Washington, Apr 4 : Feeding birds in your backyards each year, often out of a desire to help the animals, may not always have positive outcomes for the birds, according to a new study.
According to the meta-analysis led by Gillian Robb from Queen's University Belfast, UK and by Stuart Bearhop from University of Exeter, UK, bird feeding can compel birds to make poor decisions later in life.
Bird feeders persuade birds to settle in an area that cannot support them once supplemental feeding is stopped. These feeders create a population level that could not be sustained by natural levels of food.
There are also times when feeding can affect the timing of a bird's life in unexpected ways, the authors said.
One study, for example, showed that Florida scrub jays breeding in suburban habitats with access to supplementary food breed earlier, but find themselves out of sync with natural food items which are important when rearing nestlings. This means the extra food can lead to a decrease in breeding success rather than an increase.
However, during the analysis, researchers also found that feeding did not increase the birds' risk of predation, and also lowered the predation levels by domestic cats.
"Changing the natural dynamics of food supply at such a large scale represents a major intervention in the ecology of birds," said Robb.
"But we have a remarkably limited understanding of the impacts of bird feeding," he added.
The review is published online in Frontiers in Ecology and the Environment.