Status of the Nightingale Luscinia megarhynchos in Britain at the end of the 20th Century with particular reference to climate change

Capsule The population level may be unchanged but the range has contracted. Aims To establish the current status of the Nightingale in Britain and explore causes for any changes. Methods Over 3000 sites where Nightingales were known to have occurred since 1980 were surveyed by volunteers between mid-April and early June 1999. A selection of 135 random tetrads were also surveyed to gauge the efficiency of the volunteer survey in locating Nightingales. Results The survey located 4565 singing male Nightingales while the random tetrad surveys suggest that c. 32% of birds occur away from known sites, increasing the estimate for the British Nightingale population to 6700 males (95% confidence limits 5600-9350) in 1999. A higher proportion of Nightingales was found in scrub (46.7%) than in 1976 (28.4%), suggesting a recent shift in habitat use. Conclusion There is little evidence of a change in the size of the British Nightingale population, probably because earlier surveys underestimated numbers. The range has contracted markedly over the last few decades and numbers outside the core areas in southeast England are now low. Changes in habitat quality and. increasing deer populations have caused decreases on a local scale. Changes in climate on the breeding grounds and general changes in climate or habitat suitability on the African winter quarters are likely to be important in influencing the distribution within England. Models of the effects of future climate change on Nightingale distribution in Britain predict that numbers and range should increase over the next few decades.