BREEDING AND MOLTING SHELDUCK (TADORNA-TADORNA) OF THE SEVERN ESTUARY

Aerial and ground censuses of Shelduck in 1988 found a summering popul ation of 2000-2700 birds until early july. Territorial pairs, non-bree ding aggregations and ultimate brood rearing nursery areas were associ ated with extensive areas of mudflats (Peterstone Wentlooge, Uskmouth- Collister Pill, Oldbury-Littleton and Purton-Frampton). Bridgwater Bay continues to be the most important moulting area away from the Wadden Sea, with just under 2000 present at peak count in late July. At leas t 94 pairs established territories along the shores of the Severn, wit h perhaps as many as 80 more on Flatholm, giving rise to at least 49 b roods. Duckling survival was low in 1988: mean brood size fell from 9. 3 to 3.3 between hatching and fledging. Breeding success in different parts of the estuary shows no consistent trends.