LONG-TERM REPRODUCTIVE-PERFORMANCE IN WHITE-FRONTED GEESE ANSER-A-ALBIFRONS AND TUNDRA BEAN GEESE ANSER-FABALIS ROSSICUS WINTERING IN ZEELAND (THE NETHERLANDS)

The reproductive performance of White-fronted Geese and Tundra Bean Ge ese was surveyed during 1964/65 to 1994/95 in southern Zeeland (the Ne therlands). The proportion of first-year birds was higher on average i n the White-front than in the Tundra Bean Goose (29 +/- 10% and 25 +/- 5%) and mean brood-size was also higher (2.5 +/- 0.3 versus 2.1 +/- 0 .2). During the first five years of the survey, more than 15% broods i n both species were single-parent, this proportion dropped to 5-10% in the course of the 1970s. No trend in time in reproductive parameters of either species was found. The proportion of first-year birds was si gnificantly correlated with mean brood-site in both species. In the Wh ite-fronted Goose both parameters show a pattern of poor breeding ever y three years and the proportion of first-year birds is strongly corre lated with those of the Dark-bellied Brent Goose. No cyclical variatio ns were found in the Tundra Bean Goose, perhaps because its breeding r ange is more southerly than that of the White-front.