The report contains:
In 2000 a WIWO expedition was organised to the remote Taimyr Peninsula, which is situated in the high north of Siberia Russia. Members of this expedition were Sergei Khomenko (Ukraine) and Raymond Klaassen (Netherlands). The expedition was organised in close co-operation with two workers of the Dutch institute 'Alterra' and 5 Russian researchers.
We stayed at the convenient Willem Barenz Field station, which is situated 18 km south of Dikson in the Medusa Bay area. The field station was built with financial help from the Dutch Ministry of Agriculture, Nature Management and Fisheries in 1994. From 1996 on WIWO expeditions were carried out to this area (Tulp et al, 1997; Khomenko et al, 1997; Felix & van Turnhout, 2000; Willems & van Kleef, 2000).
Aims of this year expedition were continuing of the in 1998 developed standardised bird monitoring program (Van Turnhout et. al, in prep.) and study wader breeding ecology.
Incubating Little Stint Calidris minuta
The total study area consists of a 30 km2 stretch of coastal arctic tundra near Medusa Bay, located at the northern end of the mouth of the Jenessei River. Small rock formations are protruding above the tundra surface. Several small rivers start flowing by the end of June through the area, taking snowmelt water to the sea. Vegetation can be classified as arctic tundra (Chernov, 1985) characterised by a short vegetation (less than 10 cm), dominated by mosses, Dwarf birches (Betula nana), sedges and grasses. The intense part of the monitoring and the wader breeding ecology studies were carried out in a small 4 km2 plot. The Medusa River forms the natural southern border of this plot.
The so called "Polygoon" tundra
Upon arrival at 6 June an unexpectedly large part of the area was already free of snow (only 50% snow coverage), caused by an early period of warm weather in May, according to local people. June however was exceptionally cold with mean temperatures hardly rising above freezing point and lots of snow showers. In contrast, July was very warm compared to other years with maximum temperatures of 21°C and very little precipitation. On warm days with southerly winds mosquitoes arrived from the south. The summer was extremely warm in other parts of the Russian arctic too, at one location on the polar circle in Russia even a heat wave was recorded.
Arctic Foxes and Lemmings
In 2000 Arctic Foxes were abundant. Almost every day foxes were observed in the study area, up to 3 different foxes per time. Lemmings instead were not abundant. In the first month not more than one lemming per week was observed. Later in the season lemming number seemed to be increased, because almost every day a (mostly juvenile) lemming was observed.
The Willem Barenz Field station
Aim of the in 1998 developed monitoring program is to reveal temporary changes in local numbers of arctic breeding birds. Furthermore this monitoring can give a better understanding of the complex relationships between predators and prey in the arctic community. Therefore not only birds are monitored, but also several biotic and abiotic factors.
Bird migration and arrival were monitored by fixed point counts and daily standard route counts. The fixed points counts for example showed that backward migration of the Pomarine Skuas already started at the 12th of June. This reflects the situation in the field, where Pomarine Skuas did not breed due to low Lemming numbers. Route counts appeared to be useful to monitor wader arrival.
Breeding bird numbers were monitored using territory mapping in three plots. Abundant species were counted in a 4 km2 plot (for example Little Stint, Dunlin, Snow Bunting). Less abundant species were counted in a 12 km2 plot (for example Pacific Golden Plover). In a 30 km2 plot rare species were monitored (for example Snowy Owl, Rough Legged Buzzard).
Breeding bird numbers in the 4 km2 plot (the only plot from which data are analysed yet) were comparable to numbers found in 1998 and 1999. Dunlin number seems to be stabilised after an increase since 1996 (data in 1996 were obtained in a slightly other way). Ptarmigan and Pacific Golden Plover were more abundant compared to other years. Snow Bunting was less abundant as in previous years.
For Little Stint and Curlew Sandpiper the used monitoring method does not seem to work due to the fact that these species are easily missed in the field. The monitoring results in a severe underestimate of territory numbers, and the monitoring is not repeatable for these two species.
The monitoring did not seem to be greatly influenced by the high predation rate of nests by Arctic Foxes. However it should be noticed that territories are based on less observations.
Nest success was monitored. Because of the heavy egg predation by Arctic Foxes and Stouts, nest success was very low this year. Survival of a nest for the whole incubation period varied between 0.03% (Curlew Sandpiper) and 47% (Snow Bunting).
Other variables monitored beside bird density and nest survival were snow coverage, arthropod availability and phenology of plant flowering.
Melting snow ridge
Besides monitoring activities the Dutch WIWO participant was also involved in the Alterra activities (and the other way around). Because results from this research will be included in a combined WIWO/Alterra report, activities carried out shortly will be outlined here.
With a special designed clap net, playing sound and dummy birds we tried to catch newly arrived and departing waders to obtain knowledge about the condition of arriving and departing waders. An assumption in models describing migration strategies is that arriving early and in good condition is beneficial for reproduction. However, field data confirming this hypothesis are still lacking. Only few arriving birds were caught, instead of many departing birds which reacted much stronger on sound display and dummy birds. Although data are not analysed yet, we had the impression that most birds were migrating with very little fat, suggesting a migration strategy consisting of small laps.
In 1996 energy expenditure of incubating Little Stints was measured at Medusa Bay with the doubly labelled water method. This year we carried out similar measurements on chick-rearing individuals, combined with time budget observations. In this way the energy expenditure of incubation and chick- rearing can be compared. We obtained successful measurements on 12 birds with chicks aged between one and eight days.
Because the Little stint and the Curlew sandpiper are solitary breeders a trade-off exists between egg incubation and feeding time. To investigate this, temperature sensors were used to record time spend breeding (and time spend feeding). In total 77 recordings were taken at Little Stint nests and 10 at Curlew Sandpiper nests.
- Summary in English and Russian and introduction
- Description of the study area
- Chapters on monitoring details, studies on shorebirds, lemmings and predator abundance
- Composition of feeding menu of passerines
- Biometry of growing Snow Bunting chicks
- Taimyr Herring Gull colony structure
- Spring migration of White-fronted and Brent Geese
- Avifaunistic and mammal notes
- Appendices on dayli migration count results, colour ringed Dunlins and Pacific Golden Plovers, and phenology of plant flowering