Bird Feeding - Impact

Impact

A study conducted in Sheffield, England, found that the abundance of garden birds increased with levels of bird feeding. This effect was only apparent in those species that regularly take supplementary food, raising the possibility that bird feeding was having a direct effect on bird abundance. In contrast, the density of feeding stations had no effect on the number of different bird species present in a neighbourhood.

The use of bird feeders has been claimed to cause environmental problems; some of these were highlighted in a front-page article in The Wall Street Journal.

Prior to the publication of the Wall Street Journal article, Canadian ornithologist Jason Rogers also wrote about the environmental problems associated with the use of bird feeders in the journal Alberta Naturalist. In this article, Rogers explains how the practice of feeding wild birds is inherently fraught with negative impacts and risks such as fostering dependency, altering natural distribution, density and migration patterns, interfering with ecological processes, causing malnutrition, facilitating the spread of disease and increasing the risk of death from cats, pesticides, hitting windows and other causes.

In a paper in the journal Oecologia, it was reported that feeding of blue tits and great tits with peanut cake over a long time period significantly reduced brood size. This was driven by smaller clutch sizes in both species and lower hatching success rates for blue tits. Studies by the University of Freiburg and Environment Canada found that Blackcaps migrating to Great Britain from Germany had become adapted to eating food supplied by humans. In contrast blackcaps migrating to Spain had bills adapted to feeding on fruit such as olives.

It's essential that you regularly clean, rinse and dry your bird feeding stations. This is especially important, because unclean bird feeders may contribute to the spread of salmonella, as well as viruses, amongst the wild bird population. It also important that bird food is kept dry, and is not allowed to go mouldy, as rotten food has the potential to poison wild birds.