|
RESPONDENT
|
Vasili Baranyuk
|
|
SITE NAME
|
Tundrovaya River valley, Wrangel Island, Russia
|
|
| Contact
details (phone/fax//e-mail//address): |
| (095)441-12-16 // vvbar@vvbar.msk.ru // Lomonosovsky Pr., 35-40, Moscow, Russia |
|
PROJECT DETAILS
|
Project name:
|
|
Ecology of Snow Goose at Wrangel Island |
|
Start of survey:
|
End
of survey:
|
Team
size:
|
|
9.06 |
15.08 |
1 |
|
WEATHER CONDITIONS
|
|
|
|
Weather conditions: |
| Spring came with a delay of two weeks, and snow still covered 98% of surface at the start of the second week of June. The last three weeks of June were warm and dry. Snowfree patches reached 50% on 19 June and extended to the whole flat surface by 23 June. Cold weather returns with snowfalls catastrophic for birds were not recorded in the study period from 9 June to 15 August, with exception of light grainy snow on 26 July. Ice on the river broke on 13 June. The first half of July was mostly warm and dry, but windy, while second half of July and first five days of August were rainy with frequent fogs. After that weather became more dry, but winds were strong, reaching 25 m/s at blasts. |
|
|
|
|
|
| Date of 50%
snow-cover: |
19.06 |
|
| Date of ice-break
on rivers: |
13.06 |
|
| Date of final loss
of snow: |
23.06 |
|
BIOTIC CONDITIONS
|
| Rodents abundance evaluation: |
average |
|
Breeding conditions:
|
The total number of Arctic Foxes in the vicinity of Snow Geese colony was below average, but almost all territories were occupied by breeding foxes. Three dens that were surveyed in late July contained 7, 9 and 9 pups; 6 out of 9 pups in one of the dens were in good conditions, while other 3 - suffered from malnutrition. Nesting of Snowy Owls was late in general, and direct competition with Snow Geese for nest scrapes was recorded in two cases. Number of eggs in owl nests did not exceed 7, number of chicks before fledging varied from 1 to 3.
Breeding of Snow Geese in the main colony was complicated by pronounced deficiency of nesting area. Laying eggs in foreign nests and directly on the ground was common, as well as dump nests containing up to 52 eggs. Only about 10,400 pairs (1/4 of adults in the population) managed to settle in their nests at the main colony, and less than 2,000 pairs nested in small colonies associated with owl nests. 7,850 nests (75%) were successful at the main colony, that was left by approximately 25,000 of chicks. Yet about 5,000 chicks hatched in small colonies. These nesting results usually correspond to a fraction of juveniles on wintering grounds in November-December not exceeding 8-10%, however, in 1999 the fraction of juveniles was 14-16%. The fairy well result of the Snow Goose reproduction is uncommon in a sense that average reproductive performance was achieved after general failure of nesting. This became possible due to very high chick survival during brood-raring, promoted by favourable weather conditions, low Arctic Fox numbers and increasing lemming populations.
The increase in lemming populations and warm summer were also favourable for reproduction of other tundra birds. Late spring, probably, affected to a lesser extent nesting results of waders, passerines, some gull and skua species than of early breeders, like Snow Geese and Snowy Owls. |
|
|
Rodent dynamics:
|
| Lemming populations were increasing, and ratio of Siberian and Collared Lemmings was approximately 4:1 according to visual records and numbers of identified bodies near nests of Snowy Owls and dens of Arctic Foxes.
|
|
Rodent species recorded:
|
|
|
|
|
Summary
of fauna studies: |
|
|