It’s long been hypothesized that songbirds might become dependent on bird feeders, causing an overall negative impact on their survival and well being. But now, a new study from Oregon State University suggests that this may not be the case.
“There’s still much we don’t know about how intentional feeding might induce changes in wild bird populations, but our study suggests that putting out food for small birds in winter will not lead to an increased dependence on human-provided food,” said study co-author Jim Rivers.
“The extensive and widespread nature of people intentionally feeding wildlife can have unintended consequences for free-ranging animal populations, and those consequences are best documented in birds.”Birds may not become dependent on bird feeders.
“On the negative side, it can facilitate disease transmission, restructure local communities and alter migration behavior, for example. There’s even evidence that it can lead to changes to birds’ bill structure. On the other hand, it can also have positive effects, such as enhanced body condition, wintertime survival and reproductive output.”
The OSU scientists used Black Capped Chickadees in the study, fitting them with radio frequency ID tags. Some of the birds had their flight feathers cut – either heavily cut or lightly – and a control group of birds had no feathers cut.
The chickadees are a common feeder bird and were used in a previous study on feeder habits. They also have high energy requirements and typically eat only one seed per feeder visit, so they were a perfect model organism for the study.
The intentional maiming of the birds was to increase the energy needed for flight for some individuals. The researchers looked at how often each group of birds visited the feeders to determine if those with higher energy needs visited the feeders more often.
What the scientists discovered is that the birds with trimmed feathers didn’t visit the feeders more to make up for losses in energy. In fact, the birds actually visited the feeders less for a few weeks, possibly to avoid exposure to predators until their wings healed up.
“Feather-clipped chickadees reducing their use of feeders relative to control birds suggests that foods in the environment – like seeds, berries and small invertebrates – were sufficiently available to compensate for increased flight costs and allowed them to cut back on feeder use,” said Rivers.
“It’s clear that the chickadees in our study did not increase their visitation rates nor did they increase their reliance on supplemental feed during a period when they might have benefited from it the most.”
A limitation of the study, which is published in the June 28 issue of the Journal of Avian Biology, is that it uses only one species as an example. There is still much we don’t know about feeding wildlife, even birds that are fed by millions all over the world.