Lesser Spotted Eagle in Southeast Bulgaria

Distribution, abundance, breeding performance and habitat requirements of the Lesser Spotted Eagle (Clanga pomarina) in Southeast Bulgaria Dimitar Demerdzhiev, Dobromir Dobrev, Volen Arkumarev, Nikolay Terziev and Georgi Popgeorgiev

Scarce data at national level Until 2014 there was no systematic research on the species In 2007 the national population was estimated at about 350-400 pairs (Iankov 2007)

Breeding Distribution

Methodology The study area was divided into 2x2 km grids We recorded occupied territories, breeding pairs and number of fledglings We estimated productivity (fledglings/occupied territories) and breeding success (fledglings/incubating pairs) 3 000 m radius around the nests (CLC)

77 active nests 167 occupied territories

Most of them in SPAs Sakar, Dervent Heights and Western Strandzha

And less in SPA Strandzha Mnt.

Population underestimated In 2007 the national population was estimated at about 350-400 pairs (Iankov 2007) In Southeast Bulgaria only, the breeding population totals 270-300 pairs

Breeding density Highest density in the Dervent Heights – 7.2 pairs/100 km2 Lowest density in Strandzha Mnt. – 1.7 pairs/100 km2 NND (n=28) ranged from 0.71 km to 4.5 km, mean value of 2.43 km ± 1.15

Breeding performance 131 cases of occupation of territory The productivity varied from 0.44 to 0.55 0.49 on average The breeding success ranged from 0.55 to 0.78 0.65 on average No case with 2 fledglings!

No statistical differences were recorded for the breeding parameters over the years

Highest value of breeding success in Strandzha Mnt. - 1 Lowest in Western foothills of Strandzha - 0.5 In the Dervent Heights - 0.62

Breeding failure

Nest sites

Nesting trees

Position

Tree characteristics DBH – 0.49 m ± 0.11 Height of tree - 15.07 m ± 4.38 Height of nests - 10.03 ± 4.08 (4.5 m - 23 m) Canopy coverage - 71.67%±25.75%

Macro-habitat level Forests – 35.22% Arable land – 22.19% Grasslands – 14.32% Shrubs – 8.67% Semi-natural grasslands – 8.56%

Wood stand Old forests (up to 100 years old), 3.4%

Most of them between 41 and 60 years of age (38.3%)

Different habitats Root 1significantly vs. Root 2 Territories differ between regions 12 (F = 4, p< 0.001) 10 With regard to arable lands, forests and shrubs 8

Root 2

6

4

2

0

-2

-4 -4

-2

0

2

4 Root 1

6

8

10

TV SA DH S ER K

Riparian forests with small percentage of grasslands and prevailing arable lands

Mostly forests, small patches of grasslands, arable land, and shrubs

Mosaic habitat with fragments of forests, patches of grasslands, cultivated fields and shrubs

Threats to the habitats include

Natural succession of open fields

Plowing of grasslands

Improper management of grasslands

Leading to food source reduction

Construction of wind farms and solar parks

Fires

Population future

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