Status of breeding Twite Carduelis flavirostris in the UK

Abstract

Capsule: The first comprehensive estimate of breeding Twite in the UK indicates that there were approximately 10 000 pairs in 1999. 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. © 2006 British Trust for Ornithology.