The aim of the study (carried out 25 km south of Poznań, western Poland) was to determine the impact of Red Fox on bird abundance on farmland. Bird abundance was studied in the years 1999-2000 and 2005-2007 in three categories of sampling plots: 1) in small woods — with or without active fox dens, 2) along transects — starting from dens and running across arable land, and 3) around points — located at dens and far from them. Thus, variability in bird density was analyzed in relation to the presence/absence of Red Fox (in woods) and to the intensity of Red Fox penetration of crops (approximated by distance from a den). Two groups of bird species were distinguished with respect to their vulnerability to Red Fox predation pressure: 1) potential fox prey, i.e. species nesting on the ground and in low vegetation; and 2) birds not threatened by foxes, i.e. species nesting in tree holes and in tall vegetation. To investigate the relationships between bird distribution and Red Fox dens in woods, a step-wise multiple regression of bird density and species number on woodland structure was first performed. The residuals derived from the model were used to evaluate the impact of foxes by analyzing the differences between woods with and without active dens. Neither the species number nor the bird density differed significantly between woods with and without active dens. The differences in bird density observed between years in woods with or without active dens were not significant, either. No relationship between bird density in crop fields and distance from fox dens was found. The results are contrary to those of earlier studies and show that Red Fox does not affect farmland bird distribution, diversity and abundance, at least in the short term.
The process of establishing breeding populations of birds in small towns of Central Europe provides a unique opportunity to study them during synurbization in statu nascendi. Over the years 2006-2011, we investigated the breeding ecology of three coexisting thrush species Turdus spp. in the urban habitats of the town of Bardejov (NE Slovakia). We studied nest distribution, nest predation in relation to nest placement and the breeding success of the Common Blackbird T. merula, Fieldfare T. pilaris and Song Thrush T. philomelos. The study species differed significantly in terms of microhabitat characteristics and vertical spatial distribution, expressed as the nest location height (Blackbird < Song Thrush < Fieldfare), the distance from the town centre (Fieldfare < Song Thrush < Blackbird), the distance from the nest tree to human paths and buildings (Blackbird < Song Thrush < Fieldfare) and the average distance between breeding conspecific pairs (Fieldfare < Blackbird < Song Thrush). We also found significant differences in nesting microhabitats (conifers, deciduous trees and shrubs) usage (breeding in conifers: Song Thrush < Blackbird < Fieldfare). On the other hand, no significant differences were found in breeding success and predation between species. A major factor affecting the predation rate was the distance between nests and the distance to human paths and buildings, and with Fieldfares and Common Blackbirds also the height of trees and the distance to the town centre. Our results suggest that ecological segregation among closely related species can also be common in a changed, urban environment.
The sites of 87 brown bear Ursus arctos Linnaeus, 1758 attacks on livestock (horses, cattle, sheep, goats) were investigated in the Cantabrian Mountains, Spain. Ninety percent of livestock predation occurred between May and October, while attacks were most frequent during the months of May and July. There was no difference in overall attack rates between the first and second part of the year, nor among livestock type or age-class. Bears were not selective predators of livestock type or age-class, but had a slight tendency to attack more cattle and adult animals. Bear tracks and scats were found at slightly more than half of the sites visited, while bed construction and food-caching behaviour was rarely detected. Attacks were initiated most times on the neck and the head region. Muscle tissue and soft organs were most preferred body parts consumed by brown bears.
Adult and sub-adult otters Lutra lutra (Linnaeus, 1758) caught and consumed 3.36 prey (fish) per hour (n = 32 captures). This represents 273.8 g of wet mass/h of activity outside the rest sites (10.5-13.1% of the day) and it is enough to get their daily needs. Otters ate the prey without hiding on average (n = 93) 0.46 m from the bank (up to 3.9 m) and 0.25 m above water level (up to 2.05 m). Prey weighing less than 150-200 g were consumed entirely; for this reason prey remains are very rare (except large trout, American crayfish and gravide cyprinid females). Unpleasant tasting or toxic parts and sharp or wide parts of the bones, scales, teeth, claws, heads or leggs in large prey were not eaten.
Small insectivores and rodents, despite similarities in body size and attributes scaling to body size, exhibit significant differences in other properties, including many life history traits. In this article major differences between life history traits of the two taxa are reviewed, with an indication of contrasting selection pressures related to somewhat different body size, as well as to differences in metabolic rates, diet and exposure to predation. Additionally, since the life history differences between small mammals are particularly well pronounced in highly seasonal habitats, the winter ecology of shrews and rodents is compared. Finally, the two different reproductive strategies typical for soricine shrews and small nonhibernating rodents, are presented. In conclusion, it is proposed that the reproduction delayed to the second calendar year of life in shrews is the result of selection for traits ensuring successful survival in winter, a period that is more perilous for shrews than for rodents. In rodents, in contrast, opportunistic reproduction is the most prominent characteristic which also helps to maximize their reproductive output. This ability for high reproduction seems to be the main antipredatory measure selected for in rodent evolution.
Rodent dynamics was once equated with 3-4 year cycles but is now understood to be many-facetted. In a typology of dynamics, including stable and resource-driven populations, extensive cycles and travelling waves appear to have many features in common. They differ mainly in the spatial extent of the cycles or waves. Both types of dynamics demonstrate lag phases. Lagged dynamics may be caused by several agents but specialist and nomadic predators are particularly evaluated in this treatise. The main conclusion is that present understanding of predator effects is limited and partly contradictory. The understanding of local dynamics, on a km -scale, might be facilitated by considering most rodent populations as partially subdivided with patches, on a hectare-scale, differing in quality and release of dispersers; an overflow to suboptimal patches (a 'mass effect') may emerge at fairly unlimited immigration. Dynamics may vary along several gradients, and spatially and temporally limited studies may only catch fragments of extensive population changes. Detailed local studies have to be complemented with extensive monitoring of dynamics.
The effect of mowing on nextyear nest predation was studied in grassland areas on the outskirts of Cracow (south Poland). In 2004 and 2005, nesting success at three sites with two plots each – one unmowed for 2–3 years and one mowed every year – was assessed experimentally with artificial nests baited with two Japanese Quail Coturnix japonica L. eggs. Biomass samples were collected for estimations of the standing crop of vegetation. Mowing was found to be correlated with nest predation pressure on the unmowed plots in two meadows that had greater vegetation cover. At the third site, nest predation and vegetation cover did not differ between the mowed and unmowed plots. All selected sites were classified as Arrhenatherum elatius grassland. Also birds communities of study sites were similar in regard to occurrence of small ground-nesting passerine species: Grasshopper Warbler Locustella naevia Bodd., Reed Bunting Emberiza schoeniclus L., Whinchat Saxicola rubetra L., Yellow Wagtail Motacilla flava L. Artificial nests were destroyed mainly by corvids and only few percent were recognized as destroyed by mammals. The intensity of nest destruction differed greatly between years, probably because Magpies Pica pica L. were less active in 2005.
Przedstawiono ważki stwierdzone przez autora w żołądkach ryb (lipieni, pstrągów potokowych, tęczowych i źródlanych, okoni, szczupaków i basów wielkogębowych), złowionych na wędkę w Polsce, Włoszech, Finlandii i Francji w latach 1985-2005. Z zasady ważki są rzadko zjadane przez ryby (stanowią mniej niż 1% organizmów stwierdzonych w żołądkach ryb), choć w niektórych ciekach nizinnych i wyżynnych ich rola może być znaczna. W Polsce głównymi gatunkami zjadanymi przez ryby łososiowate są Colopteryx ssp., P. pennipes i Gomphidae, prawie wyłącznie w rzekach nizinnych i wyżynnych. W materiale z Finlandii zwraca uwagę brak Zygoptera. Materiał z Włoch, choć nieliczny, wskazuje na zbliżoną rolę gatunków siedlisk lotycznych i lenitycznych. Generalnie wysoka woda sprzyja zwiększonej dostępności larw dla ryb łososiowatych, zarówno wiosną, jak i latem. W przypadku okonia wydaje się, że konsumpcja ważek wzrasta podczas niskiego stanu wody. Imagines rzadko są zjadane przez ryby (autor stwierdził jedynie trzy takie przypadki).
We analysed the variation of small mammal species composition in the Tawny Owl Strix aluco L. diet in forest habitats of Central European Lowland. We used published and unpublished materials from forest-dominated landscapes in Lithuania (n = 7 locations), Poland (n = 8) and East Germany (n = 1); marginal localities were ca. 870 km from each other. We recorded that in Central European Lowland the proportion of Arvicolidae in the Tawny Owl diet significantly increased, while that of Muridae decreased toward north-east. The proportion of less common rodent species (including Gliridae and Sicita betulina Pallas) in the diet also increased significantly toward NE. We did not record any trend of small mammals diversity along the analysed transect. We suggest that the change of Arvicolidae to Muridae ratio toward north-east can be caused by the replacement of mice with boreal vole species in small mammal community. Small mammal diversity in Central Europe is subject of discussion.
The West European hedgehog, (Erinaceus europaeus, Linnaeus 1758) is widely distributed in Western Europe. However, there is evidence of decline in parts of its range. Changes in agricultural management have partly been the driving force behind the loss of species diversity and abundance, and it has been argued that these changes play a role in the decline of hedgehogs as well. We used a questionnaire to investigate the current distribution of hedgehogs on farmland throughout Great Britain with a focus on different environmental zones. Additionally, we identified environmental correlates that related to the distribution of hedgehogs with the aim to get a better understanding of what is needed to design appropriate strategies targeted at the conservation of hedgehogs. Our study illustrates that, although the impact of several variables was rather ambiguous, displaying positive effects in some environmental zones and negative effects in other, major roads and Eurasian badgers (Meles meles, Linnaeus 1758) can have large scale negative effects on hedgehogs. Farm management related factors did not show a consistent impact on hedgehog presence. Conservation strategies should therefore be aimed at lessening the impacts of major roads and badger presence. Wildlife passages, for instance, may provide hedgehogs safe passages across roads. Additionally, increasing the habitat complexity in order to reduce the impact of predators can be beneficial for prey species, such as hedgehogs, and should be considered as a conservation strategy for them.
The aim of this study was to assess the density and diet composition of free-ranging dogs in Poland. The study was conducted in a field and forest mosaic in the central part of the country in the years 2005–2011. The density of the free-ranging dogs was assessed during night counts along repeated transect routes. The number of dogs seen and the feasible observation area were recorded to calculate density index for each control. The day and night counts captured data on group composition and penetration range. Diets were studied through scat analyses. The dog density ranged from 2.2–3.1 ind. km–2 depending on the area. Most dogs were observed alone, and 40% formed groups of 2 to 5 dogs. Most groups were recorded close to buildings, but the group organisation changed (especially during the daytime) with increasing distance from the buildings: 35% of dogs in the village were in groups, but 55% of dogs formed groups at a distance of more than 100 m from the buildings. The night proportion of dogs in groups was approximately 50%, regardless of the distance. Their scats contained mostly cereal given by farmers. The prey remains were game species: roe deer (1.3% of occurrences in summer and 12% in winter), brown hare (3–4%), small mammals (5–9.5%) and birds (approx. 1.5%). The study demonstrated that the abundance of dogs in the rural areas of central Poland may play an important role in the ecosystem.
The number of ground-nesting bird species in meadows, one of the most vulnerable habitats in the ornithological reserve of Vrana Lake Nature Park has decreased in recent decades. Nest survival rates were investigated in meadows and reed beds using nest predation experiments in late March and in May 2005. Predators damaged 18% of the 50 artificial nests placed in the pasture meadow habitat in March and 22% in May. Daily survival rate of nests were found to be similar in March (97%) and May (96%). In May, 64% of 25 nests located in the reed bed were discovered by the predators, with the daily survival rate of nests (90%) being significantly lower than that of nests in the nearby meadow. The results suggest that the reasons for the decreasing number of nesting bird species may be – instead of the pronounced presence and activity of predators in the area – the shrinkage of meadow area, the lack of buffer zone, the proximity of agricultural lands, and disturbance caused by intensive grazing.
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