In 2005 an expedition of the Working Group International Waterbird and Wetland Research (WIWO) visited the Medusa Bay area, near Dikson on the Taimyr peninsula, in northern Siberia (Russia), at 73o23’N 80o32’E . The main aim of the expedition was to apply a standardized breeding bird monitoring method intended to reveal temporal changes in breeding bird numbers at Medusa Bay. This will improve our knowledge of population dynamics of waders and other bird species. The main goal of the monitoring programme is to focus on numbers of all bird species present within fixed plots. Furthermore some important demographic variables, being nest success, environmental variables (snow cover, temperature) and biotic variables (lemming and Arctic fox abundance, arthropod availability) are monitored to be able to explain changes in breeding bird numbers and breeding success. Apart from carrying out the monitoring scheme, research activities also included research on breeding ecology of Brent Geese in relation to Snowy Owls, which was a continuation of the research performed in 1999.
The breeding season of 2005 at Medusa Bay can be characterised as a typical ‘lemming year’ in the three-year lemming cycle. Lemmings were abundant at the start of the season and steadily declined probably due to predation. Avian lemming predators and Arctic foxes were breeding in the study area. Compared to previous lemming-years (1996, 1999) numbers of Snowy owl were low in the study area, resulting in low numbers of breeding Brent Geese which prefer to breed near the owls. Numbers of Pomarine skua and Rough-legged buzzard were comparable to other lemming years, but with remarkable difference in the behaviour of the skuas. Numbers of breeding waders are relatively stable, with the exception of Dotterel an Ruff (both only recorded in 2001), Curlew sandpiper (fluctuating yearly) and Pectoral sandpiper and Grey phalarope (both influx in 2001 and declining afterwards).
The study on Brent Goose breeding ecology revealed that they were primarily breeding in association with Snowy Owls in the Medusa river catchment on western Taimyr, Russia. Goose nest failure, either as a result of nest abandonment by the adult birds or of nest depredation, increased with increasing distance from the owl nests. Within the Brent Goose colonies, clutch size as well as egg size increased with decreasing distance from the Snowy Owl nest, indicating an increasing adult quality closer to owl nests. However, as a result of the abandonment of eggs and goslings, the increasing clutch size did not result in a higher nest success during this study. Apparently Brent Geese compete for breeding sites close to owl nests.
It is of great importance that the monitoring scheme is continued in the years to come. The programme will provide insights in fluctuations and (long-term) changes in numbers of breeding birds and their breeding success as well as in the factors explaining these. Results of monitoring programmes like the one presented here are of crucial importance for a proper management of the Great Arctic Reserve and the Arctic in general, as well as for the management of all natural areas along the migration routes of the bird species, for example in western Europe and Africa.
Furthermore, the report contains:
- Avifaunistical notes
- Phenology of plant flowering
- Ringing data
- Field map with latitude coordinates of the stick transect
- Vegetation map of the study area