Collared Doves (Streptopelia decaocto) in Urban Habitats

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Abstract
Collared doves S. decaocto (Frivaldszky) were studied in 2 industrial areas, Ellesmere Port, Cheshire and Trafford Park, Manchester. Both sites were primarily feeding places, and the birds obtained their food in the form of spillage and stored products from processing factories, mills and warehouses; in these circumstances the food supply is reasonably constant throughout the year. Data on breeding was gathered at a semi-rural site at Soham, Cambridgeshire. At Ellesmere Port, collared doves roosted close to food sources. Peak numbers occurred in winter and, during the first 4 yr of the study, tended to increase annually, reflecting increasing food supplies. Following drastic building changes, which affected roosting and feeding areas, the population declined. Adults and juveniles tended to move less than those at Trafford Park, suggesting a stable population. At Trafford Park, collared doves roosted throughout the suburban areas of southwest Manchester in a radius of about 7 km around the main study site. During the 6 yr of the study, peak numbers and remained relatively constant, fluctuation being caused mainly through food shortages at subsidiary feeding places or through spillage clearance schemes. In contrast to Ellesmere Port, peak numbers occurred in summer when surplus birds from the surrounding area joined the main feeding flock. Analysis of ringing recoveries by the British Trust for Ornithology reveals that juveniles are more likely than adults to leave places where they were 1st captured. There was no clear seasonal pattern in the movement, but most were towards the north/southwest compass segment. The calculated annual adult and juvenile mortality was 39 and 69%, respectively. Shooting probably accounted for most mortality and there was evidence that the rate increased during the breeding season. Collared doves were in reproductive condition from March-Sept. with maximum gonad size corresponding to the peak period of egg laying. At Soham an average 42% hatched with a maximum of 69% in July and Aug. Egg failure was largely from predation. Overall breeding success was 26% and calculated mean annual productivity was 2.5 young per pair. The seasonal molt begins in March and lasts 9 mo. with breeding and molting occurring simultaneously as in other pigeon species. Economic problems of collared doves in a man-made niche are briefly discussed, as is the continued tendency for doves to move in a northwesterly arc. Implications of the retention of a photoperiodic breeding season and of seasonal variations in egg-hatching success are also discussed.

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