Squirrels and feral cats are the major threats to songbirds.

THE GREY SQUIRREL is having a devastating impact on our songbird population. It ranks alongside the domestic and feral cat as the top predator of farmland birds. This is just one of the findings of Professor Roy Brown of Birkbeck, University of London, in a new review carried out for the wildlife charity SongBird Survival.

‘Many factors have been blamed for the decline in our songbirds in recent years. The debate about raptors has raised the issue of predation but mammal predation had largely been overlooked,’ says Professor Brown. The review shows that the true impact of this predation is much worse than expected. Professor Roy Brown’s report reveals that in areas of high squirrel density over 93% of small bird nests are predated. When this is combined with sparrowhawk activity it can result in 100% breeding failure and a loss of 85% of adult birds. He says ‘I am not blaming the lazy, often overfed domestic cat so much as the deadly feral variety. Both cats and grey squirrels are very widespread and range over habitats from treetops to ground level.’

 

The Professor assessed the effects of ten common mammals on the populations of 15 farmland bird species. He investigated predation on adult birds, on nesting/fledgling success and disturbance caused by intense predator activity. The study clearly shows that cats and grey squirrels predate severely on virtually all the songbirds in the study and increasing densities of these mammals can cause the complete cessation of breeding in many species. He also finds for example that increasing rat populations impact a wide variety of species and uncontrolled numbers of stoats can wipe out local populations of Skylarks.

The review is based on a large amount of data from multiple theme studies and single area assessments, much of it as yet unpublished, covering 115 farms and other areas in England, Scotland and Wales over set periods ranging from three to thirty two years. Professor Brown found that mammals account for between one third and three quarters of all predation losses of songbirds.

SONGBIRD SURVIVAL is a UK registered charity which aims to draw attention to the plight of our songbirds, to fund research into their decline and where necessary to press for changes in the law.

The full review can be downloaded from the website:
www.songbird-survival.co.uk