A Review of Rook Status, with New South Pembrokeshire Data, 1986 - 1996
Field Studies, 10, (2001) 37 - 56 A REVIEW OF ROOK STATUS, WITH NEW SOUTH PEMBROKESHIRE DATA, 1986 - 1996 DAVID I. LITTLE , ANNETTE E. LITTLE 28 School Lane, Swavesey, Cambridgeshire CB4 5RL AND DAVID LEVELL 5 Westgate Hill, Pembroke, Pembrokeshire, Wales, SA71 4LB ABSTRACT The rook population of southern Pembrokeshire was surveyed using nest counts during two breeding seasons, ten years apart (1986 and 1996). The results were compared over the study period, and analysed with reference to published data for this and other regions. The rookeries were non-randomly distributed, mainly on mixed farmland with limestone soils. Changes in the numbers of rook nests through time were variable within the study area, ranging from nest increases of over 30% in the south-west (Dale, Angle and Castlemartin), to decreases of 47% in the south-east of the county. The average size of rookeries was stable in the south, increased in the west, and decreased in the east. The overall size distribution of rookeries did not alter much between 1986 and 1996, and was similar to that seen in Pembrokeshire in 1975. The number of individual rookeries decreased by as much as 53%, except on the Castlemartin peninsula where an increase of 38% was noted. Overall, there was a slight decrease in total rook nest numbers of about 7% between the two south Pembrokeshire surveys. In contrast, at the national (UK) level, there were estimated increases of about 7% between 1975 and 1980. Subsequent national increases ranging from 5% to 14% were suggested by a combination of results of the Common Birds Census (CBC) and the Breeding Bird Survey (BBS), over the period 1986-1998.
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