Publication Type: | Journal Article |
Year of Publication: | 2006 |
Authors: | Langston, RHW, Smith, T, Brown, AF, Gregory, RD |
Journal: | Bird Study |
Volume: | 53 |
Date Published: | 2006 |
ISBN Number: | 0006-3657 |
Keywords: | Acanthis flavirostris, Carduelis, Carduelis flavirostris, Fringillidae, Ireland, Linaria, Linaria flavirostris |
Abstract: | Aims To provide a baseline population estimate of breeding Twite in the UK. Methods In Scotland and England, three visits were made in May to July to a stratified random sample of 1-km squares, walking modified point transects, at 200-m intervals. Whilst recording was continuous, at 100-m intervals within suitable breeding habitat, observers made five-minute stops to scan and listen for Twite. Habitat cover was recorded to the nearest 10%. Supplementary records were collated from Wales and Northern Ireland. Several methods were used to produce population estimates, with bootstrapped confidence intervals. Results There were an estimated 10 000 pairs of breeding Twite in the UK in 1999, with the range lying between 6000 and 15 000 pairs. The majority, 9948 (95% confidence intervals 6293?14 586) pairs, was recorded in Scotland and England. Conclusions The population estimate provides a baseline for future surveys, although similar surveys are required in Wales and Northern Ireland (or all of Ireland) for completeness. A three-visit protocol is suggested for future surveys. There is accumulating evidence for the continued decline of Twite breeding range and numbers in the UK.Aims To provide a baseline population estimate of breeding Twite in the UK. Methods In Scotland and England, three visits were made in May to July to a stratified random sample of 1-km squares, walking modified point transects, at 200-m intervals. Whilst recording was continuous, at 100-m intervals within suitable breeding habitat, observers made five-minute stops to scan and listen for Twite. Habitat cover was recorded to the nearest 10%. Supplementary records were collated from Wales and Northern Ireland. Several methods were used to produce population estimates, with bootstrapped confidence intervals. Results There were an estimated 10 000 pairs of breeding Twite in the UK in 1999, with the range lying between 6000 and 15 000 pairs. The majority, 9948 (95% confidence intervals 6293?14 586) pairs, was recorded in Scotland and England. Conclusions The population estimate provides a baseline for future surveys, although similar surveys are required in Wales and Northern Ireland (or all of Ireland) for completeness. A three-visit protocol is suggested for future surveys. There is accumulating evidence for the continued decline of Twite breeding range and numbers in the UK. |
URL: | http://www.tandfonline.com/doi/abs/10.1080/00063650609461416 |
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