Absence of accuracy in species recognition can lead to inter-specific mating and hybridization. Aside from acoustic signals, bats can also use olfactory signals to search for mates. We compared the level of attractiveness of facial glands scents and urinary scents for discrimination in two cryptic bat species. Both sexes of two sympatric bat species Pipistrellus pipistrellus and P. pygmaeus were used as model. Possible sexual preferences using two olfactory signals were studied in a dual choice experiment in a glass Y-maze. Both sexes, without reference to the species, performed lower searching activity in tests with urinary scents than in the case of signals composed of scents of facial glands. Males of both species were able to discriminate and prefer the odour of conspecific females, with small proportion of disassortative choices. Females of both species did not have species-specific preferences. Absence of females' odour preferences and small proportion of males' disassortative choices can provide theoretical background for the existence of inter-species hybridization or point at more important role of acoustic signals in pre-mating behaviour.

Invasive American mink and native polecats were live-trapped over a period of six years and radio-tracked during one winter-spring season in the lakeside habitats in NE Poland. The number of mink declined whereas number of polecats was stable during 1995–2000, however, except during one winter, mink were always more abundant in the study area than polecats. Significant differences in habitat utilization between radio-collared mink and polecats were observed. Mink moved only along the lake shoreline and showed no seasonal shift in habitat selection. In winter, polecats were most frequently located close to the lake banks, but they also stayed in barns and stables. In spring, they moved further from the lakes. There was considerable interspecies overlap of mink and polecat home ranges in February, and common use of the banks of the 500 m long unfrozen canal was recorded for 4 mink and 5 polecats. The pattern of daily activity of polecat and mink differed: mink were most active at dawn and in early morning whereas polecats at dusk and in beginning of the night. Individuals of both species coexisted in this small area at relatively high densities and to some degree exploited the same habitats, particularly in the vicinity of sites with access to open water.

Although it is well known that bats commonly forage in riparian areas, which provide water resources and insect concentrations, the role that the physical structure of riparian areas plays in influencing local bat communities is less certain. In 2000–2002, we used acoustic monitoring to determine bat species presence at 338 riparian sites in northwestern Georgia, USA. We used a 2-dimensional nonmetric multidimensional scaling (NMDS) ordination to assess how separations among species were partially associated with riparian conditions. Our NMDS analysis found some degree of habitat partitioning among bat species occurring in northwestern Georgia and was dictated in part by riparian condition. Myotis grisescens and M. septentrionalis were associated with low-elevation lotic waterways, whereas M. lucifugus, Lasiurus borealis, and Eptesicus fuscus were associated with high-elevation lentic waterways with sparse canopy cover. However, riparian conditions had weak relations with NMDS axes, possibly resulting in coincidental associations in some cases. Regression tree analysis indicated that higher bat species richness was associated with apparently uncommon small, high-elevation waterways with sparse canopy cover as well as larger streams and rivers that had wetlands adjacent to them. Including high-elevation waterways with existing management recommendations for endangered M. grisescens foraging areas (large, low-elevation streams and rivers) will be the most effective conservation strategy to benefit the most bat species in northwestern Georgia and probably elsewhere in the southern Appalachians.

This is a report on a post-lactating female soprano pipistrelle, Pipistrellus pygmaeus, which in autumn exploited habitats from sea level to the transition zone between alpine and sub-alpine areas. It travelled more than 12.3 kilometres from its roost and returned to its roost at sea level on all four nights when it was tracked. In addition to the telemetry bat, several soprano pipistrelles utilized high altitudes during the days of tracking as heard on ultrasound detector.

The effects of weather and individual attributes of the broods in the local population of tawny owl Strix aluco on recruitment were studied in the Duna-Ipoly National Park, Hungary (47°35′ N; 19°02′ E) in 1992–2007. In harsh breeding conditions, with many snowy days, the parents' body condition was low and they were able to raise only few fledglings. Nevertheless, the few fledglings remaining in this reduced broods left them in better condition and had a greater chance to be recruits than offspring which fledged in mild seasons, with many siblings, from broods raised by the parents in good condition. Parents produced most male recruits in adverse breeding seasons, when one offspring fledged from the broods, but raised most female recruits in mild breeding years, when two offspring left the broods. Sex related differences in the recruitment of a local population of tawny owls are discussed with a focus on environmental effects.

We explored the population systems of Pelophylax esculentus at the southern border of the distribution range for this complex. We used both morphological data and allozyme markers to describe population systems in this region. All three taxa in the complex, P. ridibundus, P. lessonae and their hybridogenetic form, P. kl. esculentus occurred in the research area. In four localities that were analysed near the Danube River, we found complex population systems of both the parent species and their hybridogenetic form. Southward from the border defined by the Sava and Danube riverbanks, only the P. ridibundus — P. kl. esculentus (R-E) system was detected. Among these R-E populations, the abundance of the hybridogenetic form declines sharply from the north to the south. The most common and widespread system in Central Europe, the P. lessonae — P. kl. esculentus population system, was detected in only one locality near the Sava River.

Food composition of otter, Lutra lutra, was studied by the analysis of 349 spraints found during one year period (2003–2004) at the River Kamenice (Czech Republic), where Atlantic salmon, Salmo salar, fry have been stocked regularly since 1998 in a reintroduction programme for the species. Brown trout, Salmo trutta m. fario, dominated otter diet and formed 29% of all prey items and 62% of biomass of all fish eaten. The second most abundant prey (27%) was common sculpin, Cottus gobio, followed by Atlantic salmon, and grayling, Thymallus thymallus. The proportion of salmon in the diet of otters amounted to 14.5% in numerical abundance of all prey items taken and 2% in biomass of fish component of the diet. The majority (71.5%) of fish eaten by otters had a total length between 61 to 200 mm.

Predictions of stream landscape theory were tested with common agency fishery data in watersheds heavily fragmented by dams and barriers; large stream fragments support higher species diversity, more abundant populations, and a greater range of fish sizes. Study watersheds discharge to the Hudson River in New York USA, drain rocky and high relief landscapes, and have numerous mill dams and stream barriers. Stream fragments with fish collections ranged from 0.3 km to 119 km in contiguous length. Larger stream fragments had more diverse fish communities but not higher fish densities nor a wider range of fish sizes. However, almost all large stream fragments were supporting reproduction and rearing of the dominant stream species (brown trout Salmo trutta, brook trout Salvelinus fontinalis) while small fragments had no evidence of providing this fish community support. Therefore, consistent with the fundamental basis of stream landscape theory, large stream networks provide support for more species and more secure populations. The study supports the concept that diverse fish communities and secure populations benefit from access to a wide range of stream habitats.

Microhabitat use in the endangered cyprinid species spirlin Alburnoides bipunctatus and accompanying species was examined in three water courses of Slovakia to determine the species' environmental requirements as a basis for informing conservation policy and management. In all three rivers, water velocity, water depth and substratum character were central features of spirlin microhabitat use, regardless of year or season of sampling, with only limited variation in microhabitat associations as a function of time of day. Clear differences in microhabitat use and intra-specific associations during development were observed in two of the rivers. In particular, a shift in velocity preference towards faster flowing waters appears characteristic of spirlin during their larval and juvenile development, and possibly also that of gudgeon Gobio gobio, European minnow Phoxinus phoxinus, and chub Leuciscus cephalus, which are all species that may be significantly associated with young spirlin. Disproportionate use of deeper waters tended to increase with age in spirlin, and in gudgeon and barbel Barbus barbus, but spirlin preference for substratum was less uniform, with affinities ranging from indifference to strong preference. This contrasts the clear preferences for sand in gudgeon and for cobbles in European bullhead Cottus gobio. Of particular importance to young-of-the-year (YOY) spirlin are lentic zones with some sort of ligneous debris — habitat also used by YOY gudgeon and minnow. Contrary to previous reports elsewhere, spirlin did not avoid in-stream vegetation where present, and in one river it was preferred by YOY and 1 spirlin. To avoid declines in spirlin and accompanying stream-dwelling species, such as reported elsewhere in Europe, river management in water courses such as these should be limited to the rehabilitation of regulated sections to achieve a natural, heterogeneous channel character.

This study describes the reproductive behaviour of silver bream, Blicca bjoerkna, in an aquarium environment with hormonal injection, constant temperature and natural photoperiod conditions. The results revealed that the reproductive behaviour of silver bream was polyandrous with courting tactics including a high level of tactile stimulation and following behaviour developed by the males, but without territorial or aggressive acts. The individual participation of males in mating acts showed a significant positive correlation with the individual participation of males in following a female. A successful spawning act included trembling movements and violent splashing while eggs and sperm were released on plants. The female mated with one to five males without an active inter- and intra-sexual selection.