Bag Sizes of Waterfowl in New-South-Wales and Their Relation to Antecedent Rainfall

Abstract

Bag sizes of game ducks in New South Wales between 1977 and 1984 were compared with antecedent annual rainfall in eastern Australia. Mean bag size is equivalent to 'catch-per-unit-effort', an index of population abundance. Annual rainfall is an index of habitat availability for waterfowl. Bag sizes of Pacific black duck and all game species combined were significantly (P<O.05) related to antecedent rainfall. Rates of increase (computed from annual catch-per-unit-effort) of black duck, maned duck and all species combined were significantly related to rainfall difference between the preceding 2 years. This study indicates that prior rainfall is a useful predictor of duck numbers in New South Wales.