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Yury Andryushchenko, AZBOS

Monitoring of wintering birds communities was started from late November 2010 to early March 2011 (11 surveys), and after testing and making corrections in the work scheme it was repeated from late November 2011 to early March 2012. In the first winter period there were 11 field trips each decade and 8 fieldtrips in the second period.

The structure of bird communities was estimated according to dynamics of species composition, ratio of quantity of birds and number of species in two types of control plots located in zonal (dry steppe zone of the Azov area) and intrazonal ecosystems (Syvash) (fig.1). The responses of bird communities to ice and snow cover were traced. Coverage of ground with snow and water bodies with ice was estimated in %.

 

Fig. 1. Location of control plots within dry steppe zone of Ukraine

Borders of dry steppe subzone – blue dashed line

Control zonal lands – squares and wetlands – color fill:

  • red – investigated regularly;
  • yellow – investigated in early winter;
  • green – in the second half of winter

 

Monitoring results of winter 2010/2011.

Condition of snow and ice cover is shown in fig.2. The winter 2010/2011 was characterized with little snow, but rather long-term ice cover formed only in the end of January but remained until the first decade of March inclusively. The condition of snow cover substantially differed for the intrazonal lands in Syvash (Sivash) region and the zonal lands located further to the north (fig. 4).

The monitoring allowed to identify quantitative dependence of a structure of wintering groupring of birds from snow and ice cover. The discovered trend of the state of wintering bird species community, their species structure and number dynamics can be used as an indicator of climate trends.

Fig. 2. Dynamics of changes of mean indices of snow and ice cover in the investigated area during winter 2010/2011

 

Fig.3. White-tailed near a glade on a control plot in late February 2011 (moderately saline Eastern Syvash)

 

The number trends in figures 5 and 6 show that, judging by trends of bird numbers, the response was similar even for the species with different ecological requirements. However, bird communities wintering in intrazonal and zonal lands should be analyzed separately due to their distinct species composition.

A

B

Fig. 4. Differences in the condition of snow and ice cover in wetland (A) and zonal (B) areas during winter 2010/2011.

Fig. 5. Changes in numbers of some mass bird species in winter 2010/2011.

Fig. 6. Number dynamics of bird species with different ecological requirements: the mute swan, great bustard, shelduck.


 

A total of 409,079 individuals were recorded during winter monitoring 2010/2011. Of them the species was identified for 332,398 ind. (90 species) (Table 1).

The most numerous were the species which during daylight chiefly stay in open biotopes (agricultural fields, parts of water bodies without above-water vegetation, etc.).

Table 1:  Species composition and numbers of birds counted during winter 2010/2011

Species

Number

 

Species

Number

1

Tachibabtus ruficollis

12

 

48

Numenius arquata

46

2

Podiceps cristatus

609

 

49

Larus ichthyaetus

30

3

Phalacrocorax carbo

331

 

50

Larus melanocephalus

143

4

Egretta alba

27

 

51

Larus ridibundus

489

5

Ardea cinerea

22

 

52

Larus genei

38

6

Rufibrenta ruficollis

48,932

 

53

Larus cachinnans

6,940

7

Anser anser

44

 

54

Larus canus

3,813

8

Anser albifrons

33,098

 

55

Columba palumbus

2

9

Cygnus olor

1,053

 

56

Columba oenas

5

10

Cygnus cygnus

25

 

57

Streptopelia decaocto

1,126

11

Tadorna ferruginea

3,338

 

58

Asio otus

6

12

Tadorna tadorna

8,021

 

59

Asio flammeus

22

13

Anas platyrhynchos

28,941

 

60

Athene noctua

1

14

Anas crecca

112

 

61

Dendrocopos syriacus

13

15

Anas strepera

1

 

62

Galerida cristata

800

16

Anas penelope

484

 

63

Calandrella rufescens

45

17

Anas acuta

417

 

64

Melanocorypha calandra

23,752

18

Anas clypeata

807

 

65

Alauda arvensis

262

19

Aythya ferina

128

 

66

Anthus pratensis

156

20

Aythya fuligula

322

 

67

Sturnus vulgaris

82,296

21

Aythya marila

27

 

68

Pica pica

1,631

22

Bucephala clangula

500

 

69

Corvus monedula

1,022

23

Circus cyaneus

263

 

70

Corvus frugilegus

7,783

24

Circus aeruginosus

18

 

71

Corvus cornix

1,618

25

Accipiter gentilis

8

 

72

Corvus corax

690

26

Accipiter nisus

18

 

73

Troglodytes troglodytes

3

27

Buteo lаgopus

273

 

74

Turdus pilaris

1,363

28

Buteo rufinus

36

 

75

Turdus merula

2

29

Buteo buteo

41

 

76

Panurus biarmicus

45

30

Aquila chrysaetos

1

 

77

Parus caeruleus

17

31

Haliaeetus albicilla

130

 

78

Parus major

26

32

Falco cherrug

12

 

79

Passer domesticus

702

33

Falco columbarius

14

 

80

Passer montanus

494

34

Falco tinnunculus

84

 

81

Fringilla coelebs

2,432

35

Perdix perdix

147

 

82

Fringilla montifringilla

56

36

Grus grus

540

 

83

Chloris chloris

250

37

Rallus aquaticus

2

 

84

Spinus spinus

14

38

Gallinula chloropus

18

 

85

Carduelis carduelis

2,519

39

Fulica atra

44,423

 

86

Acanthis cannabina

5,520

40

Otis tarda

1119

 

87

Coccothraustes coccothraustes

43

41

Eudromias morinellus

30

 

88

Emberiza calandra

4,670

42

Vanellus vanellus

1

 

89

Emberiza citrinella

459

43

Recurvirostra avosetta

21

 

90

Emberiza schoeniclus

385

44

Tringa ochropus

6

 

 Species

90

45

Philomachus pugnax

1

 

Ind. 

 

Identified as species

332,398

46

Calidris alpina

60

 

47

Gallinago gallinago

2

 

Total

409,079

 

In zonal lands, the numbers of birds had been smoothly decreasing until mid January until formation of continuous snow cover to the north of the investigated area (fig. 7). At the same time on the control plot circa 90% of ground was covered with snow only 3-8 cm deep. Snow-melting in early February in the investigated area favoured increase of bird numbers while the movement of melting zone to the north invoked the numbers decline.

 

Fig. 7. Ratio of the surface area of snow cover between 25.12.2010 and 05.01.2011

 

In intrazonal lands, birds chiefly feeding in shallows (mainly Ciconiiformes and waders) are the first to leave the area after formation of ice cover. The reaction to ice cover is weak-pronounced in birds which feed on ground, but rest on water. Most typical winter representatives of them in the region are, first of all, geese and gulls.

Summarizing the outputs of the fulfilled analysis, we can conclude that among waterbirds the most optimal indicators of ice cover are Cygnus olor, Tadorna tadorna, Anas clypeata, Anas acuta, Anas crecca, Aythya fuligula, Larus ridibundus, Fulica atra, which react differently on the ice cover condition.

When ice cover is formed the following response is observed among numerous regularly wintering waterbird species:

  • Anas clypeata, Anas acuta, Aythya fuligula are the first to leave the area;
  •  after them - Larus ridibundus, and the last to roam away are Cygnus olor, Fulica atra, Tadorna tadorna;
  •  geese, the Yellow-legged Gull and the Common Gull, feeding predominantly on ground, almost do not leave the area or do not leave it at all, and that is why their numbers and distribution on wintering grounds depend on surface area and depth of snow cover.

Monitoring results of winter 2011/2012.

Basing on experience of the previous season, the count routes were chiefly made in sub-meridional direction since snow cover in the region changes north to south. Condition of snow and ice cover is shown in fig. 8. However, in the winter 2011/2012 there was no significant difference in snow and ice cover between wetlands and more northern zonal lands.

During winter monitoring 2011/2012, a total of 120,817 individuals were counted. Among them the species was identified for 105,904 individuals (82 species).

A contrasting, in terms of climate conditions, winter 2011/2012 allowed to track the response of wintering bird community in the region: until 20th dates of January – complete absence of snow and ice cover with positive temperatures. After a sharp fall of temperature in late January in the investigated region and formation of almost continuous ice cover, most waterbird species left this area.

Formation of almost continuous (over 40% of the territory in Syvash and about 90% in the near-Syvash area) and relatively deep (averagely, over 20 cm in Syvash and about 20 cm in the near-Syvash area) snow cover in late January induced the decline in bird numbers in both types of lands.

Though only monitoring of the community of all wintering birds will reflect supposed climate changes the most completely, we can anyway distinguish the most demonstrative species to show the dependence on snow and ice cover. Analysis of the investigation results revealed more than 20 species for which the accessibility of forage depends on the depth and surface area of snow cover (about 13 species), and on surface area of ice cover –(10 species) (Table 2).

Fig.8. Dynamics of changes in mean indices of condition of snow and ice cover in the investigated area during winter 2011/2012.

 

Table 2. Control bird species the most obviously demonstrating the dependence on condition of snow and ice cover in dry steppe subzone of Ukraine (according to count results 25.11.2010-07.03.2011)

Species

Feeding (mainly) in biotopes:

Dominant type of feeding in winter

terrestrial *

water

1

Podiceps cristatus

 

1

ichthyophagist

2

Phalacrocorax carbo

 

1

ichthyophagist

3

Rufibrenta ruficollis

1

 

phytophagous

4

Anser anser

1

 

phytophagous

5

Anser albifrons

1

 

phytophagous

6

Cygnus olor

 

1

phytophagous

7

Cygnus cygnus

1

 

phytophagous

8

Tadorna ferruginea

1

 

phytophagous

9

Tadorna tadorna

 

1

hydrobionts

10

Anas platyrhynchos

 

1

phytophagous

11

Aythya ferina

 

1

phytophagous

12

Aythya fuligula

 

1

hydrobionts

13

Circus cyaneus

1

 

bird of prey

14

Buteo lаgopus

1

 

bird of prey

15

Buteo rufinus

1

 

bird of prey

16

Buteo buteo

1

 

bird of prey

17

Falco tinnunculus

1

 

bird of prey

18

Otis tarda

1

 

phytophagous

19

Fulica atra

 

1

phytophagous

20

Larus cachinnans

 

1

omnivorous

21

Larus canus

 

1

omnivorous

22

Melanocorypha calandra

1

 

phytophagous

23

Sturnus vulgaris

1

 

phytophagous

 

Total

13

10

 

* species gathering forage on ground, birds of prey –in flight or seizing from ground or grassy vegetation, waterbirds are indicated in dark colour-filled lines

 

The diurnal birds of prey were indicative for the assessment of the numbers of birds in zonal biotopes, especially myophages: the Hen Harrier, Rough-legged Buzzard, Long-legged Buzzard, Common Buzzard, Imperial Eagle, Kestrel. In little-snow winters in northern regions, they almost do not reach the dry steppe zone of Ukraine and appear there after the formation of continuous deep snow cover. They can be used as reliable indicator of condition of snow cover on large territories.

Number of ornithophagous birds (the Sparrowhawk, Goshawk, Marsh Harrier, Saker Falcon, Peregrine Falcon, Merlin) is not too dependent on the nature of the winter: annually they form a stable wintering core in the region.

Thus, with a general warming of winter temperatures a majority of birds can winter to the north of the Azov-Black Sea region not forming large concentrations in the region. Zonal and intrazonal lands of the region play a buffer role for wintering bird communities during cold snaps in Eastern Europe, and in case of sharp fall of temperature in the south Ukraine mass wintering grounds of most birds move south and south-west. In this situation the Azov-Black Sea region of Ukraine loses its importance as wintering grounds, especially for waterbirds. Trends of increasing frequency of warm winter will promote growth of significance of the region for the formation of relatively stable wintering bird complex.