Numbers and habitat preferences of the Barred Warbler Sylvia nisoria on the floodplain terrace of the lower Vistula River.

Tomasz Brauze

Abstract: Between 1998 and 2000 densities of the Barred Warbler were estimated in various habitats of the Vistula River floodplain terrace between Włocławek and Solec Kujawski. The recorded density of this species on 3660 ha of landscape area was 1.5 pairs (singing males) per 1 km2. Local densities recorded during one breeding season on three plots studied with the mapping method ranged from 0.8 to 3.3 pairs per 10 ha, and on seven line transects - from 0 to 2.3 pairs per 1 km (pairs per 10 ha). The highest densities were recorded in narrow belts of shrubs and riparian forest adjacent to open areas. High densities of the Barred Warbler and its high frequency on the study plots studied by the mapping method (100%) and on line transects (86%) were connected with strong fragmentation of shrubs and riparian forest which create numerous ecotones. According to these results the lower Vistula valley is one of the largest, not described, concentrations of the Barred Warbler population in Poland. The average density of this species in areas where the mapping method and line transects were used - 15 pairs per 1 km2 - was ten times higher than the density in the landscape area studied. These results indicate that the Barred Warbler numbers obtained during the large areas studies are underestimated. A compromise between the relatively accurate estimates of this species abundance and conducting study in large areas of river valley seems to be application of the line transect method.

Species composition, numbers and age structure of gulls Laridae wintering at rubbish dumps in Poland.

Włodzimierz Meissner, Jacek Betleja

Abstract: One hundred rubbish dumps were surveyed in mid-January 2002, 2003 and 2004. Average numbers of gulls per one rubbish dump were similar in northern and central Poland (2.4-3.9 thousand inds) and very low in the southern part of the country (only 27-80 inds). Overall, 42-55 thousand Herring Gulls sensu lato (including the Herring Gull Larus argentatus, Caspian Gull L. cachinnans and Yellow-legged Gull L. michahellis), 5-6.9 thousand Common Gulls L. canus, 900-2500 Black-headed Gulls L. ridibundus and 300-1000 Great Black-backed Gulls L. marinus were recorded. Herring Gulls s.l. predominated over other species, making up 90% or more of all gulls in central and northern Poland. In southern Poland, Common and Black-headed Gulls predominated (91% in total) over Herring Gulls, whereas Great Black-backed Gulls were recorded in northern and central regions exclusively. Among Herring Gulls s.l., L. argentatus were most numerous in northern and central Poland (91.2-99.6%), whereas the Caspian Gull predominated in southern Poland (88-98% of all Herring Gulls s.l.). Yellow-legged Gulls were scarce (0-0.1% of all Herring Gulls s.l.). Other recorded species involve 5 Glaucous Gulls L. hyperboreus and 12 Lesser Black-backed Gulls L. fuscus. It seems that the geographical location, distance from non-freezing roosting places, size of the area used to store rubbish on the dump and interspecific competition are among the main factors shaping the species structure of gulls on rubbish dumps.

Effect of the territory's habitat structure on the Barn Owl Tyto alba diet in central-eastern Poland.

Agata Urbanek, Grzegorz Pyziołek

Abstract: The paper provides an analysis of Barn Owl pellets from agricultural area of central-eastern Poland collected in 1990-2001 at 23 sites which had been occupied by this species for a dozen or so years. From the pellets, 22 015 remains of vertebrates representing 27 species, mainly small mammals (97.9%) but also birds (1.8%) and amphibians (0.2%), were isolated. The predominating species were the House Mouse Mus musculus (6442 inds), Common Vole Microtus arvalis (6427) and Common Shrew Sorex araneus (4801). Statistically significant relations between the habitat types distinguished within territories of individual owls and four main prey species composing the diet were noted. The Common Shrew share was found positively correlated with the proportion of forests and groves, and negatively with the percentage of farmland. The Lesser Shrew S. minutus occurrence was positively correlated with the proportion of human settlements and negatively with that of ploughland. The frequency in the diet of the Root Vole M. oeconomus increased with the percentage of settlements increasing and declined with an increase in the area occupied by farmland. The House Mouse was the most common in the territories with the greatest share of farmland and the least frequent in ones characterized by the highest share of settlements. Besides, the Barn Own diet in central-eastern Poland was found different qualitatively from that in the western part of the country. In the pellets collected in Masovia the most numerous species were the Common Shrew and House Mouse, whereas remains of the Common Vole were definitely less abundant.

Avifauna of the Międzyodrze region in 1994-2006.

Łukasz Ławicki, Dominik Marchowski, Wojciech Mrugowski, Sławomir Niedźwiecki, Jacek Kaliciuk, Przemysław Śmietana, Dariusz Wysocki

Abstract: In 1994-2006, within the Międzyodrze (area between two arms of the Odra River) occurrence of 210 bird species was recorded, including 124 breeding ones. On the national scale, populations of the following species highly abounded with breeding pairs: the Greylag Goose Anser anser - 30-40, Gadwall Anas strepera - 60-75, Garganey A. querquedula - 40-50, Shoveler A. clypeata - 30-35, Bittern Botaurus stellaris - 26, Grey Heron Ardea cinerea - 400, Marsh Harrier Circus aeruginosus - 29-33, Spotted Crake Porzana porzana - ca 30, Water Rail Rallus aquaticus - 150-200, Common Snipe Gallinago gallinago - 34, Black Tern Chlidonias niger - 64, Thrush Nightingale Luscinia luscinia - 350-400 in 1995, Bluethroat L. svecica - 45-55, Savi's Warbler Locustella luscinioides - 600-700 and Common Rosefinch Carpodacus erythrinus - 90-130 in 1995. In the study period 10 species from the "Polish Red Book of Animals" bred in the area. This region is important to waterbirds during the migration and wintering season. The Common Crane Grus grus and Greylag Goose were observed here in record numbers - up to 14 500 and to 5 000 inds respectively, and the concentrations of geese and ducks exceeded 20 000 birds. During the last 10 years the abundance of many breeding species drastically declined, and some, e.g. Montagu's Harrier C. pygargus, Black-tailed Godwit Limosa limosa or Aquatic Warbler Acrocephalus paludicola, even ceased breeding in the area. This can probably be related to the succession of reed and shrubs into open areas which results in loss of habitats used by these birds and to increased predation by mammals.