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RESPONDENT
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Irina Menyushina
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SITE NAME
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Neizvestnaya River upper reaches, Wrangel Island, Russia
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| Contact details
(phone/fax//e-mail//address): |
| (495)687-06-57 // v.n.ira@mail.ru // Prospect Mira, 103-109, Moscow, 129085, Russia
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PROJECT DETAILS |
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Start of survey:
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End
of survey: |
Team
size: |
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22.05
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28.08
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WEATHER
CONDITIONS
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| Season phenology: |
average
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Weather conditions: |
| Spring was average in timing with a very rapid transition in late May from cold period (-8-10øC) to warm period (+9-+12øC). Snow has melted during 11 days, and dissappeared by the start of breeding by most bird species. Extremal weather events were not observed. Negative temperatures at night were more common than usual during summer, which affected abundance and activity of insects. Wet and cold weather dominated during 10 days in the first half of August.
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| Date of 50%
snow-cover: |
4 June
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| Date of ice-break on
rivers: |
1 June
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| Date of final loss of
snow: |
8 June
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
average
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Breeding conditions:
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Arctic Fox numbers were average, and some young non-breeding animals were holding territories. Among 46 surveyed dens 45.7% were with broods. Fox density was 0.15 pair/sq.km in the permanent study plot (46 sq. km), and 57% of pairs bred. Average brood size was 8.67 (n=6) in August, which did not significantly differ from 2000 year value. Fox numbers were below average on the northern plain of the island, in the principal moulting site of Snow Geese.
Snowy Owl numbers were average, and density in the plot 0.2 nest/sq. km (in total 83 nests were found on the island). Average size of brood at fledging was 3.31 (n=16, range 0-5). Breeding success on the plot was slightly higher than in 2000.
Long-tailed Skuas and Common Eiders started egg-laying 10 days earlier than usual. Density of Long-tailed Skuas was 0.3 nest/sq.km (n=14). Reproduction was successful only in 14% of pairs, which is unusually low. About 30 Pomarine Skuas stayed in pairs in the plot in the first half of June, but in mid June they dissappered giving up breeding. Pomarine Skuas were practically never seen inland in July and August.
Predation pressure on birds was average or below average. Lemmings comprised 82% of diet of Snowy Owls, and birds - 18% (n=72), which is lower than in 2000. Remains of following birds were found in owl nests: wader chicks (3%), passerine chicks (7%), Common Eider adults and chicks (6%), Long-tailed Skua chicks (3%).
Nesting of Snow Geese in small colonies near nests of Snowy Owls was successful. In the island mountain areas geese nested near 56% of Snowy Owl nests (n=43), with exception of the Central Mountains where breeding geese were not seen. Average size of clutch of Snow Geese in small colonies was 3.99 (n=172). Deserted eggs were almost never found, and nest predation on the study plot was about 14% (n=400). Average size of brood of Snowy Geese was 3.48 after hatching (n=144) and 3.17 after fledging (n=24). Common Eiders did not form large colonies, but predation was low (8%) and average clutch size 5.95 (n=22). Only 2 nests of Brent Geese were found, and a single Canada Goose was seen in a small colony. Wader broods were regularly seen on excursions in August. Generally, breeding conditions were favourable for birds.
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Rodent dynamics:
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| Anticipated peak of lemming numbers did not occur, and their abundance was average. Rodent distribution was patchy, with areas of high and low density. Siberian Lemming dominated among rodents. Ventilation holes had a density of 8 per km at the start of snow melt (n=6 km), 2-3 tens of animals could be seen at a time during intensive melting, and density of winter nests was average - 6 per km (n=11 km). Average number of lemmings in Snowy Owl nest was 0.76 per one visit (n=78). According to all characters lemming numbers did not differ markedly from the previous season. High numbers and desntiy of young Siberian Lemmings were observed in Ushakovskoe settlement (71ø00'N, 178ø47'W) in the end of August.
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Rodent species recorded:
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Summary
of fauna studies: |
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