A Review of the Impact of Mammalian Predators on Farm Songbird Population Dynamics
Prepared for SongBird Survival July 2006
by Professor Roy Brown, School of Biological and Chemical Sciences, Birkbeck, University of London
There is little doubt that some farm and song bird species have declined in recent years. Many factors are involved, including some 'modern' agricultural practices, although these have largely moderated through greater understanding and the development of agri-environmental management schemes.
Other factors, such as the problems encountered by migratory birds, have been acknowledged but the role of increased predation has not been taken as seriously as research over the last 20 years suggests it should.
There is the reality that current policies towards land use and selective species conservation have favoured the expansion of top predators at the expense of other groups.
There is much current debate about the role of raptors, such as Sparrowhawks, in the reduced success of smaller farm birds but the evidence that mammals have a major role to play has largely been overlooked, even though there is more quantified evidence for fur causing the feathers to fly rather than the feathers causing feathers to fly!
In April 2005 SongBird Survival requested Professor Roy Brown to carry out a review of the evidence, much of which is as yet unpublished, of the impact mammal predation has on farm bird populations.
The review was carried out against the background argument that increased predation, especially involving common farm active mammals, is a major if not dominant factor in the decline of farmland birds.
However unpalatable the conflict between mammal and bird activity may be to some interests it is vital that all of the real causes of songbird decline are identified so that effective remedial action may be taken.
The report was completed in 2006 and the press release and full report can be downloaded here.