In our last article, we described how an extensive 4 year wild bird feeding study by Professor Margaret Brittingham from the University of Wisconsin was conducted from 1984-1988. This study was set up to track the survival rate of two distinct, controlled groups of chickadees during two straight winters. One banded group had sunflower seed feeders removed after 20 years of existence. The other banded group of birds, verified outside the accepted range of the feeder group, had never received their food sources through human contact.The winters were average in terms of temperature, snow cover and wind conditions. In terms of survival rates, which were about 85%, the exhaustive study concluded that there was no marked difference between the two groups of chickadees. The other 15% were presumed to have perished, since chickadees remain in the same area throughout a winter.
Birds that had used feeders in the past were no less able to survive on a natural food supply, even though feeders were constantly available for the preceding 20 years. This is not surprising.
During the preceding two winters, at the site where there were sunflower seed feeders, the banded chickadees were tracked as they obtained some 79% of their daily rations from natural food sources.
Chickadees are truly opportunistic. In winter, they will search out insect eggs and larvae, mites and other anthropods, seeds, carcass remains and all sorts of available energy sources.
Both the controlled and experimental sites were in relatively undisturbed rural locations in Wisconsin composed primarily of deciduous woods. The study did not see what the effect would be if the feeders were suddenly removed or left empty right in the middle of winter. However, birds are used to food sources disappearing in winter, due to snow, ice or foraging by other birds.
There is one interesting note about the study. It was determined that during abnormally severe weather conditions, five days or more of temperatures below 18° F, there was a marked difference in survival of the controlled group of chickadees. Birds with access to feeders maintained higher weights and were able to replace depleted energy reserves with minimal foraging. During periods of extreme cold, the ability to get a large amount of energy in a short period of time with minimum effort may be critical to the survival of the weak and older chickadees. Logically, this holds true for humans as well.
People who feed birds can indeed help extend the range and survival rates of wild birds during times when natural food sources are scarce. However, when nature provides an abundance of food, your backyard is just considered one more food sources, never the primary food sources.
Our advice for almost two decades of service to our customers is to enjoy this hobby for what it offers. Peace, tranquility and the joy of sitting back and watching nature right outside your window. Have fun with your backyard birds.
Wild Bird Depot is located on Rt 11 in Gilford, NH. Steve White is a contributing author in major publications, a guest lecturer at major conventions in Atlanta and St. Louis as well as the host of WEZS 1350AM radio show “Bird Calls” with Lakes Region Newsday @ 8:30AM. Wild Bird Depot has donated over $5,000 to local rehabilitators and local nature centers since 1996. Be sure to check out our blog “Bird Droppings” via our website www.wildbirddepot.com. Like us on Facebook for great contests and prizes.