The Hawk and Owl Trust has joined with the British Trust for Ornithology (BTO) to continue the long-established Hen Harrier Winter Roost Survey which the Trust has helped fund for some years.
The 2007/08 season was the survey's 25th year, making it probably the longest running, non-breeding survey of a single bird species in the world. Volunteers record hen harriers on specific days each winter when the birds have moved from their upland breeding areas to low-lying ground throughout Britain. Hen harriers roost communally, with up to 90 birds at a single site.
Information collected over the years is of key nature conservation importance and it was vital that the work continued, which is why the Trust has joined with the BTO, the experts on bird surveying and data analysis.
Pellet analysis
By analysing pellets from these roosts, Roger Clarke not only improved our understanding of the diet of these raptors in winter but was also able to investigate the diet of their farmland bird prey. This information has helped to explain the recent decline in farmland birds, as it has shown that annual arable weeds are vital for the winter survival of many of these species.
This evidence can be used in the design of agri-environment schemes and also emphasises the potential dangers of herbicide-tolerant GM crops to our bird life.
The survey was started by the late artist and author Donald Watson and Hawk and Owl Trust accountant and scientific adviser Dr Roger Clarke, who co-ordinated it until his death at the beginning of 2007.
