Feeding wild birds on bread and seed encourages high densities of introduced bird species at the expense of native species, thereby altering urban bird communities, according to a new study
Tuesday 5 May 2015 08.32 BSTLast modified on Tuesday 5 May 201516.44 BST
Feeding wild birds is a hugely popular pastime worldwide. But this is essentially a massive global supplementary feeding experiment with ecological effects that are poorly understood. A newly-published study of bird feeding in New Zealand reports that the common practice of feeding bread and seed alters the species composition observed in urban bird communities such that introduced bird species were the big winners at the expense of native birds. The study suggests that supplementary feeding of bread and seed encourages higher densities of introduced bird species, which may in turn, decrease local populations of native bird species.
Bird feeding is certainly one of the most universally popular hobbies in the world. For example, according to a 2006 US Fish and Wildlife Report: “Over 55 million Americans over the age of 16 feed wild birds and spend more than $3 billion a year on bird food, and $800 million a year on bird feeders, bird baths, bird houses and other bird feeding accessories.” In a 2002 report, the Department of the Environment, Food and Rural Affairs(DEFRA) estimated that more than 60 percent of UK households with a garden feed wild birds, and a British Trust for Ornithology (BTO) study analysed data collected during the winter of 2002-2003 by the Garden Bird Feeding Survey, a citizen science project, and reports that 60,000 tonnes of food are presented annually to birds (Glue, 2006).