.:Tichodroma:.

Tichodroma 33 (2021): 1–20. DOI: 10.31577/tichodroma.2021.33.2

Pôvodná práca / Original paper

Endangered birds of old growth forests in the Pirin National Park, SW Bulgaria: habitat preferrences, distribution and population sizes in 2001-2019
Ohrozené vtáky pralesov v Národnom parku Pirin, JV Bulharsko: habitatové preferencie, rozšírenie a veľkosť populácií v rokoch 2001-2019

Petar SHURULINKOV & Girgina DASKALOVA
National Museum of Natural History – Sofia, Bulgarian Academy of Sciences, Tsar Osvoboditel, 1, 1000
Sofia, Bulgaria; е-mail: p.shurulinkov@gmail.com

Andrey RALEV, Petko TZVETKOV, Kostadin VALCHEV, Simeon ARANGELOV& Ivan HRISTOV
Balkani Wildlife Society, Dragan Tsankov str., 8, 1164 Sofia, Bulgaria

Rumen KOLCHAGOV
“Rila” National Park, Bistritsa str., 12 B, 2700 Blagoevgrad, Bulgaria

Petar DIMOV
Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Tsar Osvoboditel, 1, 1000
Sofia, Bulgaria

Abstract. Actual status, distribution, numbers and threats for four forest bird species – Tengmalm’s Owl (Aegolius funereus), Pygmy Owl (Glaucidium passerinum), Three-toed Woodpecker (Picoides tridactylus), and Capercaillie (Tetrao urogallus) were studied in the territory of the Pirin National Park, Bulgaria, in the years 2001−2002 and 2019. For the owls, we used night line transect, 2−5 km in length, with acoustic imitation of species calls (henceforth playback) at each 500 (700) m (38 points in 2001−2002, 80 points in 2019). Daytime line transects, 2−5 km in length, were used for counting woodpeckers and Pygmy Owl. In Capercaillie counts, we searched for tracks in the snow, excrements or feathers. GIS analyses were applied for visualization of habitat association and distribution patterns of the studied species. The numbers and distribution of these species were compared between the two study periods and with existing data from previous studies. In 2019 a total of 29 occupied territories of Tengmalm’s Owls, 20 territories of Pygmy Owls, 2 territories of Three-toed Woodpeckers and 16 leks of Capercaillies were found. Decrease in numbers was detected for Tengmalm’s Owl (-30.4%) and Capercaillie. These species showed also different spatial pattern of presence between the two study periods. Three- toed Woodpecker population in Pirin NP is very small, not exceeding 10−15 pairs. Pygmy Owl was recorded for the first time during the breeding period in the National Park. The reasons for the differences between the two study periods were discussed. The results indicate some threats (ski tourism development, disturbance by people, sanitary cuttings, etc.) for these birds and can be used for improving the spatial planning of human activities in Pirin NP.

Key words: forest birds, habitat, population size, limiting factors, line transect method

Citácia / Cite as
Shurulinkov P., Ralev A., Tzvetkov P., Valchev K., Daskalova G., Arangelov S., Kolchagov R., Hristov I. & Dimov P.: Endangered birds of old growth forests in the Pirin National Park, SW Bulgaria: habitat preferrences, distribution and population sizes in 2001−2019. Tichodroma 33: 1–20. DOI: 10.31577/tichodroma.2021.33.2

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