Behavioural ecology of the lapwing Vanellus vanellus L. in Upper Teesdale
From 1993-95, the behavioural ecology of the lapwing Vanellus vanellus L. was studied in Upper Teesdale, Co. Durham, with the aim of describing the behavioural mechanisms underlying some population characteristics. Significant effects of age and individuals were found in many aspects of Lapwing breeding biology. Older Lapwings returned to the breeding grounds before yearlings, with adult males returning earliest of all. First breeding attempts occurred at one-year-old for most females, but at two-years-old for most males. Males two-years-old and over showed a remarkable degree of consistency in breeding status (breeding or non-breeding) in consecutive years, even where this meant persistent non-breeding. The age of first breeding, and consistency of breeding status among males, indicates intense intermale competition for limited breeding habitat, with some males, perhaps of low quality, apparently permanently prevented from breeding. However, few differences in annual breeding success were found among females of different ages. With the exception of egg size in first clutches, where yearling females laid eggs around 5% smaller than adults, yearling and adult females were similarly fecund. Laying dates and egg volumes in first clutches exhibited high indices of repeatability between years, probably reflecting a high degree of heritability of these traits. High frequencies of polygyny were recorded, despite the traditional view of strict monogamy for this species. The mating success of male Lapwings increased between one and three years-of-age. The distinct parental roles of the sexes facilitated the occurrence of polygyny by reducing activity-budget costs of polygynous associations for both sexes. Polyterritoriality, polyandry and double-brooding were also recorded and discussed.