There has been some debate recently about the wisdom of feeding birds during the winter months. The supposed downside is birds becoming too dependent on human beings for sustenance.
Jeff Hoover, an avian ecologist with the Illinois Natural History Survey, said people shouldn’t stop filling their feeders.
“By and large feeding can have a positive effect on birds, particularly in hard winters,” he said. “But, there are always caveats. There may be some unintended consequences that might not be deemed positive.”
Hoover said situations can arise that cause individuals to take a break from filling their feeders. Cooper’s hawks have a tendency to prey on birds frequenting feeders. Some songbirds nest near regular feeding sites. Blue jays sometimes engage in nest predation.
“To me, that’s just part of what is going on in the environment in my back yard,” Hoover said.
Last spring there was an outbreak of avian conjunctivitis, a disease affecting the eyes. The disease is contagious, passed on by close contact. Bird enthusiasts were asked to space their feeders to avoid crowding, clean their feeders with a 10 percent bleach solution and remove build-ups of old seed and droppings.
“I don’t think they outweigh the positives that suggest people should stop doing it,” Hoover said. “There are winners and losers with everything.”
He also cited recent research which indicates birds rarely become solely dependent on feeders during the winter. Conversely, the presence of feeders might impact local populations.
“That (feeding) allows them to stay farther north than they may otherwise have stayed,” Hoover said. “Things have changed a lot in the last 100 years for a lot of different reasons. During the winter, birds get about 20 percent of their food from feeders. There are natural sources. They don’t depend exclusively on feeders.”
Although, there can be brief periods when feeders are life savers.
“Those periods of time are like a three-day cold snap,” Hoover said. “Those cold snaps or ice or snow events in the winter, they can be a big blow to birds that are in poorer conditions. They may not be able to survive those three days because they live day-to-day. They don’t have a lot of reserves to get them through long periods.
“I’m usually an advocate of not feeding birds during the summer. During the summer birds are mostly eating insects anyway.”
Feeding during the summer can increase the presence of brown-headed cowbirds, which are notorious for nest predation.
And, in the final analysis, man has already had a major impact in shaping the birds’ environment by destroying natural habitat through the construction of residential areas, agricultural practices and introduced species.
“That is a very good point and an interesting question to ponder,” Hoover said. “The hand of humans has left a very large imprint.
“We are still pretty far away from being able to understand how bird feeders affect long term populations. They are probably a minor piece of the puzzle.”