Communal living can make it easier for birds to find mates, defend territory, and fend off predators. “Species can gain so many benefits from being social,” says Berberi. “Sometimes the underdog can get a boost in competitiveness based on who’s around them,” Dakin says. While the findings showed a clear pattern of dominance by solitary birds in size-matched fights, the results also offer hope for the “wimpy” birds: Having companions nearby can give social birds an edge, even when their friends stay on the sidelines. Downy Woodpeckers and Carolina Wrens, for example, are relatively small but nonetheless frequently manage to drive off competitors. Dakin calls these kinds of birds “groupy and wimpy.” On the other end of the spectrum, some more solitary birds were far more dominant than their size alone would predict. Individual birds from more social species, like goldfinches, Common Redpolls, and Black-capped Chickadees, had little success in one-on-one conflicts with birds of other species. “Those evictions aren’t random,” Dakin says, “They’re a reflection of a dominance hierarchy.” That gave them a dataset of over 55,000 “displacement interactions,” or instances when a single bird drove off another individual of a different species. “I was like ding-ding-ding, this is the one.”īerberi, Dakin, and their collaborator at Cornell, Eliot Miller, pulled the data from four recent winters of observations-Project FeederWatch runs each year between November and April-and narrowed their focus to 68 common species. “It’s incredibly rich,” Berberi says, of the FeederWatch dataset. Every showdown between junco and nuthatch or House Finch and Tufted Titmouse gets recorded, along with weather data and other details like the arrival of predator birds. Volunteers across the United States and Canada report not only the birds they see at their feeders but also the interactions between them. While he was looking for a remote-friendly project, Dakin, his adviser, told him about Project FeederWatch, a long-running community science effort coordinated by the Cornell Lab of Ornithology. Research on intangibles like social dynamics is inherently challenging, and it became harder still when the arrival of COVID-19 scuttled Berberi’s original plan to study competition between hummingbirds in the laboratory. “The behavior of animals has such an influence on how well they can survive.” “There’s a lot more to animal biology than just an individual’s measurements,” he says. student Ilias Berberi, first author of the new paper, wanted to look past physical traits. Bigger, heavier birds drive off smaller species and “win” the most squabbles. Previous studies of feeder battles established that body size matters most. Understanding the pecking order helps researchers see the bigger picture of how species interact in an ecosystem and can shed light on the evolution of different traits and behaviors. “But what we found was quite the opposite.” “My assumption was that the more social species would be more powerful for their body size,” says Roslyn Dakin, a behavioral ecologist at Carleton University in Ontario, Canada, and senior author of the study. The finding surprised the study’s authors, too. That might seem counterintuitive to an avid feeder-watcher, who knows these birds get plenty of sparring practice among their peers. It turns out, the most social birds-the ones that tend to show up in a group-are the least likely to win a face-off against an outside challenger of comparable size. Some birds stand their ground, and others flee at the first sign of conflict.īigger birds tend to be victorious in these skirmishes, but a new study published in The Proceedings of the Royal Society considered a subtler factor that affects feeder hierarchy: social life. Watch closely, and you’ll see winners and losers. With wild food sources hard to find, offerings of seed and suet can draw a crowd-and lots of tussling. Anyone with a bird feeder knows that winter can be a season of high drama.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |