The ecology and spatial dynamics of wintering waterfowl on Lough Neagh

Abstract

Lough Neagh, the largest freshwater lake in the British Isles, regularly hosts internationally important numbers of waterfowl, the most numerous being the diving ducks. The behaviour, movements and feeding ecology of Pochard Aythya ferina, Tufted Duck A. fuligula, Scaup A. marila and Goldeneye Bucephala clangula were investigated during the winters of 1996-99. Diurnal behaviour studies revealed that the Aythya species mainly roosted throughout the day, whilst Goldeneye mainly spent the day feeding. Aythya males outnumbered females and differential migration of the sexes is the likely explanation. Recoveries of ducks ringed or recovered in Northern Ireland showed similar migration patterns to ducks ringed in Great Britain, although very few have been recovered on Lough Neagh.

Dietary analysis of stomach contents revealed chironomid larvae, associated with the deep muddy sediments of the Lough, as the most abundant prey type taken for all diving duck species.

Shooting disturbance was identified as the dominant winter recreation activity on Lough Neagh, affecting the seasonal, weekly and daily distributions of diving ducks. The disturbance caused them to re-distribute by either moving to the shoreline refuges where they were sheltered from the prevailing south-westerly wind, or to move to areas >500m from the shore where disturbance no longer affected them. A comparison of diurnal activity rhythms under refuge and non-refuge conditions showed an increase in the proportion of time Pochard and Tufted Duck spent feeding after the close of the season. However, this was attributed to the need to accumulate fat prior to migration, and not due to the cessation of shooting disturbance. Furthermore, given that the Aythya species mainly feed at night and in the deep, muddy areas of the Lough (away from the shoreline), it is expected that any adverse energetic consequence caused by disturbance is likely to be small.

Date of Award	Oct 2000
Original language	English
Supervisor	KEITH DAY (Supervisor)