Observations of a White-tailed Eagle incubating eggs of a Greylag goose

Abstract

Interspecific takeovers of nests are thought to be rare in birds. A female White-tailed Eagle Haliaeetus albicilla was observed incubating a nest of a Greylag Goose Anser anser with five eggs at Reinøya, Troms County, Norway in 2021. There were no signs of any killed geese in the area around the nest, and there had been no observations of interactions between the two species at the site before the eagle started incubating the eggs. The nest was discovered in the middle of May but was abandoned around midsummer. A similar case reported from the Isle of Mull, Scotland in 2017 was the first of its kind and originally believed to be unique, but the new case in Norway in 2021 suggests that interspecific nest takeover may not be as unusual as previously believed. Anser anser, Haliaeetus albicilla, interspecific nest takeover, Norway, Scotland