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The breeding population of cormorants Phalacrocorax carbo sinensis has expanded more than twenty-fold in continental Europe since 1970, and these large piscivorous birds cause conflicts with human fishery interests in large parts of Europe, including areas outside their breeding range. Culling aimed at reducing local population size takes place in some wintering areas, particularly in France and Switzerland. The effectiveness of such management actions is unknown and depends on how high cormorant site fidelity is. We use winter resightings from the period 1980–2000 of 24,000 cormorants colour-ringed in Denmark and The Netherlands to estimate site fidelity. Year-to-year fidelity to single sites (typically lakes) was 85–90%. For cormorants that changed site mean distances moved from year to year were typically between 10 and 50 km, depending on geographical location. However, long-distance movements (maximum observed was 1,891 km) also occurred regularly. For larger parts of the winter range, exemplified by France, about 3% of all birds left the area from year to year. A mathematical model showed that the observed levels of movement among wintering areas were sufficiently high to sustain a wintering population in France at levels of culling which would drive it to extinction in the absence of immigration. Although cormorants are not nomadic outside the breeding season, as previously believed, site fidelity is sufficiently low and movement among wintering areas sufficiently high that it must be taken into account in management programmes.
A total of 62 mitochondrial haplotypes were detected from 174 samples of hazel grouse Bonasa bonasia from Hokkaido, Primorskii, Sakhalin, Magadan, Siberia and Bohemia using 428 bp of the mitochondrial DNA control region. Haplotype diversity for four populations in Hokkaido was more than 0.8, suggesting that a reasonable population size had been maintained throughout their history. Haplotypes from Hokkaido and haplotypes from Primorskii were clearly separated from other Eurasian continent haplotypes, not only in the phylogenetic tree but also in the network tree. Haplotypes from Hokkaido, Sakhalin and Magadan radiated from the hypothetical root composed of a double cubic network of parallel substitutions. Most of the haplotypes were separated by three substitutions from the root, or within a maximum of five substitutions. Pairwise sequence differences for most Eurasian haplotypes had a bimodal curve consisting of the first peak at 0–1 substitution differences and the second peak at 3–4 substitution differences, whereas those for Hokkaido haplotypes had only a peak at around 4–6 substitution differences. These observations most likely indicate that the populations analysed were differentiated about 40,000 years ago, and have expanded to the present distribution during the climatic optimum over the last 10,000 years.
In this study we sought to determine main predictors of the body condition of hen pheasants Phasianus colchicus in Great Britain. We collected a total of 181 hen pheasants from 21 estates throughout Britain in 1996 and 1997. Pheasants collected from shooting estates which undertook spring supplementary feeding had significantly larger fat reserves than pheasants collected from estates where supplementary feeding stopped at the end of the shooting season (1 February). Hens from estates managed for wild pheasants had larger fat reserves than hens from estates managed for reared pheasants. However, there was no difference in parasite loads of Heterakis gallinarum, Capillaria sp. or Syngamus trachea between pheasants from wild and reared estates, and parasite load did not influence body condition. Our results suggest that food availability is a key factor influencing body condition of hen pheasants in Britain. We recommend that game managers provide supplementary grain in breeding territories through the spring to increase food availability and maintain pheasant body condition.
Distribution of the Siberian flying squirrel Pteromys volans in northern Finland, at the edge of its global range, is fairly distinctive: the species is apparently absent in the western part of the region (Pohjanmaa), occurs regularly in the central part (Koillismaa), and only sporadically further east closer to the Russian border (northern Kainuu). In this study, we examined landscape structure in these three regions using geographic information system (GIS) and multi-source land use and cover data to identify key characteristics in landscape structure that are linked to the observed distribution pattern of the Siberian flying squirrel in northern Finland. We analysed landscape structure by studying habitat type proportions in nature reserves and in large-scale landscape samples within the regions. In addition, landscape configuration and connectivity were analysed within larger landscape sample plots. Our results suggest that the observed distribution pattern is associated with natural patterns in landscape structure at local and regional scales. Open peat lands, bogs and non-forested habitats dominate the landscape in the western part of the region and possibly account for the absence of the Siberian flying squirrel. More subtle differences between the central and eastern parts of the region indicate regional scale landscape responses of the species. The relatively high amount of spruce-dominated mixed forests in the central part was associated with the regular occurrence of the Siberian flying squirrel, whereas the increasing dominance of pine forests towards the east was associated with the low number of sightings. Forest management history is much alike in the different parts of the region, but the effects of forest management on the actual range of the species cannot be estimated owing to a lack of knowledge on accurate population trends in northern Finland. However, human-caused fragmentation and large-scale habitat degradation may have long-term effects on the persistence of the species in northern Finland.
Quantifying the abundance of small mustelids is important both for conservation purposes and for our understanding of ecosystem processes. Footprint tunnel tracking is one of the techniques now used to index the relative abundance of small mammals; however, there have been few or no previous attempts to calibrate indices of mustelid abundance derived from footprint tunnel tracking. Weasel Mustela nivalis abundance was assessed by footprint tunnel tracking and simultaneous live-trapping, either capture-mark-recapture or removal, in six sites in northern England from April 1998 to February 2000. The number of tunnels with weasel footprints was tightly related to the number of weasels live-trapped, although, as expected, the relationship varied with field vole Microtus agrestis density and season. Temperature had only a weak effect in the calibration. The same number of tunnels with weasel footprints was equivalent to greater weasel abundance at high vole density than at low vole density. Similarly, weasel abundance was greater for the same number of tunnels with weasel footprints in summer and autumn than in winter and spring. In conclusion, it is important to correct for variation in vole density when using activity indices such as footprint tunnel tracking to sample weasel abundance, otherwise spurious patterns may emerge from the use of such index data.
Using radio telemetry, we examined within home range habitat selection by the Eurasian pine marten Martes martes (11 males and eight females; 1,495 locations) in managed forest in two study areas, the Varaldskogen Wildlife Research Area, Norway, and the Grimso Wildlife Research Area, Sweden, near the southern limit of the boreal forest zone. Pine martens preferred spruce-dominated forest with large (≥20 m tall) trees and avoided clearcuts and open habitats. Males and females used similar habitats and habitat use was little influenced by year, season and activity mode (active vs inactive). When habitat types were ranked in order of use, stands dominated by large spruce trees were preferentially selected over the lowest-ranked habitats, i.e. pine-dominated stands with trees <20 m tall, clearcuts, open areas and deciduous stands, but were used similar to other spruce-dominated categories and pine-dominated stands ≥20 m tall. Although pine martens exhibited selection and avoidance of certain habitat types, they were able to exploit a wide range of successional stages in forests with a long history of exploitation.
Counts of reproductive units, i.e. family groups, constitute the main monitoring index for lynx Lynx lynx populations in Scandinavia. However, for some purposes it is necessary to extrapolate from the number of family groups to obtain an estimate of total population size. Using data on survival and reproduction from radio-marked lynx from three Scandinavian study areas, we simulated the lynx population structure in February. The average proportions of family groups out of all independent individuals, i.e. adults and yearlings, in these simulations were 21% ± 2.1 (SD), 22% ± 3.6 and 27% ±3.1 for the data sets from northern Sweden (Sarek), southeastern Norway (Hedmark) and south-central Sweden (Bergslagen), respectively, and the overall mean for all three study areas was 23% ± 3.8. This translated into extrapolation factors of 6.14 ± 0.44,6.24 ± 0.73 and 5.48 ± 0.40 for the three study areas, respectively, leading to an overall mean for all three study areas of 5.95 ± 0.64. We conclude, that it is possible to extrapolate from the number of family groups to obtain an estimate of total lynx population size with a statistical measure of uncertainty.
Three long-finned pilot whales Globicephala melas were equipped with satellite-linked time-depth recorders on the Faroe Islands on 15 July 2000. The purpose was to study the diving behaviour and habitat use of free-ranging pilot whales in the northeast Atlantic. Summarised data on the diving behaviour of the whales were collected for up to 129 6-hour periods. The maximum depth of dives was 828 m and the mean number of dives below 12 m was 12.2/hour (SD = 8.2). On average, the whales spent 60% of their time above 7 m depth. All three whales had significantly longer surface times when they were outside the continental shelf than when they were on the shelf. The mean vertical speeds ranged from 0.9 m/second for dives to 150 m to 2.3 m/second for dives to 600 m. No dives below 12 m lasted longer than 18 minutes, and more than 60% of dives lasted less than three minutes. The mean number of dives that lasted less than one minute was significantly higher in offshore areas than on the continental slope for all three whales. Compared to other odontocetes of similar size, long-finned pilot whales apparendy either have a lower dive capacity or utilise a niche in the water column that requires less diving activity.
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