<p> Dragonflies (Odonata: Epiprocta) and damselflies (Odonata: Zygoptera) are a conspicuous aspect of the biota in ponds on southcentral Alaska's Copper River Delta (CRD). Odonate densities, secondary production, and diets were assessed in sixteen ponds classified by delta region (east vs. west) and landscape type (outwash plain (OP) vs uplifted marsh (UM)). </p><p> <i>Enallagma boreale</i> (Coenagrionidae) comprised 48.5% of collected odonates. <i>Leucorrhinia hudsonica</i> (Libellulidae) and <i>Aeshna juncea</i> (Aeshnidae) comprised 36.6% and 10.4% of collected odonates, respectively. <i>L. hudsonica</i> densities and secondary production were significantly higher (p&lt;0.001) in west UM ponds than in other pond types. Ostracods (Ostracoda) and water boatmen (Corixidae) dominated west OP <i>A. juncea</i> diets. Midge larvae (Chironomidae) dominated <i>A. juncea</i> diets in remaining pond types, occurring in 68% of foreguts. 27% of <i>A. juncea</i> foreguts demonstrated intraguild predation, and 6% of foreguts demonstrated cannibalism. Foreguts containing threespine stickleback (<i>Gasterosteus aculeatus</i>) revealed <i>A. juncea's</i> apex predator role in CRD ponds.</p>

No description available.

This study aimed to assess the impact of pine marten (<I>Martes martes</I>) predation on red squirrels (<I>Sciurus vulgaris</I>) in Scotland. Red squirrel density, range use and habitat selection were compared at two study sites: Novar, where pine martens were present, and Learney, where they were absent. At Novar there was a lower density of squirrels than at Learney. Habitat selection at Novar was greater than at Learney with squirrels preferring Scot pine (<I>Pinus sylvestris</I>) and avoiding sitka spruce (<I>Picea sitchenis</I>). At Learney, no selection was shown and with squirrels using all habitats, including sitka spruce, in proportion to their availability. Pine marten diet was assessed from the analysis of 1938 scats at the Novar study site. Red squirrels comprised 0.6% of estimated weight intake in pine marten diet; in relation to the density of squirrels at the study site this represented a high proportion of the population. The field vole (<I>Microtus agrestis</I>) was the most important species in the diet. Pine marten habitat use was assessed by radio tracking. This revealed that martens avoided non-forest habitats and used broad-leaved woodland in greater proportion than it was available. There was overlap in the home ranges of pine martens and red squirrels and martens hunted in all habitat classes used by squirrels. In addition, the habitat used most frequently by pine martens (pole stage coniferous woodland) also had the greatest proportion of squirrel dreys present. Analysis of drey use at the two study sites did not show any evidence of squirrels adjusting their behaviour in the presence of pine martens. In contrast to what was expected, squirrels at Learney used a significantly greater number of dreys, which were more concealed than at Novar. At Learney drey characteristics could not explain drey use, whereas at Nova drey use was positively related to dreys that were in smaller trees with high canopy contact, and a high density of surrounding trees. It was suggested that this was due to fewer suitable trees being present at Novar whereas at Learney there were more spruces present which provided better cover and concealment for dreys. The density of red squirrels was assessed at several forests throughout Scotland, using counts of cones eaten by squirrels, and was then related to the length of time pine martens had been present. Forests where martens had been present for more than 10 years had a significantly lower density of red squirrels than either areas where martens had been present for less than 10 years or where martens were absent. There differences were independent of any variation in the availability of cones and the habitat of the forests surveyed. Using records from the Forestry Commission squirrel questionnaires, changes in the distribution of red squirrels over a 20 year period were related to the presence and absence of pine martens, and also to changes in the distribution of martens. Red squirrels were present in a smaller proportion of 10 km squares in areas where martens were present than where they were absent. There was also a greater proportion of losses and fewer colonisation of red squirrels in areas where martens were present.

The distribution, social structure, epidermal lesions and population size of the bottlenose dolphin population in the Moray Firth off the coast of Scotland were studied between 1990 and 1993. Dolphins were seen in the inner Moray Firth all year round: numbers were low in winter by rose in late spring to peak in summer. All parts of the inner Moray Firth were frequented, but three areas, at narrows which had deep water and strong currents, were favoured. Areas used by the dolphins varied seasonally: in winter the outer parts of the inner Moray Firth were occupied, whilst in summer all areas were used. The spring increase in numbers and changes in distribution occurred together as part of a general redistribution of individuals (demonstrated using photo-identification methods) in the inner Moray Firth. Animals entering the inner Moray Firth from outside stayed further towards the open sea than previously resident animals. Seasonal migrations of fish, elevated temperatures and sheltered waters may explain the summer increase in use, whilst social factors between groupings may have maintained the horizontal separation of different segments of the dolphin population. Individuals ranged widely (average range 123 km²) and rapid, long distance movements, across the Moray Firth, were observed (190 km in 120 hrs). The dolphins were highly social, with 99% being seen in schools. These ranged in size from 2 to 46 individuals (median 4.5). School sizes were not unusual compared with other populations. They were found to be bigger in winter and in more open sea environments. Average levels of social cohesion between individuals were low. Close bonds occurred only between females and their calves and lasted for at least four years after birth. Each female loosely associated with a network of other females. The associates of each female remained similar over at least three years and were the result of preferential associations rather than coincident ranges.

Previous ringing studies of the brown long-eared bat (<I>Plecotus auritus</I>) in Britain suggest adults of both sexes are associated with the same summer colonies for many years, with at least some natal roost philopatry in both sexes. Detected movements among colonies are negligible. The aim of this study was to use molecular genetic markers to determine the levels of genetic relatedness within a colony, the levels of gene flow among colonies and the mating system. Six polymorphic microsatellite loci were isolated from a <I>P. auritus </I>genomic DNA library, and used to screen 666 <I>P. auritus</I> individuals from 26 colonies in north east Scotland. Paternity exclusions established that approximately a third of allocated paternities involved males from the same summer colony, although many females mate with males from roosts within 5 to 10 km. No skew in male reproductive success was identified, probably due to the inability of males to defend females throughout their oestrus. Mean levels of relatedness among all colony members was low, due mainly to extra-colony mating and low reproductive skew. Genetic differentiation among roosts was also low; but significant, and genetic isolation by distance was identified across the study area. Two highly divergent mtDNA lineages were identified within the population, which diverged by 1.9% at the 12S rRNA gene, suggesting a historically large population. The observed distribution of mtDNA haplotypes in the population may reflect past fission and fusion events in <I>P. auritus </I>colonies. Results from nuclear DNA markers support the occurrence of natal philopatry in both sexes, and suggest that <I>P. auritus </I>summer colonies should be regarded as separate sub-populations. However, each colony is reliant on others close by for mating, and genes move throughout the population via a stepping stone model. This species is therefore vulnerable to colony destruction and habitat fragmentation.

Studies of the behavioural ecology of young harbour seals were made in the Moray Firth, NE Scotland. The terrestrial behaviour of mothers and pups were recorded at an intertidal haul-out site, using scan and focal-animal sampling. A large percentage of the seals' time was spent resting and suckling. Suckling was influenced by tidal state with peaks at the beginning and end of haul-out. Suckling sessions were shorter for younger pups but overall time spent suckling did not differ with age. Pups became increasingly responsible for maintaining the suckling relationship and pair proximity as lactation progressed. A rapid, non-invasive method of distinguishing seals in their first year from older age classes were determined, based on mean hair widths. Mean hair widths feel into two distinct groups, and were significantly greater for older age classes. The diving behaviour and foraging distribution of juvenile seals was compared with that of older animals. Dive duration was positively correlated with body size and time at the surface was negatively correlated with size. Most dives fell within theoretical aerobic dive limits. Body size restrictions on diving performance were predicted to limit the bottom time and dive depth of juveniles compared to adults. Whilst the foraging locations of juveniles overlapped with those of adults, juveniles, unlike adults, did not forage in water greater than 40 m in depth. Juveniles exhibited a marked shift in foraging area use, apparently in response to an influx of overwintering clupeids. Growth in length and weight during the first year of the life was linear. Males were longer and heavier than females during this period, but grew at the same rate. Between-year changes in food availability led to increased length and weight of yearlings. Mean lengths of adults were lower than those of other populations, although growth rates were amongst the highest.

The aim of this study was to investigate the ecology and behaviour of the serotine bat, a widely distributed and little studied European species. The composition and social structure of maternity colonies were determined during three breeding seasons. No adult males were found in any maternity colonies. A total of 209 adult females were caught and 71 individuals were recaptured in the same and/or subsequent years. Only one female was reproductively active in all three years. Of all females caught, 66% were reproductively active and 34% were reproductively inactive. Twelve percent of the females caught were nulliparous. A total of 87 juvenile bats were caught. Births took place between the 29 June and the 6 July. There was a significant difference in body size between juvenile male and female bats and also in the body size of juveniles caught at different roosts at the same time of year. Activity patterns at a maternity roost were investigated by use of a remote monitoring system throughout a summer season. The activity patterns were unimodal during early pregnancy, bimodal during middle and late pregnancy and multimodal during lactation. The duration of the first flight decreased significantly during pregnancy as the parturition date approached and increased significantly as lactation progressed. Inclement weather inhibited or shortened the duration of flights. At weaning mothers sometimes used different day-roosts from their young. The behaviour of foraging serotines was investigated by radio-tracking. Reproductively active females were strongly philopatric to their day-roost and reproductively inactive females sometimes changed their day-roosts, moving up to 5 km. There was no movement of individuals between maternity colonies. White streetlamps were often used by foraging serotines and they were commonly found feeding close to accumulations of cattle dung in late summer. Foraging serotines were able to locate temporary concentrations of insects and they used three distinct foraging styles: hawking, flycatching and feeding on the ground.

This thesis considers the role of the fox as a scavenger and predator, the management and performance of hill sheep, methods of controlling foxes and their effectiveness, and trends in fox populations. Sheep carrion was abundant in April and May on two study areas, but scarce in July-August and January-February. It predominated in the food of foxes during the first half-year, but field voles were more important in the second half. Fluctuations in numbers of foxes were associated with vole peeks, but carrion may support more foxes than could otherwise subsist on the scanty live prey. Foxes killed about 1% of the estimated lamb crop during three years but 2% in a year when foxes were numerous. Golden eagles killed up to 1% of the lamb crop. Both predators killed lambs aged 1-5 days, in good condition with aieauate fat reserves. More foxes were killed each winter from 1973-74 to 1976-77 on twenty-five estates throughout Scotland but the number or breeding dens remained the same. It follows that killing foxes in winter, as widely practised, is ineffective in reducing the breeding population. Dens were not randomly spaced. They were commonest on agricultural land and fewest in deer forest. No known change in land use or control methods can account for the increase in foxes in Scotland during the last thirty years. New methods of controlling foxes, such as aversion therapy or chemosterilants, are unlikely to appear within the next few years. Meantime an improvement in the management of hill sheep is more likely to increase the production of lambs than bigger efforts to kill foxes.

No description available.

The octopodid species, <I>Pareledone turqueti</I> and <I>Pareledone polymorpha</I> are caught in research and commercial trawls on the shelf around South Georgia. Specimens from a survey in Cumberland Bay in 1987 and groundfish surveys in 1989, 1991 and 1994 were examined. Although superficially similar in appearance the species are discernible by differing hectocotylus and beak morphology. The hectocotylus is larger in <I>P. polymorpha </I> and is long and pointed with deep transverse grooves. <I>P. turqueti</I> has a short, blunt hectocotylus with a smooth inner surface. In <I>P. turqueti </I>the lower beak is large with a curved blunt hood, and in <I>P. polymorpha</I> the beak has a significantly smaller hood that is flat and pointed (P<0.001), with a slightly upturned rostral tip in small specimens. The size and shape of the radula also differs between species; it is broader with blunt teeth with a multicuspid rachidian tooth in <I>P. turqueti</I>, while in <I>P. polymorpha</I>, the radula is narrow with sharp teeth and a unicuspid rachidian tooth. There are also interspecific differences in the relative size of the posterior salivary glands and in the number of suckers on the arms, with <I>P. polymorpha</I> having larger salivary glands (P<0.001), and a higher number of suckers per arm (P < 0.001) than <I>P. turqueti</I>. These differences suggest that these sympatric species occupy discrete trophic niches. Crustacean and polychaete prey are important components in the diet of both species. Shelled bivalve and gastropod prey, present in 62 and 32 % of <I>P. turqueti</I> specimens, were absent from all <I>P. polymorpha</I>. The fecundity of both <I>P. turqueti</I> and <I>P. polymorpha </I>is low, with a mean of 52 developing eggs in mature <I>P. turqueti</I> and a significantly higher mean of 69 in <I>P. polymorpha</I> (P < 0.001). Mature eggs are large in both species, about 16 mm along the major axis, and have short stalks, suggesting that they are laid separately. In maturing females there is a bimodal distribution of egg length, possibly as a result of competition for space and nutrients within the ovary, which limits the maximum number of developing eggs as they increase in size. Several spent females were identified, indicating that they had laid the majority of their eggs. The poor condition of these females, suggests that <I>Pareledone</I> spp. are semelparous, with spawning occurring shortly before death. Spermatophores in both species are large, up to 70 mm long. Although <I>P. turqueti</I> and <I>P. polymorpha</I> have overlapping geographic ranges, a significant difference is observed between the mean depth distribution of the species. During the 1994 survey <I>P. polymorpha</I> had a mean depth of 211 m and <I>P. turqueti</I>, a mean depth of 157 m (P < 0.001).