Now that the myth has been proven true, biologists are calling the journey of the blackpoll warbler “one of the most extraordinary migratory feats on the planet."
For decades birding enthusiasts and scientists alike have wondered if in fact the wee boreal forest songbird known as the blackpoll warbler could really migrate from their Northeastern homes in a straight line, over the Atlantic Ocean, without stopping, all the way to the warmer climes of South America. It was a mystery of mythic proportions – we’re talking 1,410 to 1,721 miles (2,270 to 2,770 km) in just two or three days. It was the stuff of avian apocrypha.
But now for the first time, an international team of biologists report "irrefutable evidence" that indeed these tiny superheroes make the journey, nonstop – landing somewhere in Puerto Rico, Cuba and the Greater Antilles – before flying on to northern Venezuela and Columbia. Imagine, 1,410 to 1,721 miles, without stopping. It’s an accomplishment lauded by all.While birds like gulls and albatrosses are known to be swift trans-oceanic fliers, the blackpoll warbler is a crooning forest dweller – most songbirds that head to South America do so by way of land as a water landing would prove fatal.
Study author Bill DeLuca from the University of Massachusetts Amherst says, "For small songbirds, we are only just now beginning to understand the migratory routes that connect temperate breeding grounds to tropical wintering areas. 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."
The researchers made their discovery by means of miniaturized geolocators attached to the birds’ backs. While the teeny warblers only weigh in at around half an ounce, traditional tracking devices have proven to burdensome. But advances in technology have led to petite geolocators weighing a mere half a gram, allowing new data where once scientists had only ground observations and radar to rely on.
To ramp up for their journey, the warblers pack on the pounds (well, grams), explains Ryan Norris of the University of Guelph. "They eat as much as possible, in some cases doubling their body mass in fat so they can fly without needing food or water. For blackpolls, they don't have the option of failing or coming up a bit short. It's a fly-or-die journey that requires so much energy."
Chris Rimmer from the Vermont Center for Ecostudies says, "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."
And while it may seem meddlesome to be strapping equipment to the backs of the teeny things in the first place, DeLuca makes a good point: “Many migratory songbirds, blackpolls included, are experiencing alarming population declines for a variety of reasons, if we can learn more about where these birds spend their time, particularly during the nonbreeding season, we can begin to examine and address what might be causing the declines."