How does your bird seed grow? With noxious weeds from invasive seeds, scattered wherever birds go? You bet. A few years ago, researchers identified the seeds of more than 50 weed species in commercial wild bird feeds, according to Organic Gardening. “It’s easy enough to snuff out noxious weeds that sprout under the feeder,” the magazine reports. “But when birds eat the seeds and the fly off and distribute weeds in their droppings, wild areas can be affected.”
Over half the weed seeds researchers found were viable; 10 of them were noxious—aggressive spreaders that can be harmful to other plants, animals, and humans. “When we informally questioned landowners and farmers to investigate the spread of a relatively new weed in the Pacific Northwest—velvetleaf—we found it growing in the soil beneath backyard birdfeeders,” horticulturist Jed Colquhoun, one of the researchers, recently told SeedWorld, an agriculture and seed industry publication.
What to do? Organic Gardening suggests choosing feeds that won’t sprout, including peanuts, sunflower hearts, and suet cakes, or growing a “bird buffet”—a garden of native perennials and grasses upon which birds can feast. Or make your own bird feed blends or homemade suet cakes with recipes from Mother Earth News. If you do buy commercial feed, Christian Science Monitor recommends making sure that it is baked so weed seeds are not viable.