Three Colorado bird researchers announced today that they have discovered the answer to a longstanding mystery about black swifts.
These birds have been the objects of focused research in Colorado for more than half a century. But no one had been able to determine where the birds migrated when they left their cliffside nests and flew south for the winter.
The Colorado trio found, using tiny geolocators in bird “backpacks,” that Black Swifts head for a rainforest in western Brazil — a 4,300-mile trip.
Jason Beason with the Rocky Mountain Bird Observatory, Caroline Gunn, a veterinarian and fish pathologist with the Colorado Division of Wildlife, and Kim Potter, a U.S. Forest Service wildlife technician, announced their surprising finding during the “Black Swift Big Reveal” at a Denver church this evening .
The researchers were surprised by the birds’ winter home because they had expected to find them in some mountainous area of South or Central America rather than in a lowlying rainforest in a country where black swifts had never been documented as a species.
The trio was finally able to crack the black swift conundrum by capturing four birds near Rifle and Ouray in 2009 and outfitting them with geolocators. The locators had been developed into tiny enough devices that they would not hinder the birds’ flight.
The team was able to recapture three of those four birds the next year to retrieve the locators. The swifts had returned to the same cave and waterfall where they had nested before migration.
The researchers then calculated longitude and latitude based on data in the geolocators that showed the length of days.
“To make a discovery like this in this day and age is amazing,” Beason said.
The findings will be published in the March issue of the Wilson Journal of Ornithology.
The trio plans to continue more research on black swifts. Their successful tracking method is expected to be used in other parts of the country to see if black swifts from other states also go to Brazil.
The black swifts are considered a “sensitive species” in Colorado by the U.S. Forest Service and a species of greatest need by the Colorado Division of Wildlife.
Black swifts are being watched because ornithologists believe they are a species that could be most affected by climate change.
Nancy Lofholm: 970-256-1957 or nlofholm@denverpost.com
