Breeding ecology of a suburban population of Woodpigeons Columba palumbus in northwest England

The Woodpigeon Columba palumbus attracts attention as an agricultural pest (Inglis et al. 1989, 1990, 1994, 1997) and quarry species (Willock 1995, Harradine & Reynolds 1997) and because its numbers have increased greatly in recent years. The expansion of arable farming during the 19th century has assisted this rise in numbers (Marchant et al. 1990). A decline in Woodpigeon numbers occurred during the 1950s and 1960s. This was attributed to the loss of winter clover Trifolium leys, which provided food (Inglis et al. 1990, 1994). However, since the mid-1970s, the Woodpigeon population has increased and this has been attributed to the introduction of oilseed rape Brassica napus as an arable crop (Inglis et al. 1990, 1994, 1997). The population increase has resulted in an increase in the breeding of the species in suburban and urban areas (Hardy 1985–98, 1986, Slater 1995). The number of gardens being visited by Woodpigeons as part of the British Trust for Ornithology (BTO) Garden Bird Feeding Survey (GBFS) has also increased (Glue 1993, 1995, 1997). During the winter of 1996/97, Woodpigeons reached their highest ever feeding level in GBFS gardens since the start of the survey in 1970, the species being recorded in 54% of the gardens covered. BTO Common Bird Census (CBC) data show an increase in the index for Woodpigeons between 1973 and 1997 (Wilson & Marchant 1997, Marchant et al. 1998). In the same way, the Breeding Bird Survey (BBS) shows the Woodpigeon to be one of the most abundant species (Gregory & Bashford 1995, 1996). Most of these surveys tend to take place during the period April to June, before most Woodpigeons have started to breed, whereas the main breeding season of the Woodpigeon is July to September (Inglis et al. 1994, Murton 1965, Slater 1997). Also, CBC data only give an indication of the number of birds holding territory in woodland and farmland and not the number of birds present in suburban areas, or of their breeding success. This study has determined that Woodpigeons in suburban areas can breed at densities as high as those found in some farmland and that they can have a higher breeding success. Hatching and fledging success of Woodpigeons breeding at Sefton Park in south Liverpool is described. The nesting site preferences of Woodpigeons are examined. Ringing recoveries have shown that birds reared in suburban areas do move out to agricultural land (Merseyside Ringing Group Annual Reports 1993–95). It is also believed that, in this particular study, many adult birds fly out to feed upon farmland (minimum 6 km) during the breeding season (unpubl. data). Most work on Woodpigeons involved studies of rural populations by the Ministry of Agriculture, Fisheries and Food (MAFF) (Inglis et al. 1989, 1990, 1994, 1997, Murton 1958, 1965). Most of the studies were carried out before the large-scale introduction of oilseed rape as a major crop. The study site was Sefton Park (grid reference SJ377875) at Aigburth, Liverpool, located approximately 4 km to the southeast of Liverpool City Centre. The park comprises approximately 250 acres of parkland and is composed mainly of areas of short grassland with clumps and avenues of trees. There are approximately 4200 trees in the park (Liverpool Planning Department pers. comm.) of a variety of species and ages. Several watercourses flow sluggishly through the park. The park is bounded by the densely built-up Bird Study (2001) 48, 361–366