Do Feeders Create Dependency?
All of us who feed birds ask ourselves if we are putting them at risk if we are no longer able to maintain the feeders in the winter when food is scarce. This study from the University of Wisconsin by Margaret Clark Brittingham, Ph.D, goes a long way towards answering that question.
It was conducted over a three-year period in the 1980s by banding hundreds of chickadees from two similar habitats. Chickadees are one of the smallest birds to winter over. Their small body size and high metabolic rate create an intense need for energy, so they must spend much of the daylight hours foraging for food. They were the perfect subject for this study. One site for the study had been provided with bird feeders stocked with sunflower seeds for over 25 consecutive years. The habitat of the second site was similar to that of the first site except that it had never had bird feeders.
To start the study, two winters were spent comparing survival rates of chickadees with feeders to those without. On the third year, the Brittingham team removed the feeders from the study site. The object was to compare the survival rate of the potentially feeder-dependent chickadees to those who did not have feeders. The two sites were more than a mile apart, farther than chickadees usually travel in search of food. Both groups experienced the same weather, with temperatures in two months averaging below zero.
In terms of survival rates, which were about 85% overall, there was practically no difference between the two study sites. Birds that had used bird feeders in the past were no less able to survive on a natural food supply, even though feeders were constantly available for the preceding 25 years.
The researchers who had done the preliminary study over the two winters when the bird feeders were still in place were not surprised by these results. They had found that despite the presence of feeders, the resident chickadees still obtained some 79% of their daily rations from natural resources. Chickadees are truly opportunistic. In winter, they will search out insect eggs and larvae, mites and other arthropods, seeds, carcass remains and all sorts of other available energy sources.
Conclusion: "Feeders can be an important wildlife management tool for maintaining population of feeder users in suburban areas. In addition, feeders increase positive human-wildlife interactions. Although chickadees depend primarily on natural food sources, feeders provide an important supplement to their natural diet." Enjoy wild bird feeding for the pleasure it brings, the sights, sounds and antics. Wild birds are our guests, not our pets.
Next month, we will address the issue of black bears and bird feeders. The last two years, the Fish & Wildlife Agencies have instituted a new directive regarding roaming wild bears. We like to call it the "do nothing policy." We will give you the facts about birds and bears. Loss of habitat, diminishing bear numbers, human encroachment and housing development are not the culprits. The real reasons for increased bear encounters will shock you. Don't miss the next issue!