Breeding ecology of the Magellanic penguin at Cabo Virgenes, Argentina: What determine reproductive success?

FRERE, E.; GANDINI, P. & D. BOERSMA

WATERBIRDS (DE LEON SPRINGS, FLA.)

WATERBIRD SOC

Año: 1998 vol. 21 p. 205 - 210

1524-4695

We studied factors that may determine the annual variation on reproductive success of Magellanic Penguin (Spheniscus magellanicus) at Cabo Virgenes, Argentina during three breeding seasons (1989/90, 1990/91 and 1991/92). Six areas containing approximately 150 active nests were established. Reproductive success, measured by the number of chicks fledged per active nest, was highly variable among years (0.83, 0.19 and 0.58). During the three seasons, the hatching and fledging weights, feeding frequency, number of chicks starved, chick growth rates and proportion of nests with two fledglings did not chang significantly. However, nest desertion rate, nest predation and weather conditions (winds, minimum temperatures, rainfalls and snowfalls) showed great variability among seasons. Our results show that extremes in weather conditions at Cabo Virgenes, limit breeding success in penguins, causing high nest desertion rates and chick mortality.