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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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5.06
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3.09
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WEATHER
CONDITIONS
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Weather conditions: |
| Snow melted completely by the time of start of nesting in most bird species. Summer was warm, and mean air temperatures ranged from +5.5-+9.9øC in the first half of June. Prolonged cooling in the second half of June and first week of July was associated with almost daily precipitation (mainly snow) and frost at nights, and variation of mean daily temperatures from -0.5-+4.8øC. Snowstorm on 22-23 June resulted in complete snow cover, but it melted already on 24 June. Positive temperatures prevailed at day-time during this cold period, and most bird species (geese, passerines, waders and owls) managed not to loose chicks, although chicks of Turnstones from two earliest broods had to feed in snow-covered tundra on 3 July. Mass movement of Snow Geese with broods to moulting grounds occurred during the period of adverse weather as well, but considerable decrease of brood size was not observed. Warm weather with mean day temperatures from +3.7-+17.7øC established by the time of mass hatching in waders and fledging in passerines. Weather was stable in August, when hot period gradually gave place to cool weather with positive day-time temperatures and frosts at night.
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| Date of 50%
snow-cover: |
23-24.05
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| Date of ice-break on
rivers: |
21.05
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| Date of final loss of
snow: |
30-31.05
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
high
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Breeding conditions:
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In the permanent study plot Arctic Foxes bred at a density 0.2 pairs/sq.km, Snowy Owls 0.27 nest/sq.km, Pomarine Skuas 0.29 nest/sq.km and Long-tailed Skuas 0.36 nest/sq.km. The plot was also inhabited by a single male of Short-eared Owl during the whole season, and was regularily visited by 2-4 Ravens which, however, were promptly moved away by all local skuas and owls. Waders and passerines were not found among prey of Arctic Foxes and owls. Diet of Snowy Owls comprised primarily from lemmings (94.8%, n=79), with female Common Eiders being negligible second (5.2%). Remains of juvenile geese were found near few dens of Arctic Foxes in geese moulting grounds in the Tundra of Academia. Arctic Foxes were common in all regions of the island and had average numbers. Among inspected dens 76.5% (n=51) contained broods. Snowy Owl numbers ranged from 0.025-0.4 nest/sq.km in different landscapes. Only 59% of owls bred (n=233), and 69 nests were found in total. Long-tailed Skuas had high numbers in all habitats suitable for breeding. Distribution of Pomarine Skua was extremely uneven. Apart of the plot in mountains this species was rare. Skua numbers were high on the northern plain, but only 49.6% (n=119) of birds bred. Reproductive success of skuas, owls and Arctic Foxes was high. Nest success of Pomarine Skua on the permanent plot was 84.6% (n=13), mean brood size was 1.55, and chicks started to fledge on 7 August. Chicks hatched in all nests of Long-tailed Skua (n=16), mean brood size 1.75. Arctic Foxes raised large broods (mean brood size 10.33, n=9). Snowy Owls clutch was 6.27 eggs on average (n=41), and mean size of brood at fledging was 5.07 (n=28, range 0-8).
Snow Geese successfully nested outside of the main colony near Snowy Owl nests. Geese colonies of at least 6 nests were found near 54.6% (n=27) nests of owls. About 400 pairs of geese bred on the plot. They started egg-laying already on 24-25 May, and broods started to move on 21 June. Mean clutch size was 4.41 (n=94), mean brood size after hatching 3.74 (n=156), and mean brood size at fledging in August was 3.67 (n=18). Predation of geese nests in colonies near owls was insignificant, and mass perdition from deseases was not observed.
Single nest of Brent Goose was found near owl nest, and this goose nest was successful. Common Eider nested in the inland areas of the island in high numbers, although large colonies were not found. Eiders started egg-laying before 10 June, and hatching occurred from early July to early August. Mean clutch size was 4.88 (n=17), and mean brood size after hatching was 4.83 (n=12).
Geese, waders and passerines started breeding earlier than normal. Mass fledging in Snow and Lapland buntings occurred in the end of June. Reproduction in waders was more prolonged than usual, their broods were numerous in July and August. Dunlins were less common than usual. Predation pressure was low, and reproduction of birds was successful.
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Rodent dynamics:
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| Numbers of Siberian Lemming were high, while Collared Lemming had average or low density in different areas. Undersnow nests of lemmings occurred at a density of 19 /km. Peak lemming numbers can be reached in 2003, if Siberian Lemmings retain their density and Collared Lemmings further increase in numbers.
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Rodent species recorded:
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| Latin | Abundance |
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| Lemmus sibiricus | abundant |
| Dicrostonyx torquatus | common |
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Summary
of fauna studies: |
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