Acadia University, and Smithsonian Conservation Biology Institute also participated in the study.
Photo: Andy Reago/Chrissy McClarren | Flickr