Written by Peter Pearsall/Photo of Townsend’s warbler on suet feeder by Dan Streiffert

As the pandemic forces us to spend more time inside our homes, backyard birdwatching is becoming increasingly popular. By many measures, birdwatching itself hasn’t enjoyed this sort of widespread interest in decades. Backyard bird feeders are a source of joy to many of us, and they can provide essential calories to birds during times of need. But bird feeders can also be a source of disease if not properly maintained.

Feeding wild birds is not a black-and-white issue; as with most things, there are pros and cons to consider. One of the major cons is the potential for disease transmission. In the wild, birds rarely congregate closely around food sources as they do with feeders. This crowding puts birds in close proximity with one another. When birds inevitably excrete waste in or around bird feeders, bacteria such as Salmonella can spread between individuals.

Salmonellosis, a disease transmitted by bacteria in the genus Salmonella, often afflicts bird species that visit feeders, including finches, redpolls and siskins. Infected birds may appear weak or lethargic, with swollen eyes and fluffed-up feathers.

As a rule, feeders should be disinfected twice a month, even if no signs of disease are present. If birds suspected of carrying Salmonellosis are spotted near your feeders, take them down immediately. Wash the feeders and wait for a week or so before setting them back out. The birds will thank you for it!