Inland pastures are an appropriate alternative for salt-marshes as a feeding area for spring-fattening Dark-bellied Brent Geese Branta bernicla

On the Dutch Wadden Sea island Texel, spring-fattening Dark-bellied Brent Geese Branta bernicla fed almost exclusively inland on improved grasslands, whereas the remainder of the flyway population utilised coastal saltmarshes elsewhere in the Wadden Sea. There are indications that inland pastures are 'second choice habitat' during this important period. During spring-fattening, salt-marsh food plants just started to grow, offering the geese high quality food, while the growth of grasses on the inland pastures started earlier in the season, so that the nutritional value of inland grasses declined in the course of the spring-fattening period. This paper describes the habitat use of spring-fattening Dark-bellied Brent Geese on Texel and compares the reproductive output of pasture feeding and salt-marsh feeding geese. Dark-bellied Brent Geese on Texel overcame the problem of declining grass quality on inland pastures by tuning their grazing pressure to the plant production in such a manner that they kept the grass in the young, protein rich phase. Observations of individually marked Dark-bellied Brent Geese revealed the site-fidelity of spring-fattening geese on Texel. The annual survival of a sample of Texel geese (89%) was slightly higher than published values for the whole population (86%). Between 1982 and 1993, Dark-bellied Brent Geese successfully bred in six years, while the reproductive success of inland pasture feeders and salt-marsh feeders was similar. The calculated lifetime reproduction of Dark-bellied Brent Geese spring-fattening on Texel amounted to 1.39 offspring per goose, which was in accordance with overall population trends during the period concerned. The results show that an improved grassland reserve can be an appropriate alternative for salt marshes for spring-fattening Brent Geese.