Today it is sometimes forgotten how recently ecology and animal behaviour have emerged as respectable sciences from being merely glorified nature study. I can remember hearing, only half a century ago, a distinguished professor stating firmly at a meeting of the Society for Experimental Biology, I think it was, that ‘In Cambridge we do not teach ecology!’ The transition that has taken place in attitudes since those days owes much to people like Peter Jewell. With a background in agriculture and physiology, his decision in the early 1960s to take his skills out into the field, to attempt the elucidation of some of the many problems facing real animals in the real world, was an important shift of emphasis. He brought a grasp of physiological function, and concepts of experimental rigour learned in the laboratory, to subjects that had sometimes lacked these important values. The researches which followed, often carried out in collaboration with the many colleagues and students who were attracted by his philosophy and personality, were part of the growing stream of vigorous new ideas that have shaped present-day attitudes towards ecology and ecological research.

In this study we investigated the effect of rainfall on the home range (calculated over 90 days) of adult female Arabian oryx (Oryx leucoryx) in a reintroduced population in central Oman. We looked at response to rainfall for six rain events in the period June 1986 to January 1992; rainfall was localized on five occasions and on one occasion covered the study area. Response, in terms of range and core area, showed considerable variation between rainfall events, perhaps as a result of variation in ranging behaviour between individual oryx. However, in the first 90 days after localized rainfall the home range and core area of oryx outside rain areas increased before decreasing significantly 91–180 days after rain. In comparison, range and core area of oryx inside areas of localized rainfall either did not change or decreased after rainfall as animals took advantage of improved conditions locally rather than investigating grazing elsewhere. When rain fell over the whole study area, range size did not change, but there was an immediate increase in core area and a reduction in range overlap indicating movement to new areas. During extended drought very localized rainfall caused oryx to move quickly to areas of new rain and by 28 days 70% of all adult females had found fresh grazing. Thereafter numbers declined to around 30% by 225 days, before oryx again moved back into the new rain areas. We attributed this pattern of movement to changes in the nutritional quality, measured as crude protein, of available forage. Data for single animals revealed considerable individual variation in response to rainfall; some animals moved quickly to rain whilst others failed to reach it. This variation had consequences for reproductive success and survival and illustrated that, for the oryx, response to rainfall is a key to desert success.

The activity and distribution of the lysosomal marker enzyme acid phosphatase have been studied in the epidermis during tail regeneration in the lizard Podarcis muralis. This study gives information both on the mechanism of separation of the old from the new epidermal generation and on the involvement of lysosomes in β- and α-keratinization in lepidosaurians. The biochemical analysis shows that the activity of acid phosphatase was higher in the regenerating tail than in the normal tail until the stage of skin shedding at around 25–30 days post-amputation. The enzyme was present in keratinizing layers of epidermis, and particularly in the shedding layer. The shedding layer followed the outline of the regenerating scales beneath the wound in the epidermis showing that lysosomal enzymes are involved in epidermal shedding. The ultrastructural study showed that acid phosphatase was initially localized within the lysosomes but, with the progress of differentiation, it also appeared free within the cytoplasm of the cornifying cells of the shedding complex and of the β-keratinizing cells, and in the intercellular space among them. The role of lysosomal enzymes in the shedding process and their involvement in the mechanism of β-keratinization is discussed. While the process of β-keratinization has an intracellular and extracellular localization of acid phosphatase, the process of α-keratinization shows that most acid phosphatase is localized within the cell. Lysosomes and mesos granules containing acid phosphatase were concentrated in the cytoplasm of differentiating mesos cells. Some mesos granules later discharged their contents into the extracellular space. The α-layer was partially formed in proximal regenerated scales around 30 days post-amputation. Lysosomes appeared to concentrate within pre-keratinizing cells of the α-keratin layer and little reactivity was seen extracellularly.

This study investigates the effect of tooth sharpness on the force and energy necessary for a tooth to divide foods of differing physical properties. The material properties of foods are likely to affect the shape that is best to divide them. In order to test the effect of sharpness on a tooth's proficiency in dividing insect prey, experiments involving penetrating and driving through insect prey of differing physical properties were carried out using specially designed punches that varied in tip- and cusp-sharpness. A refinement of tooth measurements which are relevant to their effectiveness in penetrating and driving through food is expounded. ‘Tip-sharpness’ is defined as the radius of curvature at the tip of a cusp. ‘Cusp-sharpness’ is defined as the volume or surface area of the tooth per unit distance from the tip of a cusp. The experiments show that tooth shape is important in the force and energy needed for teeth to penetrate and drive through insects. Also, the scale of teeth is important – teeth of the same shape but different size vary in their effectiveness to divide foods.

Otters are classified in the Lutrinae and are united by a suite of semi-aquatic adaptations that distinguish them from the rest of the Mustelidae. Past systematic studies have been based primarily on overall similarity of morphological characters but have not been concordant, with regard either to relationships within the subfamily or to the relationships of the Lutrinae to other taxa in the Mustelidae. We evaluate the relationships among nine of the 13 species of otters and their position in the Mustelidae through phylogenetic analysis of the complete nucleotide sequence of the mitochondrial cytochrome b gene. Based on the sequence data presented here, our results suggest that otters are divided into three primary clades that include: (1) the North American river, neotropical and marine otters; (2) the sea, Eurasian, spotted-necked, cape clawless and small-clawed otters; and (3) the giant otter. Furthermore, our results indicate that among sampled mustelid taxa, members of the genus Mustela are most closely related to otters. The hierarchical relationships among clades are not well resolved, particularly the monophyly of otters, largely because a pattern of short internal branches combined with long terminal branches suggests a rapid evolutionary radiation. Estimates of divergence time calibrated by the fossil record suggest that the lineages leading to the North American river, neotropical and marine otters, and the giant otter diverged before the end of the Miocene, much earlier than predicted from the fossil record.

The diet of Leisler's bat Nyctalus leisleri was investigated by analysis of droppings collected from six mainly pastoral sites in Ireland, two sites in England (one mainly pastoral, one arable predominating) and three in Germany (in forest), and comprised mainly medium-sized and small insects caught in flight, many of which were probably from swarms. There was a major pastoral prey component, indicated mainly by Scathophaga stercoraria, Scarabaeoidea and associated Acari, at the Irish sites (estimated as 29–55%) and the English pastoral site (22%), but this was less significant elsewhere (1–12%). Insects with aquatic larvae (Ephemeroptera, Trichoptera, Chironomidae/Ceratopogonidae, Culicidae) often made up an important part of the diet (4–39%). Another distinct component, the Lepidoptera, Hemerobiidae, Chrysopidae and Ichneumonidae, which were all intercorrelated in the results, possibly indicates feeding near trees. This component was most important at the German (36–63%) and English arable (30%) locations, but of less significance at the English pastoral (11%) and Irish (2–19%, mean 6%) ones. The diets in Germany were otherwise diverse.

Net branchial sodium uptake, and net acid and ammonia excretion, together with gill ventilation volumes were measured in euryhaline European flounder Platichthys flesus, adapted to freshwater. External amiloride or acetazolamide (0.1 mmol l-1) caused significant reductions (P < 0.05) in sodium uptake and net acid excretion, while 0.05 mmol l-1 thiocyanate had no effect on any of the fluxes measured. Ethoxzolamide (0.1 mmol l-1) however, caused significant reductions in all fluxes measured and also caused a 32% reduction in the volume of water exhaled by the gills. In this study, it appears that sodium uptake and net acid excretion are indirectly linked, probably by a proton pump arrangement which is thought to be a mechanism for sodium uptake in trout gills.

Branchial sodium uptake, and net proton equivalent and ammonia excretion, together with isolated filament potentials were measured in euryhaline European flounder Platichthys flesus, adapted to freshwater. External benzamil (0.05 mmol l-1), a specific inhibitor of sodium conductive channels, caused significant reductions (P < 0.05) in sodium uptake and a marked decline in net proton equivalent excretion. In contrast, 0.05 mmol l-1 external 5-(N,N-dimethyl)-amiloride, a specific inhibitor of the Na+/H+ antiport, had no effect on any of the fluxes measured. The effect of vanadate, an inhibitor of H+-ATPases, was examined at two concentrations, 0.1 and 0.5 mmol l-1, and both caused significant reductions (P < 0.05) in sodium uptake and net proton equivalent excretion. Mean resting isolated gill filament potentials in freshwater-adapted P. flesus were found to be −23.8 ± 1.1 mV (inside negative) and became less negative in the presence of amiloride, an inhibitor of sodium transport. Using microelectrodes it was possible to measure two potentials in the filament: an apical potential and a transepithelial potential. The transepithelial potential was similar to that measured in vivo, while the apical potential, may be generated by the pavement epithelial cells. In this study, it appears that sodium uptake and net proton equivalent excretion are not strictly coupled but are indirectly linked probably by a proton pump arrangement, which is thought to be a mechanism for sodium uptake in trout gills. A possible role of the apical potential is discussed.

Popularity as a fur-bearing species led to the American mink Mustela vison being transported far beyond its native range in North America (Dunstone, 1993). In many places the species was bred in fur farms, from which there were inevitably escapes, and in some areas it was deliberately released in large numbers with the intention of establishing harvestable populations. Both routes led to the widespread establishment of feral populations of this versatile semi-aquatic mustelid. Invariably, close scrutiny of the impact of feral American mink on native fauna has led at least to concern, and increasingly to proof, that they are inimical to the conservation of native species. Evidence of the impact of the American mink on native species falls into two categories. First, American mink may reduce significantly, and locally exterminate, certain vertebrate prey (Macdonald et al., in press). Second, as versatile and seemingly aggressive competitors they may alter the competitive balance within the local guild of semi-aquatic predators, even ousting native mustelids.

The Andean hog-nosed skunk Conepatus chinga inhabits South America from Bolivia in the north to as far south as Neuquén province in Argentina (Redford & Eisenberg, 1992). In spite of its wide distribution and its value as a furbearer in Argentina (Fujita & Calvo, 1982), little is known about Andean hog-nosed skunk ecology, including its foods. It seems to forage solitarily during the night in open savannas and in arid and shrubby areas (Cabrera & Yepes, 1960; Mares et al., 1996), capturing arthropods (mainly beetles and arachnids) and occasionally small mammals and preying on eggs and fledgling birds (Cabrera & Yepes, 1960; Redford & Eisenberg, 1992; Mares et al., 1996). Here we present the first quantitative study on the diet of this species, based on the analysis of faeces collected during the summer season in two localities in Argentinean Patagonia.

When bats emerge from colonies to feed and drink their emergence patterns deviate systematically from those expected at random (Kunz, 1974; Swift, 1980; Bullock et al., 1987; Brigham & Fenton, 1986). In particular, many bats appear to group together as they emerge, and form into ‘clusters’ or ‘outbursts’ (but see McAney & Fairley, 1988; Kunz & Anthony, 1995 for exceptions). The function of this clustering behaviour has been the topic of recent debate, with some authors favouring the hypothesis that the behaviour is an artefact of large numbers of animals moving through a restricted space (Kalcounis & Brigham, 1994) and others suggesting the behaviour has a more significant biological function such as protection from predation (Leen & Novick, 1977; Speakman, Stone & Kerslake, 1995) or information transfer (Wilkinson, 1992).

This paper describes the denning behaviour of 24 feral ferrets Mustela furo on farmland, East Otago, South Island, New Zealand. One hundred and ninety seven dens were located and radio-collared ferrets were found to share dens simultaneously with other ferrets on 7.4% of 706 radio-tracking events and used dens that had been previously used by other ferrets (sequential den sharing) on 44.3% of occasions. In this particular study, ferrets were exhibiting a higher degree of sociality than has been recorded in other solitary mustelid species and therefore may not be adhering to the model of intrasexual territoriality thought to apply to other mustelid species. Den sharing may be a mechanism by which bovine tuberculosis Mycobacterium bovis is transmitted within ferret populations. Over 80% of the sequential den sharing occurred within 14 days, well within the survival span of M. bovis bacilli. Denning of infected ferrets in haybarns may pose a risk of transmission of M. bovis to livestock from hay.

The caching of fungi by red squirrels Sciurus vulgaris was investigated in commercial conifer plantations by walking transects in Kielder Forest, Cumbria and Wauchope Forest, Scotland. In 11 transects, a total of 58 fungal fruiting bodies were observed on branches in trees, consisting of four different species (49 Russula ochroleuca, seven R. metica, one R. vesca, one Colybia maculata). Fungal stores were found to be short lived and most fruiting bodies cached were gone after 2 weeks. Based on the survey findings we estimate that within an average red squirrel home range there would be a minimum of 42 cached fruiting bodies, constituting a food store of approx. 525–714 kJ.

The theoretically optimal shape of a bat's wing changes with flight mode (Norberg, 1987; Norberg & Rayner, 1987) and several studies have shown this theory to be largely born out in practise (Aldridge & Rautenbach, 1987; Norberg & Rayner, 1987; Crome & Richards, 1988). For instance, bats with wings of relatively low surface area (high wing loading) that are also relatively long and thin (high aspect ratio) tend to be fast, straight fliers spending most of their flying time foraging or commuting in open areas such as pasture or above the forest canopy (Norberg & Rayner, 1987). In such bats manoeuvrability is improved by the possession of small, pointed wing tips to reduce drag. In contrast bats with wings of relatively high surface area that are also relatively short and wide with large, rounded wing tips tend to be slow, highly manoeuvrable fliers foraging in cluttered habitats such as woodland (Norberg & Rayner, 1987).

In general, if populations are founded by very small numbers of individuals, low levels of genetic diversity amongst subsequent generations known as founder effects, can be predicted to occur as a result of genetic drift (Franklin, 1980; Lacy, 1997). A loss of genetic variation has been reported in several species that have experienced genetic bottlenecks because of habitat fragmentation, geographic isolation or inbreeding depression (Gilbert et al., 1990; Hoelzel & Dover, 1991; Ellegren et al., 1993; Timms et al., 1993; Wauters, Casale & Dhondt, 1994; Wauters, 1997). This loss of genetic diversity can have deleterious effects on reproductive output. For example, laboratory and captive breeding programmes provide extensive evidence of both decreased fecundity and reduced juvenile survival (Ralls & Ballon, 1982, 1986; Du Bois, Dhondt & Van Puijenbroek, 1990; Brock & White, 1992), and research conducted on natural populations of common shrews Sorex araneus has reported similar findings (Stockley et al., 1994). However, genetic evidence from some wild populations shows that highly inbred populations can survive and thrive despite low levels of genetic variability (Gilbert et al., 1990; Wayne et al., 1991; Ellegren et al., 1993). Grey squirrels Sciurus carolinensis, were introduced into Britain from eastern North America on several occasions between 1876 and 1910. Furthermore, between 1906 and 1937 grey squirrels were translocated to a variety of different locations within Britain (Middleton, 1931; Shorten, 1954). From the 1930s it rapidly expanded its range and is now ubiquitous to almost all of central and southern England, Wales and some lowland areas of Scotland (Lloyd, 1962, 1983; Gurnell &; Pepper, 1993). In view of this highly successful colonization by an invading species the grey squirrel appears to have been unaffected by any loss of genetic diversity as a result of recent population bottlenecks. We have used DNA fingerprinting (Jeffreys, Wilson & Thein, 1985a), a technique which provides a good indication of genome variability (Jeffreys et al., 1985b; Kuhnlein et al., 1990; Kunieda et al., 1993) to assess overall levels of genetic diversity in two British grey squirrel populations; Alice Holt Forest on the borders of Hampshire and Surrey in southern England and Thetford Forest in East Anglia.

Many nocturnal small- to medium-sized forest mammals can be surveyed only by directly sighting or hearing each individual. This is particularly so in tropical regions. Signs (footprints, dung scratch-marks, etc.) are often not identifiable to species (similar species frequently occur together); villagers' identifications are rarely clear enough for research purposes, and the provenance of specimens in markets can rarely be established to satisfactory precision. Assessments of animal status from brief surveys are becoming increasingly important for many conservation purposes. A repeatable methodology for field assessment of the status of nocturnal mammals is needed to allow comparisons, particularly between sites.

The impact of public rights of way on badger setts was examined in the Bradford area of West Yorkshire using comparisons of 38 setts surveyed in 1985–1996 and again in 1992–1993. Badger setts were compared on the basis of whether they were still in use or not, and on the number of illegal disturbance events recorded over the study period. The number of, and distance from, public accesses did not influence sett persistence, and the least frequently disturbed setts (i.e. those with an average of one or less disturbance incidents every 2 years) were closer to a larger number of accesses. Frequency of poaching was high near to heavily disturbed setts and those no longer occupied at the later survey. Less frequently disturbed setts were associated with landowners who were unsupportive of badger conservation: it is possible that such landowners are highly protective of their land and thus incidentally reduce the frequency of poaching and other forms of disturbance. Setts in areas with formal authorized shooting were less disturbed. Setts still in use tended to be in open habitats and visible from roads and nearby dwellings. Setts in open areas were less often disturbed than those in wooded sites. Since public access may not reduce sett persistence and may even be beneficial in an area of high wilful persecution, there are implications for the management of public access.

In spite of the studies carried out for several decades on Galemys pyrenaicus, no paper has specifically estimated desman densities, although indirect information can be inferred from the studies in the French Pyrenees on the use of space by Stone & Gorman (1985) and Stone (1987a).

On 3 September 1996, B. Neill, investigating the peculiar behaviour of three ravens, found them disputing over a freshly dead dolphin stranded on the shore at Bornish, South Uist, Western Isles, Scotland (National Grid ref: NF 721 300). Neither he nor M. Bones, who collected the skeleton, could immediately identify the dolphin, despite having seen most of the species recorded around the Western Isles, although we suggested that it might be an Atlantic white-sided dolphin Lagenorhynchus acutus with an aberrant colour pattern.

Tagged, captive-bred mountain gazelles were released into Hawtah Reserve, Saudi Arabia. More than 1 year after they were freed, their drinking behaviour at two water troughs was recorded for 2.5 months during late summer/autumn, using automatic cameras and monitors triggered when an infra-red beam was broken. Only 30% of gazelles (n = 40) were recorded drinking and only individuals which lived close to troughs drank. No gazelles visited the one natural water point. Among gazelles which lived close to the troughs, older individuals were more likely to drink than younger animals. The noise of the cameras as they took a photograph frightened some gazelles and may have influenced their frequency of drinking after they were photographed for the first time.