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RESPONDENT
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Vladimir Pozdnyakov
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SITE NAME
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Lena Delta, southern and eastern parts, Yakutia, Russia
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| Contact details
(phone/fax//e-mail//address): |
| (411-2)33-68-15/(411-2)42-13-72(fax) // vpozd@mail.ru // Kulakovskogo St., 12-59, Yakutsk-7, 677077, Russia
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PROJECT DETAILS |
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Project name:
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Monitoring natural systems in the Lena River delta (birds)
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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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14.09
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4
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WEATHER
CONDITIONS
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| Season phenology: |
average
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Weather conditions: |
| Spring was average in timing. Air temperatures rose above freezing point from 31 May, and never dropped below it after 7 June at the south of the delta. Snowfalls were minor, and snow melted quickly afterwards. The snow completely melted at the flat surface by 11 June. Ice broke earlier than usual, and water table was average. Middle reaches of the Bykovskaya Channel (southeast delta) became ice-free on 8 June, mouth of the Bolshaya Trofomovskaya Channel (east delta) and mouth of the Bolshaya Tumatskaya Channel (north of delta) cleared on 10 and 11 June, respectively. Summer was warm and dry, and monthly mean temperatures exceeded the long-term average by 3.5øC in June, 1.8øC in July and 3.6øC in August. The last 10 days in June and July were particulary warm with mean temperature +13øC. Passage of a cyclone from 15-17 July was accompanied by rapid drop of air temperature, fitful wind and abundant precipitation, including snow spells. This period of inclement weather coinsided with hatching in waders and fledging in Snow Buntings.
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| Date of ice-break on
rivers: |
3-11.06
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| Date of final loss of
snow: |
11.06
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
low
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Breeding conditions:
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Arctic Foxes were regularly seen including young animals in the second half of July. Breeding of foxes was not observed in the coastal areas. Adult and young wolves were seen. Ermines were rare, but bred. Among skuas only Arctic Skua bred, while Long-tailed Skuas were observed in early July in wandering flocks measuring up 100 birds. Snowy Owls were very rare as solitary non-breeders. Rough-legged Buzzards were common, but nested in small numbers mostly in the southern parts of the delta, while numbers of breeding Peregrine Falcons did not change in comparison with 2000-2001. Remains of Brent Goose were found near one of the Peregine Falcons' nests. Broods of Raven were seen on the south of delta.
Weather conditions were favourable for birds. Numbers of Ross's and Sabine's gulls, Grey Plovers, Grey Phalaropes, Little and Temminck's stints and Ruffs increased compared with 2001 on the same islands. Nesting of Ringed Plover was observed on the north of delta. However, known colonies of Brent Geese decreased in size and became more dispersed, lacking cores of high nest density. Nesting density of Steller's Eiders did not exceed 0.7-1.0 pair/sq.km, locally reaching 2-3 pairs/sq.km. High density of King Eiders was observed only in colonies of Brent Geese and large gulls. A nest of Baikal Teal was destroyed by Arctic Fox in the presence of observers. Numbers of Willow Grouse and Rock Ptarmigan decreased compared with 2000 and 2001. Grey plovers nested at an average density 0.7-1.1 pair/sq.km. Grey Phalarope and Pectoral Sandpiper had relatively low densities approximating 10-11 pairs/sq.km and 3.5 pair/sq.km, respectively. Little Stint occurred in average numbers (8.2-8.8 pairs/sq.km), while high numbers were recorded in Temminck's Stint (12 pairs/sq.km) and Turnstone (6.5-7 pairs/sq.km).
Nesting success of birds was primarily affected by predation. Most nests of Steller's and King eiders, Long-tailed Duck and Pintail on the surveyed elevated islands were destroyed by Arctic Foxes, often before clutch completion. Nests of divers, Ross's and Sabine's gulls and waders were depredated there by Arctic Foxes, Arctic Skuas, Herring and Glaucous gulls. Low-profile seaside islands were free from Arctic Foxes, and bird clutches there suffered only from large gulls which resulted in high density of broods of Grey Phalaropes, Pectoral Sandpipers and Temminck's Stints. Nest success was above average (85%) in a Brent Geese colony, and average in Bewick's Swan, Herring and Glaucous gulls. Nest success was low in King Eider and Pintal, while Steller's Eider failed completely. Number of Bewick's Swan on a large island (40 by 20 km) in the central delta inhabited also by a family of wolves was considerably lower on 10 August compared with adjacent areas. Overall nest success of waders was low (on average 10-15%) in the delta. Main observations on density and nesting success of waders were carried out on the study plot about 7 sq.km at the east of delta. Nest success there was low in most species: 16.7% in Grey Plover (n=6), 15.4% in Grey Phalarope (n=12), 21.4% in Little Stint (n=28), 47.6% in Temminck's Stint (n=21), 78.6% in Turnstone (n=14) and 0 in Pectoral Sandpiper (n=3) and Ruff (n=2). Values for two latter species with small samples are likely conservative, as broods of Pectoral Sandpiper were observed later in the season. Nest success was low in Red-throated (33.3%, n=6) and Black-throated (40%, n=5) divers and in Ross's and Sabine's gulls. Better performance of Turnstones is, probably, due to their semi-colonial nesting and agressive nest defence by birds from several pairs in emergency.
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Rodent dynamics:
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| Low stage in lemming population continued for the second year, but juvenile animals appeared in the second half of summer. On the mainland in the southern part of delta stage of lemming cycle resembled that in 1999 preceding peak of numbers.
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Rodent species recorded:
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| Latin | Abundance |
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| Lemmus sibiricus | rare |
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Summary
of fauna studies: |
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