Food intake, body reserves and reproductive success of barnacle geese Branta leucopsis staging in different habitats

• Main Authors: Prop, J., Black, J.M.
• Other Authors: Mehlum, F., Madsen, J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Norsk Polarinstitutt 1998
• Subjects: BELLIED BRENT GEESE; LESSER SNOW GEESE; NUTRITIONAL-REQUIREMENTS; SPRING MIGRATION; CANADA GEESE; ANNUAL CYCLE; B-BERNICLA; JAMES-BAY; PERFORMANCE; PROTEIN; Canada; Helgeland; Norway; Arctic; Branta leucopsis; brent geese; James Bay; Spitsbergen
• Online Access: https://hdl.handle.net/11370/451493f0-dfa5-4268-9875-068287e7a6d6; https://research.rug.nl/en/publications/451493f0-dfa5-4268-9875-068287e7a6d6; https://www.rug.nl/research/portal/files/2980876/c4.pdf

This paper concerns the effect of habitat choice on the dynamics of deposition of body reserves in spring-staging barnacle geese Branta leucopsis. On their way to breeding areas in Spitsbergen, these geese reside for several weeks on islands off the coast of Helgeland, Norway. They use three distinct habitat types: (1) managed islands, which are covered by Hay meadows fringed by salt marsh vegetation and where grazing by livestock occurs; (2) abandoned islands, where in the absence of people the vegetation on the upper parts of the islands has developed towards communities dominated by tall herbs; and (3) agricultural islands, where pastures are the mainstay for the geese. In each of these habitats data were collected on intake and digestibility of food components. Habitat-mediated differences in the birds' foraging performance resulted in large variation in the accumulation rate of fat and protein reserves. Total body reserves deposited by birds on abandoned islands were 11% less than reserves deposited by birds in a managed habitat. Geese on agricultural islands deposited much larger fat reserves than birds in the other habitats, whereas their protein reserves were smaller. Fat deposition rates in the three habitats were related to different levels of digestibility and ingestion rate of the food. The probability of raising offspring through to autumn was positively related to the fat scores that individuals had achieved by the end of the staging period. However, this was not the case for geese staging in agricultural habitat, possibly because the small amounts of protein accumulated may have prevented the development of a sufficiently strong muscle system. Creating reserves on agricultural land to accommodate geese in spring may therefore have negative consequences on the birds' reproductive performance.