Long-term reproductive performance in White-fronted GeeseAnser a. albifronsand Tundra Bean GeeseA. fabalis rossicuswintering in Zeeland (The Netherlands)

Abstract

The reproductive performance of White-fronted Geese and Tundra Bean Geese was surveyed during 1964/65 to 1994/95 in southern Zeeland (the Netherlands). The proportion of first-year birds was higher on average in 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% of broods in 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 significantly correlated with mean brood-size in both species. In the White-fronted Goose both parameters show a pattern of poor breeding every three years and the proportion of first-year birds is strongly correlated with those of the Dark-bellied Brent Goose. No cyclical variations were found in the Tundra Bean Goose, perhaps because its breeding range is more southerly than that of the White...