Feeding wild birds through the winter might make you feel like a good interspecies neighbor, but it turns out that your apparent good deed may be doing more harm than good.
A recent study by the British Trust for Ornithology found that feeding wild birds in winter may have a detrimental effect on their reproduction come spring.
Over the three-year study, birds provided with extra food in the winter consistently hatched smaller chicks the following spring—and the same group’s fledglings had a 10 percent lower rate of survival than a flock that had been left to fend for itself.
According to study coauthor Kate Plummer of the University of Exeter’s Centre for Ecology and Conservation, it may be that winter feedings “encourage birds to breed in areas of low natural food”—which then can’t support growing chicks when spring rolls around. Another theory: “Winter feeding may actually enable poor-quality birds to survive the winter,” she says, resulting in poorer breeding success the following year.
Not willing to give up your feeder? Researchers say the downsides of wintertime feeding can probably be balanced by providing healthy food for wild birds year-round.