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Publication number 52. Stichting WIWO

Title: Breeding birds of Cape Wastochnia, Pyasina Delta, Taimyr, Russia, in 1994
Authors: Holmer Vonk
Publication date: 2003


Summary

As expected from observations made in earlier years, the breeding season of 1994 was a peak year in lemming densities. Lemmings normally show a three-year cycle in abundance. With the last peak year at Cape Wastochnia being 1991, this pattern also occurred in the study area. Arctic Fox was also present with one occupied burrow at the eastern border of the study plot.
As a result of the lemming densities, the typical lemming predators Snowy Owl, Pomarine Skua and Rough-legged Buzzard were breeding in the area. The breeding of some species, at least White-fronted Goose, also seems restricted to lemming peak years in the area. Most non-predatory species also occurred in 1993. Breeding densities were comparable in both years. The density of lemmings thus not seems to influence the number of birds which start breeding. However, in this differences between methods and observers should be taken into account. Densities found in 1994 should be considered as the absolute minimum of the numbers actually present and might actually give some underestimation for the smaller wader species.
At least 19 species have been breeding in the area, of which of 15 species nests were searched for and found. Of these 15 species 185 nests, 8 additional broods and 3 additional nest-indicating pairs were found in total. Little Stint was the most frequently found species with 95 nests. Of the 132 nests of which the outcome is known, 108 (82%) hatched, 13 (10%) were predated and 11 (8%) deserted for various reasons. If the nests of Little Stint are excluded in this calculation, 73% hatched. The overall breeding success thus was high in 1994. Only close to the Arctic Fox burrow a significant part of the nests failed because of predation. Besides this, the low temperatures and strong winds after 10 July might have caused a relatively high percentage of deserted nest.
Overall the breeding season of 1994 at Cape Wastochnia has been a favourable season, typical for lemming peak years.

The report contains:
  • Introduction and conclusions
  • Description of the study area, weather conditions etc.
  • Aims and methods
  • An account of breeding birds
  • Biometrics of caught birds
  • Appendix with moult scores