Buzzards less likely than humans to kill pheasants, study findsFebruary 26th, 2013 by Harriet Jarlett in Biology / Plants & Animals
Scientists have shown that pheasants are more likely to be killed by people than by birds of prey.
The study, by researchers in the UK and Brazil, found that buzzards are just a minor cause of pheasant deaths. It also warned that persecuting them could lead to fewer rather than more pheasants.
The new report was commissioned in response to a call from DEFRA for more research into whether controlling the Common Buzzard could raise pheasant numbers. The call came after they withdrew a controversial proposal suggesting using sub-lethal measures to raise pheasant numbers. DEFRA asked for more research into the topic so any revised proposals would be based on scientific evidence.
The government's original proposal suggested controlling buzzards through sub-lethal methods like destroying empty nests or by providing alternative prey.
Professor Ian Newton from the Centre for Ecology & Hydrology, co-author of the paper, explains, 'the idea behind the government's proposal was that by giving buzzards some easily-available alternative food source like rabbit carcasses, there will be less incentive for them to attack pheasants.'
But the research, published in Conservation Letters, showed that only one to four per cent of pheasant deaths are ultimately caused by buzzards.
'The factors killing pheasants are many and varied. People - either directly by shooting or indirectly by running them over - and foxes top the list though,' says Dr Alexander Lees from the Museu Paraense Emílio Goeldi in Brazil, lead author on the study.
Between 20 and 35 million pheasants are released into the UK countryside each year by the shooting industry, but only half reach maturity. Gamekeepers thought many of the chicks were eaten by birds of prey, costing the industry money and prompting wildlife minister Richard Benyon to propose this solution.
The study raised the point that by making buzzards a scapegoat and ignoring other predators that eat pheasants it could exacerbate losses instead. Buzzards don't just eat pheasants; they also prey on their other predators. With fewer buzzards there would be less control on these other predators and they would grow in numbers, possibly killing more pheasants than the buzzards might have done. These complex predator/prey relationships must be considered when trying to raise the numbers of one species.
Commenting on the withdrawal of the proposed measures last year, Benyon says, 'it is right that we make decisions on the basis of sound evidence and we do need to understand better the whole relationship between raptors, game birds and other livestock. I will collaborate with all the organisations that have an interest in this issue and will bring forward new proposals.'
A revised proposal is now expected to be published. Dr Lees concludes, 'we anticipate a new proposal and hope it considers our commentary and focuses on making predation more difficult.'
More information: Lees, A. C., Newton, I. and Balmford, A. (2013), Pheasants, buzzards, and trophic cascades. Conservation Letters doi: 10.1111/j.1755-263X.2012.00301.x
Source: PlanetEarth Online
This story is republished courtesy of Planet Earth online, a free, companion website to the award-winning magazine Planet Earth published and funded by the Natural Environment Research Council (NERC).
"Buzzards less likely than humans to kill pheasants, study finds." February 26th, 2013. http://phys.org/news/2013-02-buzzards-humans-pheasants.html