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| Previous work has shown that High Arctic
waders in Greenland are “income breeders”, i.e. the
resources used for egg formation are based almost
entirely on biomass obtained on the breeding grounds.
Thus, their breeding phenology is expected to be
highly sensitive to inter-annual variation in food abundance
during the pre-laying period. Early spring snowcover
may also inXuence timing of egg-laying either
directly or mediated through food resources. Here, we
report on the inter-annual variation in clutch initiation
of three wader species breeding in High Arctic Greenland,
Sanderling (Calidris alba), Dunlin (Calidris alpina)
and Ruddy Turnstone (Arenaria interpres), in
relation to spring snow-cover and spring arthropod
abundance over ten breeding seasons at Zackenberg
Research Station 1995–2005. Food abundance had the
strongest eVect on timing of clutch initiation, while the
proportion of snow-free land had a weaker but still signiWcant
eVect, i.e. more food and more snow-free land
both result in earlier egg-laying. We hypothesize that
food is most important when there is suYcient snowfree
land to nest on, while snow-cover is of increasing
importance in years with late snowmelt. | |
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