In May 2020, as the first wave of the COVID-19 pandemic swept Texas, I went to an Austin nature store and bought several bird feeders. Various birds, drawn by seed and other food, came soon afterward. I wasn't alone. Feeders have long been a popular way to connect with nature and draw in native or nonnative species. But over the past two years, bird feeding has suddenly increased in popularity.
The benefits of all of this supplying have tended to go unquestioned. After all, habitat destruction from human activity is a leading cause of bird population declines, so feeding birds seems like an obvious way to help make up for that loss. But a recent review paper raises a troubling possibility: bird feeding could be reshaping some local environments. "If you're throwing millions of tons of additional nonnatural resources into an environment, you're going to get massive, massive impacts," says lead study author Jack Shutt, a conservation ecologist at Manchester Metropolitan University in England. "And they're not always going to be the ones that you're expecting."
Bird feeding carries a few well-recognized risks. The first among them is disease spread. In 2005 scientists concluded that shared feeders in the U.K. may have helped dove trichomoniasis(滴虫病) jump into European Greenfinches, as a result, it killed up to half a million birds. In the U.S., trichomoniasis outbreaks connected with dirty feeders are common bird killers. "You've got different species pecking(啄食) at the same bit of plastic, which is covered in various bird bodily liquid," says study co-author Alexander Lees, an bird expert at Manchester Metropolitan University. "It's a cause of disaster."
What's necessary, Lees says, is taking the potential impacts seriously enough to carry out further study, which would allow experts to make much more recommendations about where to feed and where to avoid it. Such studies could also help researchers make targeted recommendations about what sorts of food to offer.
