Temporal variation in the biometrics of Turtle Doves Streptopelia turtur caught in Britain between 1956 and 2000.
We analysed biometric data collected from 589 Turtle Doves Streptopelia turtur measured between 1956 and 2000 in Britain. Male wing length was on average 4 mm longer than females, which were on average 8 mm longer than juveniles. Wing length increased by approximately 5 mm over the period 1956 to 2000, probably owing to differences in measuring techniques over the years. Males were heavier than females by about 5 g, and females were in turn 10 g heavier than juveniles. Turtle Dove body weight varied with season, with birds being heavier by about 10 g in autumn. Using the ratio of wing length to body weight to represent body condition, we found no annual variation in body condition, but body condition was lowest in spring and highest in autumn. Because we were unable to detect a change in average body condition over time, the hypothesis that lowered body condition caused reduced breeding productivity in the 1990s is unsubstantiated.