Temporal variation in the biometrics of Turtle DovesStreptopelia turturcaught in Britain between 1956 and 2000

Abstract

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.

Breeding ecology of Turtle DovesStreptopelia turturin Britain during the period 1941–2000: an analysis of BTO nest record cards

“…When investigating temporal trends and to overcome the problem of small sample sizes, particularly in the early and late years, data were grouped into five-year periods, from 1941-45 through to 1996-2000 (Table 1). In order to investigate breeding success amongst periods with different rates of population change we defined three phases in the population trend of British Turtle Doves, based on information provided by Marchant et al (1990), Siriwardena et al (1998) and Browne & Aebischer (2003c). These phases corresponded to a period of population increase (1961-75), stability (1976-85) and decrease (1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000).…”

The role of cultivated versus wild seeds in the diet of European turtle doves (Streptopelia turtur) across European breeding and African wintering grounds

“…This has been suggested to be linked to reduced food availability, making it harder for adults to reach and maintain adequate body condition for breeding, resulting in a shorter breeding season (Browne & Aebischer, 2001). Whilst this has not been proven in turtle doves (Browne & Aebischer, 2003b), a reduction in wild food availability early in the breeding season, when nutritional demands to reach breeding condition are highest, occurred concurrently with a dietary switch to a greater proportion of cultivated seed (Browne & Aebischer, 2003a), making this a plausible cause for reduced breeding attempts in the UK. As crop plants do not provide seeds until later in the breeding season, restoration of early‐flowering wild plants in the environment is essential for the species to provide seed‐rich habitats.…”

“…There has been a shift in the diet of turtle doves in the UK since the 1960s. The prevalence of seeds of non‐cultivated arable plants declined from 95% in the 1960s (Murton et al., 1964), to just 40% in the 2000s (Browne & Aebischer, 2003a, 2003b), replaced by the seeds of cultivated crops, principally wheat ( Triticum sp.) and rape ( Brassica ).…”