Establishing of new breeding groups of the White-tailed Eagle after constructing of water reservoirs

The territory of the Volga-Kama region (about 525 thousand square kilometers)

The territory of the main Directions of research: research conducted in the • nesting monitoring; • study of abundance and spatial last 7 years • • •

distribution; study of biology and ecology of reproduction; the study of territorial links by means of a ringing program; wintering study.

In the course of the research, certain regularities in the formation of nesting groups have been revealed, which make it possible to predict their subsequent development

• From literature it is known that in the XIX and early XX centuries the WTE was an ordinary species in the VolgaKama region.

• The history of the dynamics of the population number of the WTE in the Volga-Kama region in the XX century does not have exact data. There is also no data on the effects of DDT(DDE) and other factors.

• The most reliable factor that could influence the population number of the WTE is anthropogenic transformation of river Volga and river Kama valleys

The anthropogenic transformation of the valleys of the Volga and Kama, during the creation of reservoirs in the XX century, led to a change in the landscapes suitable for nesting

The site of the Volga-Kama floodplain in the estuary of the Kama before the creation of the Kuibyshev Reservoir (1950)

• "In the flood plain of the Kama river, white-tailed eagles are quite numerous" (Zharkov, Teplov, 1932)

"Scenario" of the formation of new nesting groups • Distribution of the species from the remaining foci of nesting groupings in Prikamye, Pribel'e, in the Samara region and in the Volga-Kama Reserve.

• Initial development of coastal forests with good protective conditions on the coastal slopes and terraces.

• Subsequent nesting on more open biotopes of the islands of reservoirs, with the formation of semi-colonial groups.

• Settlement beyond the boundaries of large reservoirs.

The population number and spatial distribution of the WTE at the end of the XX century during the middle stages of restoration

Distribution of nests in the lower reaches of the Kama River at the end of the XX century The white-tailed eagle originally settled on sites with the best protective conditions in the forested areas on the coastal slopes and river terraces

Probable directions of settling of the WTE in the XX century.

• Return of the rings from the central part of the VolgaKama region. Current research data.

The influx of immigrants is also taking place at present

• Within the reservoirs in the territory of Tatarstan there are up to 60-80 young birds in the nesting period. Are they local birds or immigrants?

Expected philopatria in 2016 - 22.86 - 25.74%; real - 2.22%

• Number of ringed eaglets in the Republic of Tatarstan from 2012 to 2015. - 139 individuals (22,86 – 25,74%; n=540-608) • 1 ringed bird (2.22%) out of 45 young, who managed to inspect their paws in 2016.

Modern data on the population number and distribution of WTE (500-600 pairs)

There was a semi-colonial structure of nesting sites on the islands of the Kuibyshev reservoir

0,49 km

Upper Kuibyshev Reservoir • In the forests on the coastal slopes, the population numbers for the last 20 years have not changed. • There was an increase in the population number of islands.

Spatial distribution of nesting sites in the area of the Nizhnekamsk reservoir The end of the XX century

Modern data

Nizhnekamsk Reservoir

•

There was an increase in numbers on the islands and in the floodplain.

The distribution of the WTE was promoted by the gray heron (Ardea cinerea ) colonies

Common features in the formation of breeding groups of the WTE at the reservoirs

• Formation of semi-colonial structure depending on landscapes and feed conditions.

• Neglect of the protective conditions of nesting areas, • Shortening the distance between nesting pairs; • Possible resettlement beyond the reservoirs

Minimum distances between nesting pairs in dense groupings of the Kuibyshev Reservoir

There are no islands on the Votkinsk Reservoir, so the semi-colonial structure was not formed. But since the beginning of the XXI century, practically no one has conducted research.

Probably there should be an increase in the number of the WTE at the Cheboksary reservoir, where the colonial structure of nesting sites on the islands is also possible

Probably the special feeding conditions of the reservoirs contributed to a sharp increase in the number of WTE

Within the reservoirs, an increase in the proportion of fish and a decrease in the proportion of mammals and birds in the diet of WTE 31% (Zharkov, Teplov, 1932); 25–27% (Karyakin, 1998); 96,7% (Ayupov et al., 2016).

• At the beginning of the 20th century it was believed that the eagles were able to feed only 1 chick Zharkov, Teplov, 1932). • The practice of modern research shows the successful feeding of even 3 chicks.

Year

Average number chicks in nests older than 30 days

2012

1,69±0,7; n=16; Ex=-0,64

2013

1,78±0,64; n=27; Ex=-0,49

2014

1,81±0,7; n=31; Ex=-0,86

2015

1,87±0,72; n=31; Ex=-0,95

2016

1,74±0,49; n=34; Ex=0,29 1,78

??? • Under the big question, the stability of new breeding groups and the further increase in the number of nesting pairs within their limits

Settling to the new habitats other than surroundings of water reservoirs is a good indicator of the species status and dynamics • Less than 10% of all breeding sites are located on plains of small rivers, agricultural landscapes and trash damps. • Despite positive expectation towards overall breeding trends in Volgo-Kama region, on some territories population growth has stopped. Like in Saratov region (Moseikin,2008 ) and Tatarstan Republic where White-tailed Eagles are not breed in agricultural landscapes anymore.

Nesting data of WTE in the central part of the Volga-Kama region Year

Checked nesting sites

Sites with nests

Busy Active nesting nesting sites sites

Successful sites

Number

% from Active

% from Busy

% from all

2012

39

35

31

25

16

64%; n=25 51,61%; n=31

45,71%; n=35

2013

56

56

54

34

27

79,41%; n=34

50%; n=54

48,21%; n=56

2014

73

73

63

42

31

73,81%; n=42

49,2%; n=63

42,46%; n=73

2015

79

79

66

48

31

64,58%; n=48

46,97%; n=66

39,24%; n=79

2016

82

81

70

61

41

67,21%; n=61

58,57%; n=70

50,62%; n=81

69,8%

51,27%

45,25%

The annual increment of population number for WTE in central part of Volga-Kama region • We expect 51.27% breeding success in population under study that makes 76.39 – 85.62 successfully breeding pairs out of total 149-167 pairs. The annual population increment is 135.97 – 152.4 individuals.

• The birthrate calculated for breeding (adult) birds only is 0.45 individuals per 1 bird.

• The birthrate calculated for all population including 80100 non-breeding (subadult) individuals is 0.35-0.37 ind/ind.

Continuous successful breeding for 3-5 consecutive years occurred only in 14 nests (12,06%; n=116)

Nest sites with a long absence of reproduction (2-5 years) accounted for more than 36%

The death of adult birds is the main reason for the long absence of breeding in the nesting sites

The death on the power line continues.

What is the proportion of mortality - we do not know what prevents us from getting a full picture of the effect of this factor on the population.

Breeding interruptions for active nests averaged 30.2%

Since only three cases of unfertilized eggs were observed we cannot make a clear conclusion about the effect of chemical pollution of water on breeding success.

Reasons for the interruption of reproduction 1. Partly it is forest fires and destruction of nests; 2. Anxiety of birds by a man during the incubation of a masonry

3. Early reproduction times may also cause interruption of reproduction

• In the first half of the XX century, the beginning of breeding occurred in the second half of March (Zharkov, Teplov, 1932)

There was a shift to earlier breeding times

Establishing of new anthropogenic wintering sites that gather large number of White-tailed Eagles is the main reason for alterations in breeding terms and possibly a reason for population number increase in XXI. • •

On local sites, up to 500 individuals can be found at a time

The total number of White-tailed Eagle in the region during the winter period could reach 1000-1500 individuals.

Photo: M. Timofeev •

Places of concentration: places of emissions of meat products near poultry farms and pig farms, landfills of solid domestic waste, open areas of reservoirs

Changing the conditions of anthropogenic wintering and tightening control over the discharge of waste from poultry farms and livestock complexes can lead to changes of population number and biology of the species

•

Between 1997 and 2017, disappeared 3 large winter concentrations in the Samara region, after the cessation of emissions of meat products from poultry farms and pig farms.

Photo: M. Korepov, M. Timofeev, R. Bekmansurov

Construction of wind farms is a new threat • The data on large birds of prey should be included in the Environmental impact assessment and ecological expertise during wind farms planning. Today, this data is completely ignored that is clearly demonstrated by the example of Ulyanovsk region.

The Volga-Kama region is an important reserve of the White-tailed eagle in the European part of Russia and one of the key areas for studying the WTE

It is necessary to expand research into the territory of the Trans-Urals and Western Siberia

Thanks!

For assistance in conducting research Томаевой И.Ф., Костину Е.С., Бекмансуровой Н.В., Бекмансурову И.Р., Рахматуллину Р.Ф., Кутушеву Р.А., Лебедеву Ю., Салмину А.Е., Шашкину М.М., сотрудникам Волжско-Камского заповедника, ГПКЗ «Спасский», ГПКЗ «Чистые луга», ГПКЗ «Долгая Поляна»