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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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Waterfowl monitoring in the Lena River delta
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Start of survey:
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End
of survey: |
Team
size: |
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30.05
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27.08
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2
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WEATHER
CONDITIONS
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Weather conditions: |
| Spring was early, but developed slowly. Mean day air temperatures were positive on 11-12, 25-26 and 30-31 May, but dropped below freezing on 2-3, 6 and 18 June. Small amount of snow was accumulated during winter, and snow cover melted completely by 30 May. Rivers broke slightly later than normal, and cleared only in 12-14 days because small amount of melt water was not able to break ice-jams. Bykovskaya channel in the middle reaches (SE part of delta) cleared on 20 June, and Trofimovskaya channel (east of delta) cleared on 24 June. Mean monthly air temperatures were 2.9øC, 1øC and 2øC above average in May, June and July respectively, but the first 20 days of June were cold and wet with rain or snow occurring almost daily. Snow cover reached 5-10 cm during night, but melted during day.The last 10 days of June and the period from 10-20 July were particularly warm, and temperatures reached +13.8 and +14øC, respectively.
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| Date of ice-break on
rivers: |
9-24.06
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| Date of final loss of
snow: |
30.05
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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 and wolves were not seen, but signs of predation by foxes were found in colonies and on isolated nests of waterfowl. Ermines were rare, and their breeding was not confirmed. Brown Bear was seen on the delta south in mid August. Skuas (primarily Pomarine Skua) were seen in high numbers only on spring migration. Their summer numbers were below average and nesting was not recorded. Snowy Owls was seen once on 10 July. Rough-legged Buzzards bred in the southern part of delta at a low density, typical for low lemming years. Numbers of breeding Peregrine Falcons was similar to previous years. A brood of Ravens and two juvenile Kestrels were seen on 17 August in the middle reaches of the Bykovskaya channel at the southeast of delta, while solitary Kestrel and 2 Gyrfalcons were seen on 22 and 26 August, respectively, in the channel mouth.
Effects of weather on breeding performance differed among species. Early snow melt was likely favourable for nesting of Brent Geese and Steller's Eiders in high numbers. We counted approximately 400 pairs of Brent Geese in 5 colonies in the mouth of the Bolshaya Trofimovskaya channel, including 220 pairs in the largest colony. Steller's Eiders nested at a density 5-14 pairs/km2. Relatively cold first half of June led to decreased breeding numbers of Ross's Gulls, while Sabine's Gulls nested in usual numbers. Nesting density of Grey Plover, Little and Temminck's stints and Turnstone was lower than in 2002, but Grey Phalaropes, Ringed Plovers, Curlew and Pectoral sandpipers and Ruffs nested in similar to 2002 numbers.
Predation pressure on bird clutches was considerably lower than in 2002, although locally many clutches could have been destroyed. Nest predation was 66.7-75% in colonies of Brent Geese visited by Arctic Foxes, while large gulls destroyed only 5-11.8%. Combined nest success of Brent Geese in the north-east of delta was 84.2%. Two colonies (5 and 14 pairs) of Steller's Eiders were destroyed by foxes, but chicks hatched in 88% of nests on the control island, which was not visited by foxes. Also foxes destroyed 1 from 2 nests of Bewick's Swans and 2 from 21 nest of King Eiders, and presumably partially removed eggs from 1 from 4 nests of White-fronted Geese, because cashed egg was found in moss near nest of geese with a clutch of 3. Wandering Pomarine and Arctic skuas were the most active among avian predators. Remains of a Ringed Plover, egg-shells of ducks, ptarmigans and waders were found in stomachs of Pomarine Skua. Nest predation was 33% in Black-throated Diver (n=3), 12% in Steller's Eider (n=25), 25% in Grey Plover (n=4), 40% in Turnstone (n=5), 25% in Grey Phalarope (n=4), 40% in Little Stint (n=10), 100% in Curlew Sandpiper (n=2), and 80% in Ross's Gull (n=5). Apparent nest success in waders was 68.75% (n=32). Nest predation was not recorded in Red-throated Diver, Pintail, Long-tailed Duck, Ringed Plover, Temminck's Stint, Pectoral Sandpiper, Sabine's Gull and Arctic Tern. Broods of Pacific Golden Plover and Dunlin were found at the southeast of the delta in mid July, and a male Red-necked Phalarope was seen which behaviour suggested presence of chicks. Generally, breeding success can be evaluated as average to high in most birds.
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Rodent dynamics:
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| Lemming numbers decreased compared to the autumn 2002 due to low amount of snow in the winter. Undersnow nests were found only in the banks of snow near prominent relief features and mostly in human settlements. Active breeding and increase of numbers during summer were not observed.
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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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