192
Land-Ocean Systems in the Siberian Arctic: Dvnamics and HistoQ'
So the total value of migration PEMG is:
PE MG (KJ) = 154 - (PE mg . L, + PE mg ' L z )
(5)
where L, is distance of migration from the Chukchi Sea Polynya to the Laptev Sea Polynya,
Lz is distance of migration above Laptev Sea Polynya, coefficient 1.54 shows the efficiency of
lipogenesis. Females deposit into clutch was calculated according to the equation of Dolnik
(1995):
PEel (KJ) = 32.49mf06Z6
(6)
Impact on the bottom fauna
Five stomachs of King Eiders from the Polynya provide the data on diet. Caloric density of
main food (Gastropoda and Bivalvia) is 17.8 KJ/g, metabolic efficiency coefficient is 0.81,
ratio between dry and wet weight is 0.25 in molluscs (Kendeigh et a!., 1977), while the shell
accounts for 30% of the wet weight (Alimov, 1981). Dive duration in King Eider of 91 seconds
was used (Systad, 1996).
Results
Aerial surveys and observation of migration
We found four marine birds occurring on the Polynya in significant numbers (Table 1), as
follows: King Eider, Long-tail Duck (Clangula hyemalis), Kittiwake (Rissa tridactyla), and
Pomarine Skua (Stercorarius pomarinus). One more species - the Snow Bunting
(Plectrophenax nivalis) - was registered once.
Intensive westward migration passed on 25 and 29 of May (Table 1). Ducks migrated in large
flocks sometimes up to 300 individuals in King Eider, some flocks flew across drift ice fields
from one lead to another. Kittiwakes and Pomarine Skuas migrated individually or in loose
flocks up to 6, their flight passed above leads, following its configurations. The most intensive
migration was observed from fast ice edge (74 24 'N 129 29'E) on 25 of May when we counted
2627 King Eiders in 68 minutes.
Bioenergetics
Body mass and basal metabolic rate (BMR)
Mean body mass in King Eider males was 1790 (SD, 184)g, in females 1700 (SD, 209)g.
Basal metabolic rate in winter was 607.7KJ/day and 584.5KJ/day accordingly.
Thermoregulation
Thermoregulation, calculated for non-diving and non-flying time of day (Table 3), was
estimated at 0.23 BMR for males and 0.24 BMR for females.
Daily time budget
Winter DTB of King Eider's maintenance (Systad, 1996), transformed according to equations
(2, 3)for polar day and added by extra feeding to cover productive needs, is shown in Table 3.
We also add sleeping and flying activities. Summarising values of each EA we get the total
energy of activity as 2.24 BMR for males and 2.32 BMR for females.
Land-Ocean Systems in the Siberian Arctic: Dvnamics and HistoQ'
So the total value of migration PEMG is:
PE MG (KJ) = 154 - (PE mg . L, + PE mg ' L z )
(5)
where L, is distance of migration from the Chukchi Sea Polynya to the Laptev Sea Polynya,
Lz is distance of migration above Laptev Sea Polynya, coefficient 1.54 shows the efficiency of
lipogenesis. Females deposit into clutch was calculated according to the equation of Dolnik
(1995):
PEel (KJ) = 32.49mf06Z6
(6)
Impact on the bottom fauna
Five stomachs of King Eiders from the Polynya provide the data on diet. Caloric density of
main food (Gastropoda and Bivalvia) is 17.8 KJ/g, metabolic efficiency coefficient is 0.81,
ratio between dry and wet weight is 0.25 in molluscs (Kendeigh et a!., 1977), while the shell
accounts for 30% of the wet weight (Alimov, 1981). Dive duration in King Eider of 91 seconds
was used (Systad, 1996).
Results
Aerial surveys and observation of migration
We found four marine birds occurring on the Polynya in significant numbers (Table 1), as
follows: King Eider, Long-tail Duck (Clangula hyemalis), Kittiwake (Rissa tridactyla), and
Pomarine Skua (Stercorarius pomarinus). One more species - the Snow Bunting
(Plectrophenax nivalis) - was registered once.
Intensive westward migration passed on 25 and 29 of May (Table 1). Ducks migrated in large
flocks sometimes up to 300 individuals in King Eider, some flocks flew across drift ice fields
from one lead to another. Kittiwakes and Pomarine Skuas migrated individually or in loose
flocks up to 6, their flight passed above leads, following its configurations. The most intensive
migration was observed from fast ice edge (74 24 'N 129 29'E) on 25 of May when we counted
2627 King Eiders in 68 minutes.
Bioenergetics
Body mass and basal metabolic rate (BMR)
Mean body mass in King Eider males was 1790 (SD, 184)g, in females 1700 (SD, 209)g.
Basal metabolic rate in winter was 607.7KJ/day and 584.5KJ/day accordingly.
Thermoregulation
Thermoregulation, calculated for non-diving and non-flying time of day (Table 3), was
estimated at 0.23 BMR for males and 0.24 BMR for females.
Daily time budget
Winter DTB of King Eider's maintenance (Systad, 1996), transformed according to equations
(2, 3)for polar day and added by extra feeding to cover productive needs, is shown in Table 3.
We also add sleeping and flying activities. Summarising values of each EA we get the total
energy of activity as 2.24 BMR for males and 2.32 BMR for females.