A study of the waterfowl populations on Lough Carra, County Mayo, 1967-2006

Abstract

This study examined the population fluctuations of nine waterfowl species on Lough Carra in County Mayo by comparing count data from two waterfowl counting programmes conducted from 1967 to 1980 and 1995 to 2006 It also examined the population fluctuations of a further six waterfowl species from 1995 to 2006 To add to existing population data, a total of 36 waterfowl counts were conducted as part of the study over 22 months from November 2004 to August 2006 Comparative breeding surveys on ten islands on the lake were undertaken during 2005 and 2006 to compare current breeding populations to those from 1968 to 1973 To develop hypotheses in relation to the decline in the populations of certain species, predation and negative habitat changes were investigated The research for this element of the study included island vegetation mapping, reedbed analysis and the investigation into habitat changes m two of the lake’s sub-catchments This study found that seven duck species have severely declined on Lough Carra smce the 1960s/70s with Teal (Anas crecca), Pochard (Aythya ferina) and Mallard (Anas platyrkynchos p) populations down by 91%, 89% and 88% respectively. The once nationally recognised Mallard breeding population has crashed largely due to high levels of predation and the loss of breeding and feeding habitat The American Mink (Mustela visori) has predated the nests of Mallard and Tufted Duck (Aythya fuhgula) but evidence also shows that it preys upon adult and juveniles of those species as well as Moorhen (Gallinula chloropus) and Teal Using recognised scientific methods, this study has highlighted the large-scale declines in the populations of waterfowl on Lough Carra, it has provided important data which will contribute to future management and in addition to building upon previous studies, lays a new foundation for further research at the lake