/99): 85-86. Vrezec, A. (2000): Veliki skovik Otus scops . - Acrocephalus 21 (98/99): 85. Vrezec, A. (2001a): Eurasian Scops Owl Otus scops . - Acrocephalus 22 (106/107): 121-132. Vrezec, A. (2001b): Gnezditvenagostota velikega skovika Otus scops v urbanih okoljih polotoka Pelješac v južni Dalmaciji. - Acrocephalus 22 (108): 149-154. Zuerogoitia, I. & Campos, L. F. (1998): Censusing owls in large areas: a comparison between methods. - Ardeola 45 (1): 47-53.
The altitudinal distribution, breeding density and population size of Tengmalm’s Owl Aegolius funereus was studied in Kopaonik National Park (central Serbia) during the 2011 and 2012 breeding seasons. The size of the study area was 24 km2. The survey method applied was a line transect in combination with stop points and playback of territorial male call. During the two-year research project, 37 territories were located. In Kopaonik National Park, Tengmalm’s Owl males inhabit Norway Spruce Picea abies, mixed Norway Spruce-Silver Fir Abies alba and Norway Spruce-European Beech Fagus sylvatica forests in the altitudinal belt stretching between 1,367 and 1,689 m a.s.l. The breeding density in the studied area was 8.3 territories/10 km2 in 2011 and 7.1 territories/10 km2 in 2012. Total population estimate of Tengmalm’s Owl in Kopaonik National Park is substantially higher than previously assumed, its 42-49 breeding territories making it currently the most important breeding site in Serbia.
Nest-site characteristics and breeding density of Magpie Pica pica in Sombor (NW Serbia)
In March 2009, active Magpie Pica pica nests were censused in the town of Sombor (Vojvodina, NW Serbia) to study nest-site characteristics, breeding density and spatial distribution. The area of the town can be divided into two parts according to different urban landscapes, i.e. the town centre (150 ha) and the residential area (2,224 ha). In total, 222 Magpie nests were found and their height, tree species and nest-site type determined. Nests were found in 25 tree and two shrub species, the most of them (31.1%) being placed in the commonest tree species in the town, the Common Hackberry Celtis occidentalis. The majority of the nests were found in tree avenues (39.6%) and groups of trees (31.5%). Nests in the town centre with a mean height (± SD) of 15.2 ± 4.05 m were significantly higher than those in the residential area with a mean height (± SD) of 11.4 ± 5.13 m. The mean distance of nests from the top of the canopy (± SD) was 1.5 ± 1.33 m, demonstrating the Magpie's tendency to place its nests in the very tops of trees in the urban areas. In the residential area, nests were present in every height class, while in the town centre they were not found lower than 5 m. This difference can be explained by denser human population in the town centre and hence greater disturbance (e.g. pedestrians), as found in several other studies, but also by the negative effect of high buildings that prevail there. Thus, the height of surrounding buildings, too, might play an important role in nest-site selection in Magpies breeding in urban habitats, especially in densely built-up areas. Breeding density of Magpie in Sombor was 0.94 pairs/10 ha, with almost twice as high in the town centre as in the residential area. The findings of this study are compared to those obtained in other studies in Serbia and abroad.
Numenius arquata. - Acrocephalus 30 (141/142/143): 217. Štumberger, B. (2009d): Kaspijska čigra Sterna caspia. - Acrocephalus 30 (141/142/143): 218-219. Štumberger, B. & Denac, D. (1994): Pojavljanje in gnezditvenagostota malega ponirka Tachybaptus ruficollis v ormoških bazenih. - Acrocephalus 15 (62): 8-16. Štumberger, B. & Šorgo, A. (1995): Dnevni prelet vodnih ptic v dravski loki pri Ptuju - prezimovanje ali selitev? - Acrocephalus 16 (68/70): 72-78. Tarman, K. (1992): Osnove ekologije in ekologija živali. - Državna založba Slovenije, Ljubljana. Tome, D