Breeding ecology of Turtle Doves Streptopelia turtur in Britain during the period 1941-2000: an analysis of BTO nest record cards.

Abstract

Capsule No trends over time were detected in any aspect of Turtle Dove breeding ecology and only slight regional variation, based on individual nesting attempts recorded.
Aim To present information on the breeding ecology of Turtle Doves and identify any temporal or regional trends that may have contributed to the decline of the species.
Methods Information on nesting habitat, type of bush used, nest height, clutch size, brood size and nest outcome was extracted from 1925 Turtle Dove nest record cards from 1941 to 2000, and examined for temporal and regional trends.
Results The majority of Turtle Doves nest in thorny trees within scrub habitats, where mean nest height was 2.27 ± 0.02 m. Mean first-egg date was 18 May ± 1 day (annual range 28 April to 26 May). Mean clutch size was 1.84 ± 0.01 (annual range 1.65-1.93), producing a mean brood size of 1.82 ± 0.01 (range 1.50-2.00). Based on the recorded fate of individual nests, 41.3 ± 1.4% were successful, 44.9 ± 1.7% were predated and the rest (13.9 ± 1.4%) were lost to other causes. Nest survival rate averaged 0.577 ± 0.019 during the 14-day incubation period and 0.771 ± 0.019 during the 15-day nestling period giving an overall rate during the entire nesting period of 0.445 ± 0.018. Although there was some significant variation in these parameters between time periods and regions, there were no significant linear trends during the period 1941-2000.
Conclusion The population decline experienced by Turtle Doves breeding in Britain is not due to lower success of individual nesting attempts. If breeding productivity has played a role in the decline, it must be through a reduction in the average number of nesting attempts per pair.