February 18, 2010

Ravens Not To Blame For Decline Of Wading Birds

Ravens have been scratched out as the cause for a decline in the number of wading birds in the UK.

Raven numbers have increased in the past 20 years, but waders like lapwing and curlew have fallen by 50%.

Ravens feed on the eggs of the birds, but a new study shows that its links to the decline were irrelevant.

The RSPB and University of Aberdeen's Center for Environmental Sustainability (ACES) carried out research that suggests habitat and vegetation and foxes could be to blame.

The project was funded by government agency Scottish Natural Heritage (SNH).

The study will help SNH when considering applications to legally kill ravens to protect other species. 

Farmers say ravens prey on livestock in the Highlands, Islands and Argyll.

Farmers were allowed to shoot more of the crows than previously permitted last January in an effect to protect newborn lambs and calves. 

Dr. Arjun Amar, the leader of the study and a senior conservation scientist with RSPB, told BBC News that ravens had undergone a "welcome" recovery over the past 20 years.

The scientists write in the British Ecological Society's Journal that "While many organizations view these changes as positive, increases in raven numbers have raised legitimate concerns among other groups, because of their perceived impact on prey species, and this can lead to conflict between land managers and conservation organizations.

"We hope that this new research will help the licensing authorities balance the need to safeguard populations of vulnerable, recovering predators, whilst at the same time acknowledging and addressing concerns over increasing predator populations."

Director of ACES, Steve Redpath, said the reasons for upland wader populations suffering had yet to be clearly understood.

He said, "It is often the case that predators are assumed to be responsible, but this is not always the case.

"This research found no strong evidence to suggest that ravens were responsible for changes in wader numbers, implying that we need to look elsewhere to discover the cause for these large-scale declines."


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