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EN
Despite the high taxonomic diversity, wide distribution and important ecosystem functions of snails, their ecology remains obscure, and this can hamper their conservation. Overwintering in the studied population of Vertigo moulinsiana is effective enough to allow the majority of it to survive. The population dynamics of V. moulinsiana is specific, where the summer boom in a suboptimal habitat covering a small area (wet patches of sweet grass) can determine the snail's range over much larger areas. Our results suggest that humidity could have been the major factor governing population increase. The summer boom is caused by juveniles appearing in very large numbers during this period, thus the peak height is mostly influenced by the considerable susceptibility of juveniles and eggs to desiccation. The limiting influence of humidity is evident in the unequal spatial distribution of individuals: the wetter the substrate, the greater the abundance of snails. As a consequence, the boom may be spatially regulated and only occurs in wet habitats, even though the snail actually occupies a much larger area. Our results indicate that this V. moulinsiana population does not follow typical models constructed for vertebrates or other animals with high dispersal abilities, like the Ideal Free Distribution (IFD) model, and requires a specific approach. Its specific spatiotemporal pattern should be taken into account during monitoring surveys and conservation actions.
EN
Numbers of wintering Natterer's bats Myotis nattereri (Kuhl, 1817) and Daubenton's bats M. daubentonii (Kuhl, 1817) were monitored at seven study sites (three single large hibernacula and four groups of roosts) in central Poland. The longest monitoring period was 1987-2009, the shortest - 1999-2009. The aim of the study was to find out if the numbers of the two species are stable, or if any trends could be detected. For most of the study period, bats were counted twice during each hibernation season: in autumn (November/December) and in winter (January/February). The numbers of Natterer's bats show a strong increase all over the study area - a trend similar to that reported earlier from other parts of the country. Daubenton's bats, on the other hand, declined in the hibernacula located in the north-eastern part of the study area, while in those located in the south-western part their numbers were stable or even slightly increased. A decrease in the numbers of Daubenton's bats is in contrast with reports from other hibernacula in Poland and elsewhere in Europe, where the species increases in numbers. The changes in the numbers of both studied species could be explained by neither changes in the hibernacula nor weather conditions during the study period, so our results probably reflect changes in the numbers of local populations.
3
Content available remote Supermarkets - a wintering habitat for House Sparrow Passer Domesticus L.
EN
Animals often co-exist with humans inside buildings, however in birds such cases are only sporadically noted. In this paper we describe the occurrence of House Sparrows in supermarket interiors. The probability of House Sparrows presence was higher in larger markets and during winter period. The abundance and density of birds were positively and negatively related to the size of the supermarket, respectively. The birds were active at night. They foraged mainly along market shelves on bakery products, vegetables and cereals. We did not observe nesting inside market halls. The supermarkets seem to be hospitable wintering place for this species, however they may also be ecological traps imprisoning the birds once they find their way in. Moreover, House Sparrows may contaminate food, thus, the presence of such species inside supermarkets should be controlled.
EN
A study of wintering Common Crossbills (Loxia curvirostra L.) was conducted in the winter periods 2002/2003-2006/2007 in the Western Carpathians. Birds were surveyed on transects in natural mountain European beech (Fagus sylvatica L.)-Silver fir (Abies alba Mill.)- Norway spruce (Picea abies (L.) Karst.) forests of the Tatra Mts, Pieniny Mts, Babia Góra Mt. and Gorce Mts (total length 41.4 km) as well as in a habitat mosaic with Scots pine (Pinus sylvestris L.) and Mountain pine (Pinus mugo Mill.) stands in the Kotlina Orawsko-Nowotarska valley (total length 31.5 km). Birds mean density underwent annual changes from 1.9 to 15.5 ind. 10 km[^-1] in the natural mountain forests and from 0.9 to 12.1 ind. 10 km[^-1] in the habitat mosaic. The median flock size in the natural mountain forests was 2, and it varied from 1 to 4 in subsequent seasons. They were smaller than flocks recorded in the habitat mosaic in the valley - median 2.5 (from 2 to 7 in subsequent seasons). The size of foraging and flying flocks did not differ significantly in natural mountain forest nor in the valley habitat mosaic. In the natural mountain forests, birds preferred habitats dominated by Norway spruce, and avoided European beech-Silver fir forests. The median flock size was 2 in habitats with Norway spruce, and 8 in stands where Norway spruce was absent. The variation in bird density presumably reflected the changes in quantity and location of food resources. Birds moved within stands with varying proportions of Norway spruce in the mountains as well as between the mountains and the valley, where habitat with mosaics of Scots pine and Mountain pine dominated.
5
Content available remote Influence of low temperatures on behaviour of mallards (Anas platyrhynchos L.)
EN
Periods of severe winter weather are associated with increased food consumption and metabolic rates. Depending on food availability birds could use different strategies to maintain homeostasis. Mallards Anas platyrhynchos L. numerously winter in urban parks, where people feed waterfowl bread. This food source is easily digestible and provides a high energy, which may affect bird behaviour. Studies were conducted in two consecutive winters in the Gdańsk-Oliwa city park in northern Poland, a place where people feed mallards, bread daily. During the period of lowest temperatures (about -12[degrees]C) females spent only 6% of their time foraging, while males spent 17% foraging. During mild winter weather (mean temperature about -2[degrees]C) foraging took up 21% of time budget in both sexes. In the colder period a three fold increase in male agonistic behaviour was observed when compared to the mild period observations. Females spent the most of harsh winter period inactive, apparently relaying on accumulated energetic reserves. Males cannot reduce all activities like females, because pairing in mallards takes place mainly in autumn and early winter and males need to attract actively, display for, and defend mates.
6
Content available remote Long-term population trends of corvids wintering in urban parks in central Poland
EN
Changes in the numbers of corvids wintering in Warsaw (Central Poland), in the last sixteen years were analyzed. Four species were studied: Rook Corvus frugilegus L., Jackdaw C. monedula L., Hooded Crow C. corone cornix L. and Magpie Pica pica (L.) The results were based on density data for birds foraging in three urban parks. The bird counts were conducted in November and December 1988.2003. It was found that the number of wintering Rooks decreased significantly (0.5 fold), populations of Jackdaws and Hooded Crows - increased (4.25 and 3.95 fold, respectively), and no apparent trends were observed for Magpies during this period. Observed trends for Rooks as well as comparisons of limited data gathered earlier in other areas may confirm suggestions about the changing of migration routes of this species.
EN
In winter 2004/2005 some exceptionally large (on the Central European scale) concentrations of Snow Bunting (Plectrophenax nivalis), up to 1600 individuals, were recorded in Lower Silesia (south-western Poland). The Snow Bunting flock size was positively correlated with the mean daily air temperature (P = 0.002). The average flock size during snowless days was 11 times higher than in the snowy period (P = 0.0017). One of the factors encouraging the more abundant wintering of Snow Bunting in Central Europe may be the milder climatic conditions, especially higher temperature and lack of snow cover. During the last four decades the rise of mean temperatures and shrinking of the snow cover period in winter months (December-February) have been observed in Lower Silesia.
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