Part I. Development of the wildfowl population

Abstract

Data are presented for a continuous series of daily or weekly counts from 1956 to 1967. Mallard constituted the bulk of the wildfowl population, and steady increases have been recorded since the reserve was established. Results suggest that the encouragement of natural breeding by Mallard plays a more important part in establishing a local population, especially during the summer, than does the release of hand-reared birds. However, the first breeding records for Tufted Duck were obtained following the release of hand-reared birds, although the latter could not be definitely established as a prime factor of this development. The numbers of diving duck species in general increased rapidly following the cessation of gravel extraction from one of the two pits. The number of species recorded annually has increased markedly since 1956. A maximum of seventeen was recorded in the severe winter of 1962-63; a total of twenty-one species of wildfowl has been recorded within the reserve, not including introductions or escapes.