Oct. 29, 2021 -- If you think you see a vulture when you’re out trick-or-treating, it might not be your imagination. Vultures often choose roadside locations over more isolated natural habitats when they settle down to rest for the night, according to a GPS analysis of their movements published in Scientific Reports.
This uncommon choice of resting spot may explain why U.S. black vulture and turkey vulture populations have surged in the past half century or so, when many other bird species have declined dramatically with encroaching suburban sprawl. Vultures, as unattractive as they might be, are important to ecosystems, and to us, because they eat dead things, recycling nutrients and tamping down disease. In other words, suburban streets may be serving up a smorgasbord.
Scientists have long suspected that these animals might adapt better to human-made landscapes than other birds. To see whether vultures really do thrive in habitats reshaped by human activity, a team of researchers from the U.S. Department of Agriculture examined almost 8,000 nights of GPS satellite tracking data for 11 black vultures and seven turkey vultures along the coast of South Carolina.
Most often, they found, the birds roosted near streets. They tended to reject busy city byways or dusty backroads and instead preferred a middle road, like the streets that typically run through suburban areas, surrounded by a mix of natural landscapes and human-made structures.
Although the study wasn’t designed to determine why vultures might prefer roadside resting spots, scientists suspect that these locations give them a boost when these large birds need to get moving. The warmer surface of asphalt and concrete may create thermal currents that lift them.
Easy access to food may be another roadside attraction for vultures, as roadkill makes for a good meal, the researchers note.