Crossbills, Distribution survey in Great Britain, 1995-2005

Royal Society for the Protection of Birds

Description

This dataset represents records collected between 1995 and 2005 as part of a wider study, which was then used to infer the breeding range of the Scottish Crossbill. The data were mostly collected between January and April in the years 1995-2005 when Crossbills can reasonably be assumed to be in a territory or breeding, however since the birds were only identified by calls breeding status can not be confirmed. The Scottish Crossbill was once thought to be a subspecies of either the Common Crossbill or the Parrot Crossbill but is now thought to be Britain's only endemic bird species. A full survey was also carried out in 2008. This survey was funded by the RSPB.

Geographic Description

All the 10 km squares north of 56 degrees and 50 minutes north, containing more than 20% woodland, were surveyed. This dataset includes some additional data collected in Wales and Eastern England which were not used in the published paper

Data quality

These data have been gathered by trained field-workers and the data are of a high quality. These data have been mapped and checked for sensitivities and typographical/geographical errors

Methods

The study was carried out from 1995-2005 during January and April when it can be reasonably assumed Crossbills are either in a territory or breeding. All 10 km squares north of 56 degrees and 50 minutes north, containing more than 20% woodland, were surveyed. In general, the larger woods were searched until at least 1 crossbill had been recorded. Multiple recordings from the same 10KM grid square were restricted to a few squares. Crossbills were lured using a characteristic excitement call broadcast from mini speakers. Lured birds are usually vocal and both flight and excitement calls can be tape recorded using a directional microphone. Sonograms were made from the tape recordings allowing species identification.

Citation

Data reproduced with the permission of RSPB

Rights

CC-BY

Digitised records