Wild bird populations are generally thought to benefit from being given additional food in winter but our understanding of the effects of such food provision is incomplete. The results of a new study, carried out by researchers at the University of Exeter and the British Trust for Ornithology (BTO), has found that feeding wild blue tits in winter resulted in less successful breeding during the following spring.
The research, just published in Scientific Reports, revealed that woodland blue tits that were provided with fat balls as a supplementary food during the winter months went on to produce chicks that were smaller, of lower body weight and which had lower survival than the chicks of birds that did not receive any additional food.
Dr Jon Blount from the University of Exeter who led the research said: “Our research questions the benefits of feeding wild birds over winter. Although the precise reasons why fed populations subsequently have reduced reproductive success are unclear, it would be valuable to assess whether birds would benefit from being fed all year round rather than only in winter. More research is needed to determine exactly what level of additional food provisioning, and at what times of year, would truly benefit wild bird populations.”
Dr Kate Plummer, lead author of the paper, said: “There could be a number of different explanations for our results. One possibility is that winter feeding may help birds in relatively poor condition to survive and breed. Because these individuals are only capable of raising a small number of chicks, they will reduce our estimation of breeding success within the population. But more research is needed to understand whether winter feeding is contributing to an overall change in the size of bird
Read more at: Phys.org