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RESPONDENT
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Hans Schekkerman
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SITE NAME
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Medusa Bay, Taimyr Peninsula, Russia
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| Contact
details (phone/fax//e-mail//address): |
| +31-222-369766/+31 222319235 // h.schekkerman@nioo.knaw.nl // Alterra P.O.Box 167, 1790 AD Den Burg, The Netherlands |
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PROJECT DETAILS
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Project name:
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Breeding birds at Medusa Bay, N.W. Taimyr |
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Start of survey:
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End
of survey:
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Team
size:
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8.06 |
12.08 |
10 |
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WEATHER CONDITIONS
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Weather conditions: |
| Snow cover was nearly complete upon our arrival and snow melt occurred 1-2 weeks later than in the two previous years, with 50% snow cover and flowing of major streams on 20 June. Rapid snow melt was started not by high temperatures, but by heavy rain. The summer of 2002 was on average a bit colder that that of 2001, though not as cold as 2000. Apart from a colder start (average June temperature in 2000 1.2øC, 2001 4.0 øC, and 2002 2.0 øC), the general pattern in air temperature was similar to that in 2001, although peak temperatures were reached a few days later. However, 2002 was distinctly less sunny. The most remarkable feature of summer 2002 was its wetness: between 6 June and 9 August no less than 132 mm of precipitation was recorded, compared to 59 mm in 2001 and 7 mm in 2000. Nearly all of this fell in the form of rain; the only significant snowfall occurred on 6 July, but the tundra stayed white for a few hours only. Both the number of days with rain and the amount of rain falling on rainy days were larger than in previous years. |
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| Date of 50%
snow-cover: |
20.06 |
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| Date of ice-break
on rivers: |
21.06 |
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| Date of final loss
of snow: |
26.06 |
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BIOTIC CONDITIONS
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| Rodents abundance evaluation: |
average |
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Breeding conditions:
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Pomarine Skuas (c. 2 pairs/km2), Rough-Legged Buzzards - 20 active nests (15 of them contained eggs, 1 deserted, 2 destroyed, other hatched and, probably fledged) in 275 km2, and Snowy Owls (3 nests in c. 30 km2, 9 nests in 275 km2) bred (though clutches were small, 4-6 eggs), but suffered lack of food later in the season; all snowy owl young died. Foxes were scarce but some reproduced. Geese and ducks bred in larger numbers than in the two previous years, with several Brent Goose colonies around Snowy Owl nests (64 nests in 4 colonies and 2 single nests near owls), as well as scattered solitary pairs (21 nests). Brent Goose: a total of 85 nests in the inland tundra (searching area - 275 km2), plus 35 nest on the offshore islands.
Wader arrival was retarded due to cold weather and persisting snow cover, with flocks of further northbound species (Knot, Purple Sandpiper, Dunlin) staging in the few snow-free patches for a few days. Nesting commenced 7-10 days later than in 2000 and 2001, around 20-25 June in the early species, and 2-5 days after the sites had become exposed. Laying periods were markedly compressed, with 50% of clutches completed within 3 days in Dunlin, and within 5 days even in Little Stint. Despite the late spring, breeding numbers of most wader species were similar to the previous years, with lower numbers only in Pacific Golden Plover and Curlew Sandpiper. Surprisingly, the influx of breeding Pectoral Sandpiper and Red Phalarope in the warm spring of 2001 was repeated in 2002, though Pectorals were less numerous this year (2 nests).
Nest success varied between bird groups: probability of surviving the nesting period was 65% for passerines, 59% for waders (21-73% depending on species), 61% for skuas. White-fronted Geese were quite successful - 8 of 9 found nests hatched (89% hatching success). In inland Brent Geese nests 25 of total 85 hatched (29.4%). On islands no Brent predation recorded at all, probably most of clutches hatched and fledged. In spite of presence at least 12 prospecting Red-breasted Goose pairs, probably, only 1 nest was initiated and 1 brood hatched. Large bird eggs seemed to be especially sought after by foxes, while small eggs were taken more occasionally by both skuas and foxes. Even some Brent Goose colonies near Snowy Owls were raided by foxes, perhaps because none of the owls was very aggressive towards (human) intruders. Predation of wader eggs started when lemming abundance on the tundra surface dropped as summer burrows thawed out, in early July. Hatching of wader chicks coincided with several days of warm weather and high insect abundance, but throughout much of the prefledging period sunshine was scarce and insect numbers low. Chicks showed somewhat retarded growth but many did survive to fledging. Our eventual impression was of moderate breeding success for waders, low (Red-breasted Goose) success for geese and low success for raptorial birds. |
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Rodent dynamics:
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| After two years of very low abundance, lemming numbers had increased (season average 1.4 animals seen /10 h in field) but not reached a real peak. None were seen until 15.06, but shortly after the snow melt, lemmings seemed abundant (between 20.06 and 30.06 up to 10 lemmings seen /10h), but this declined rapidly as they moved into summer burrows and/or were taken by predators, to less than 1 seen /10h after 5.07. Overall season lemming density - 10-12 individuals / hectare, from live-trap censuses. Siberian Lemmings were 10 times more abundant than Collared.
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Rodent species recorded:
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| Latin | Abundance |
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| Lemmus sibiricus | common |
| Dicrostonyx torquatus | rare |
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Summary
of fauna studies: |
Daily records of weather data included ir temperature, operative (black sphere) temperature, wind speeds and direction (all near-continuous), rainfall in mm.
The following studies were conducted:
Arrival phenology and arrival condition of shorebirds (clap-netting);
Return rates, including arrival date, of colour-marked Dunlin and Pacific Golden Plover;
Territory mapping of all breeding waders in 4km2 plot and selection of species in 12km2;
Mapping of breeding raptors, owls and geese in approx. 30km2 and 275 km2;
Breeding phenology, clutch and egg size, and nest success in waders and other birds;
Trapping and ringing of adult waders during incubation and chick-rearing;
Growth and energetics of waders chicks (Little Stint; doubly-labelled water measurements of energy expenditure in chicks, time budgets of broods, growth rates of chicks);
Daily sampling of surface arthropod activity in pitfall traps;
Nest isolation and egg cooling/heating in intermittently incubating waders;
Energy expenditure of incubating and chick-rearing adult Dunlin;
Nest attendance of incubating Little Stint in relation to supplemental feeding;
Condition of waders leaving Taimyr on autumn migration.
Studies to be summarised in Alterra-report, spring 2003, and in several papers. |
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