Spatial and temporal feeding segregation of two Icelandic goose species during the spring pre‐nesting period

• Published in: Ecography
• Main Authors: Fox, A. D., Boyd, Hugh, Warren, Stephanie M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1992
• Subjects: Ecology, Evolution, Behavior and Systematics; Iceland
• Online Access: http://dx.doi.org/10.1111/j.1600-0587.1992.tb00037.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-0587.1992.tb00037.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0587.1992.tb00037.x

The pre‐nesting feeding behaviour of greylag Anser anser and pink‐footed geese A brachyrhynchus was studied on agricultural land at low altitude in southern Iceland from 10 April to 8 May 1990 Greylag geese were already present on 12 April increased to 4580 birds by 24 April, but declined to 1300 by 3 May Pink‐footed geese arrived around 20 April and numbers continued to increase to a peak count of 11340 on 3 May Over 60% of greylag geese initially used stubble fields on the coast where this habitat was most frequent, but increasingly resorted to grassland and wetland habitats during late April Later‐arriving pink‐feet predominantly used managed grassland, away from coastal areas At inland grassland sites, greylag numbers peaked on 20 April, pink‐feet m early May The early exploitation by greylags was associated with grass growth initiated under protective snow‐patches Greylags spent 90 times more time feeding within 1 m of snow patches with enhanced grass growth than expected by chance and their feeding rates near snow patches were faster and their step rates slower than further away By early May, grass growth was uniform and, although snow‐patches persisted, no difference in forage quality, goose feeding rates or step rates could be detected It is concluded that, in spring 1990 at least, habitat segregation during spring migration in southern Iceland minimised competition between these two closely related goose species within the same geographical area In areas where both species exploit the same habitat, a two week difference m timing of breeding (and hence phenology of migration) further assures minimal overlap in feeding exploitation