To feed or not to feed
Getting in touch with nature in an urbanized world can be as simple as putting a bird feeder in your backyard. However, what are the potential consequences of this act? Bird-window collisions are one of the largest threats facing urban bird populations in Canada. A new study out of the University of Alberta engages citizen scientists to determine the effects of feeders on bird-window collisions.
Despite the popularity of feeding wild birds, the effects of bird feeders and year-round feeding on birds have not been well documented, particularly in relationship to bird-window collisions. "Backyard bird feeders create an important link between humans and nature," says Justine Kummer, a graduate student at the University of Alberta and lead author of the study, the first ever to manipulate bird feeders at actual residential houses. "Improving the relationship between the general public and nature can promote biodiversity and conservation. We are working to find successful ways to reduce bird-window collisions, beneficial not only for birds but also for the millions of people who feed them."
In Canada, it is estimated that up to 42 million birds die each year from collisions with windows, with residential homes accounting for 90% of building-related mortality. Trials were conducted on 55 windows at 43 residences in Edmonton and the surrounding area. Homeowners were asked to search their study window daily for evidence of bird-window collisions. Though there were 94 reported collisions with the presence of a bird feeder, there were also 51 collisions in cases when no feeder was present, meaning there is no black and white answer. Twenty-six of the windows never experienced a collision during the study, showing that some houses are more at risk than others, regardless of the presence of the feeder.
"We've determined that the presence of a bird feeder does indicate collision risk, but there are other factors involved," says Kummer. She notes that vegetation and house characteristics can also influence whether a residence is likely to have a large number of collisions. "The general public enjoys feeding birds in their yard, but they want to know how to do so safely. Homeowners can certainly reduce some window collision risk by altering feeder placement."
The study builds on previous work at the University of Alberta, well known for its conservation and biodiversity efforts. The paper was co-authored by Kummer's graduate supervisor Erin Bayne, associate professor in biological sciences at the University of Alberta. Bayne's research team focuses on understanding the cumulative ecological impacts of human activities on biodiversity.
The findings, "Bird feeders and their effects on bird-window collisions at residential houses," were published this fall in the journal Avian Conservation and Ecology.