The Effects of Agricultural Land-Use on the Breeding Ecology of Lapwings Vanellus vanellus

The primary aim of this project was to investigate the relationships between agricultural land-use and the breeding ecology of Lapwings by comparing breeding biologies in two different habitats - arable farmland and rough grazing. Both land-use policy and specific farming operations have important effects on all aspects of Lapwing breeding biology, including nesting habitat choice, timing of laying, clutch and egg sizes, hatching and fledging success. In the first two years of the study, productivity on the arable site was too low to maintain the population. This was due to a combination of timing of farming operations, crop growth and habitat availability. In the final year, poor weather in the early spring disrupted cultivation and retarded crop growth and breeding success on the arable site was comparatively high. In all three years productivity on the rough grazing site was sufficient to maintain the population (in spite of a higher level of predation). The difference between the two sites was due to their markedy different land-use policies. A secondary aim of the project was to investigate the possibility of behavioural limitation of breeding density and success in Lapwings. Lapwings on the rough grazing site apparently compete tor high quality habitats which they occupy preferentially and within which breeding success and nesting density is high. Lower quality habitats, in which breeding success and population density is reduced, are filled later. These results conform to the predictions of the ideal despotic model and suggest that a mechanism exists whereby behavioural limitation might take place. The conservation and population dynamics implications of these findings are discussed