Studies were carried out in 2010 by mean of simplified version of the mapping method. The study area (395 ha) was located close to the city centre. It comprised a mosaic of urbanized habitats, with a clear dominance of green areas, such as parks (41.1 ha), gardens, cemeteries and tree clumps. A total of 48 breeding bird species were recorded in the whole study area. The most common (<25 pairs/100 ha) were Passer domesticus, Passer montanus, Sturnus vulgaris, Parus caeruleus, Parus major, Apus apus and Columba livia. Numerous (7-15 pairs/100 ha) were also the following species: Columba palumbus, Turdus pilaris, Sylvia atricapilla, Serinus serinus, Turdus merula and Pica pica. Insectivorous birds were the most common birds constituting 63.3%, and granivorous -32.6% of all pairs recorded. Most birds nested in tree holes (39.3%), in/on buildings (30.2%) and in trees/shrubs (25.6%). Distribution of breeding pairs of 23 bird species was presented on maps. Population trends for 17 species were documented. Rapid increase in numbers of Turdus pilaris, Corvus cornix and Phoenicurus phoenicurus and decrease of Pica pica were recorded.
Breeding bird community in a densely built-up area (mainly block buildings with abundant trees and shrubs) in the city of Wroclaw (96.8 ha) were compared between the year 1996 and 2009. In 2009, 25 breeding species were recorded. Columba livia and Passer domesticus were eudominants comprising together 60.2% of the bird community, while Apus apus and Passer montanus were dominants (together 11.1%). The most common were granivores (66.8%; 4 species) and insectivores (19.0%, 14 species). In comparison with 1996, the following species have increased in numbers by the year 2009: Columba palumbus, Pica pica, Corvus cornix, Parus caeruleus, Passer montanus, Carduelis chloris, Sylvia atricapilla, Falco tinnunculus and Turdus pilaris; while Corvus monedula, Phoenicurus ochruros, Turdus merula, Fringilla coelebs, Muscicapa striata, Hippolais icterina and Streptopelia decaocto have decreased.
The Eurasian eagle-owl (Bubo bubo) diet in the Orava Region (N Slovakia)
Food remains of the Eurasian eagle-owl (Bubo bubo) were studied in samples collected from 26 nests. The samples were collected during spring thus represent the prey brought to the nest whilst rearing of chicks. In total 15,196 items of prey were determined. The dominant food items were two smaller species of rodents, Microtus arvalis (39.0%), Arvicola amphibius (12.1%), and the common frog (Rana temporaria; 27.9%). Other prey recorded had low dominance, however, represented a wide range of species. 43 species of mammals and over 80 species of birds were determined. The Orava Region is climatically one of the coldest regions in Slovakia. The abundance of food for nestlings depends mostly on gradational cycles of small species of rodents and on frogs as the alternative food components. The proportion of bigger species of prey is low: from mammals it was mainly Rattus norvegicus (2.3%), Erinaceus roumanicus (0.7%) and Lepus europaeus (0.5%), from birds Corvus cornix (1.1%), Perdix perdix (0.6%) and Asio otus (0.4%). The food supply creating suitable condition for reproduction of Eurasian eagle-owls in the Orava Region has been deteriorating over the last 20 years due to a decrease in agricultural production leading to diminution of non-forest areas.
There is a lack of data on the population densities of birds breeding in a mosaic of typical urbanized habitats. This study was undertaken to partly fulfil this gap in our knowledge. Counts were conducted in 2008 by means of simplified territory mapping method in a fragment (1197 ha) of a large Central European city (Wrocław, SW Poland). In total, 50 bird species were breeding in the study area in 2008. The House Sparrow Passer domesticus, Common Swift Apus apus and Rock Dove comprised about 3/5 of all breeding pairs. The other group of species, each one with a density between 6 and 13 pairs per 100 ha, included seven species, namely the Starling, Sturnus vulgaris, Greenfinch, Carduelis chloris, House Martin, Delichon urbica, Tree Sparrow, Passer montanus, Great Tit, Parus major, Blue Tit, Parus caeruleus, and Jackdaw, Corvus monedula. They comprised together about 1/5. The remaining 40 species nested in a density between 0.1 and 3.5 pairs per 100 ha. The most numerous feeding guild were granivores (53.8%) and insectivores (37.9 %). Birds nesting on buildings comprised together 74 % of all breeding pairs. For a few species (Luscinia megarhynchos, Saxicola torquata, Corvus cornix and Turdus pilaris) an increase in their numbers in the last three decades has been evidenced.
From 28 Sep to 7 Oct 2012, bird collisions with the glass façade of a commercial building in the centre of Ljubljana were monitored. The observations lasted 45-60 minutes in the morning (7.00-10.00 hrs), around midday (11.00-14.00 hrs) and in the afternoon (15.00-18.00 hrs). Behaviour of all birds and scavengers, which could potentially be looking for bird carcasses in the vicinity of the building, was noted. In 27.25 hours of observation, 16 collisions (3 resulting in death, 13 cases with birds flying away seemingly unharmed) and 19 near collisions, when birds avoided the building at the last moment before collision, were recorded. The total collision rate was 0.59 collisions per hour of observation. All birds that collided with the building, except Feral Pigeon Columba livia f. domestica, were passerines, among which tits Paridae predominated (62.5% of birds that collided with the building). The glass façade functioned as a mirror, reflecting tree crowns from across the street. Data show that most collisions occurred in the middle part of the building during the morning. Among potential scavengers, domestic cat Felis domesticus and Hooded Crow Corvus cornix were observed. The latter regularly flew around the building during the observation period, possibly looking for bird carcasses.
In 2010, an attempt was made to quantify bird species breeding in the Opava Mts. and their foothill (c. 135 km2, including c. 40 km2 [31%] of forests). The area is situated in the extreme south of Opole Silesia, SSW Poland. For most non-passerine species, total counts were made for the whole area (distribution of their breeding pairs is shown on maps), while for most passerine species, semi-quantitative studies were conducted. A total of 116 breeding and two probably breeding bird species were recorded. Changes in breeding avifauna of the area during the years 1880-2010 are also analysed based on literature search. A total of 134 breeding bird species were recorded over the 130 years. During the years 1990-2010, decreae in numbers has been evidenced for the following species: Perdix perdix, Tetrastes bonasia, Tyto alba, Athene noctua, Corvus frugilegus, and Nycifraga caryocatactes, In the same period, increase in numbers has been documented for species such as: Accipiter gentilis, Falco tinnunculus, Columba oenas, Jynx torquilla, Dryocopus martius, Picus canus, Picus viridis, Motacilla cinerea, Luscinia megarhynchos, Phoenicurus phoenicurus, Saxicola rubicola, Locustella naevia, Locustella fluviatilis, Corvus corax and Corvus cornix. Opava Mts. and its foothills constitute an imporant conservation area. Fifteen species listed in Annex I of the Bird Directive of the E.U. were recorded there, including a sizable population of Ficedula albicollis.
Niemodlin countryside (c. 300 km2) is situated in the south-western part of Opole Silesia, SW Poland. Forests occupy c. 40%, arable grounds – 1/3, and meadows and pastures – 7%. There are 31 fish-ponds with a total diked surface of 663 ha. The paper presents results of field investigations carried out during the years 2002-2007 and an analysis of changes in the breeding avifauna over the last 56 years. During the years 2002-2007, 123 breeding and 11 probably breeding bird species were recorded in this area. During the years 1962-2007 151 species were recorded as breeding residents; and additional five species – as probably breeding resident. The following species were recorded as breeding for the first time in 1962-2007: Haliaeetus albicilla, Larus canus, Motacilla cinerea, Saxicola torquata, Locustella luscinioides, Ficedula albicollis, Corvus corax and Carpodacus erythrinus. In the same period the following species became extinct: Podiceps nigricollis, Anas clypeata, Milvus milvus, and Tringa glareola. The following species increaed in numbers in 1962-2007: Coturnix coturnix, Grus grus, Columba oenas, Apus apus, Dryocopus martius, Dendrocopos medius, Motacilla cinerea, Saxicola torquata and Corvus corax. In the same period, Tachybaptus ruficollis, Podiceps cristatus, Podiceps grisegena, Ciconia ciconia, Aythya nyroca, Perdix perdix, Gallinago gallinago, Larus ridibundus, Tyto alba, Alcedo atthis, Picus viridis, Riparia riparia and Corvus cornix decreased in numbers. The areas with the highest concentration of rare and endangered species are postulated to be protected as nature reserves, landscape parks and other spatial forms of nature conservation.
In the period between the years 1976 to 2016 we monitored the nesting site distribution of two populations of saker falcon (Falco cherrug) concentrated in the highlands and adjacent lowlands of western and eastern Slovakia. In western Slovakia we recorded nesting by 56 pairs and 514 nestings, and in eastern Slovakia we observed nesting by 32 pairs and 245 nestings. There were similar nesting success rates in both regions, with pairs producing on average 3.2 young in every successful nest. During the monitored period as a whole a total of 1,788 young saker falcons were raised. At the same time all the pairs gradually resettled in the lowlands, and in the new environment the nesting success rate significantly improved (81.1% compared with 57.1 % in the highlands). This change of nesting biotopes was caused by the impacts of intensive exploitation and environmentally inappropriate forest management, with the accompanying excessive disturbance of nesting birds, but at the same time the disappearance of ground squirrel (Spermophilus citellus) colonies led to a change in the food spectrum for the observed saker falcon pairs. We evaluated the falcons’ feeding habits in western Slovakia between the years 1977 and 2016 (49 pairs; 1–17 pairs/year) and in eastern Slovakia between 2009 and 2016 (12 pairs; 1–3 pairs/year). Altogether 17,669 prey items were identified. From 1976 onwards mammals (Mammalia, 19.8%, 24 species) became gradually less represented as a component in the falcons’ diet compared with birds (Aves, 79.9%, 58 species). In areas of western Slovakia we found stable and predominant proportions of domestic pigeons (Columba livia f. domestica) ranging from 52% to 62%. The proportion of pigeons was distinctly lower in eastern Slovakia (31.5%), compensated for by larger shares of common vole (Microtus arvalis), common starling (Sturnus vulgaris), Eurasian magpie (Pica pica) and hooded crow (Corvus cornix). The common starling (9.5%) was a significant prey species in the lowlands of western and eastern Slovakia alike. Mammals were mostly represented by common voles (9.8%), European hamsters (Cricetus cricetus, 5.3%), ground squirrels (2.1%) and hares (Lepus europaeus, 1.6%). Changes over time in the composition of falcons’ prey were also evaluated over five periods in western Slovakia.
. – Biodiversity and Conservation 7: 1013. Z duniak P., K osicki J. Z., G ołdyn B. (2008): Un-paint it black: Avian prey as a component of the diet of nestling Hooded Crows Corvuscornix . – Belgian Journal of Zoology 138 (1): 85–89.
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