More than 3000 mammals were captured and translocated during a rescue operation conducted in French Guiana during the filling of a hydroelectric dam, a unique opportunity to gather biological data on many aspects of the Guianan fauna. All animals were identified, anaesthetized, measured, and biological samples (blood, skin biopsies) were collected and preserved. This study presents morphological data on all captured mammals belonging to 40 species of Marsupialia, Xenarthra, Primates, Carnivora, Artiodactyla, Rodentia and Sirenia. Data reported here include weight, shoulder height, head and body, tail, hind foot, head, and ear lengths, and some additional measurements for particular species. Some species were found to be larger than previously reported, which may be attributed to the large sample size, circumstances of data collection or to geographic variations. Such basic data appear to be hardly available on neotropical mammals, and thus provide useful comparative material for further studies.

Macquarie Island is the southernmost limit to the distribution of the black rat Rattus rattus. The species was introduced to this subantarctic island by sealers during the 19th century. The rats are now widespread and abundant in coastal areas all around the island. The distribution of rat populations is divided into discrete units by the availability of suitable habitat which, in turn, is a consequence of the rugged topography, particularly on the west coast. Rats are found from almost sea level to 200–250 m a.s.l. and up to 1 km inland. They have adapted successfully to the rigorous climate and firmly occupy a habitat niche in an environment where food is plentiful, predators are few and interspecific competition minimal. The principal habitat, tall Poa foliosa tussock grassland, provides year-round shelter and food. Rats dig burrows in the peaty stools of the tussock plants and construct nesting chambers at the base of the dense leaf canopy. Predictably, this provides a warmer and more stable thermal environment than that experienced outside under the tussock canopy where the runs are located. Tussock grasslands are spreading under the influence of management control measures directed at the introduced European rabbit and possibly global warming. Management programmes are also directed towards the eradication of feral cats. In response, rat populations may be expected to expand in numbers and to occupy new territories. Without control this may, in the long term, have serious consequences for the island's avifauna, particularly the smaller, burrow-nesting species.

At one nursery roost of Leisler's bat Nyctalus leisleri, the first bat often, and over half of the colony exceptionally, left before sunset. Departure was earlier during the period of lactation, when energy demands were highest. Consequently emergence data had to be standardized to allow for this before investigating possible associations with light intensity and meteorological factors. The importance of such standardization in general is emphasized. Emergence was earlier on overcast nights and was delayed with increased light intensity. The bats in a neighbouring roost, from which fewer data were obtained, also left earlier on overcast evenings, but departure was generally later than in the first roost, and there was no evidence of its being earlier during lactation. These differences between the roosts may be at least partially explained by the difference in size of the exit holes. At both roosts departure was mainly as a series of outbursts, and this was more marked during the first half of emergence. Rate of emergence increased with colony size. It was unusual for the first bat to leave more than 30 min, or for any bat to leave over 60 min, after sunset. Heavy rain inhibited or disrupted emergence.

Four species of the genus Hippopodina Levinsen, 1909 are described from material originally attributed to Hippopodina feegeensis (Busk, 1884). The type species Lepralia feegeensis is redescribed and three further species of Hippopodina are recognized: H. pulcherrima (Canu & Bassler, 1928), H. iririkiensis sp. nov. and H. viriosa sp. nov.

Chelodina rugosa is a fast-growing, carnivorous turtle that occupies seasonally ephemeral habitats, whereas Elseya dentata is relatively slow-growing, largely herbivorous and confined to permanent water. Ovarian cycles followed an annual cycle of enlargement beginning in December (E. dentata) and January (C. rugosa), followed by ovulation and then follicular regression. Nesting season was determined from presence of gravid females, and for C. rugosa spans some 8 months from the late wet season until mid dry season, during which the turtle lays multiple clutches of eggs in underwater nests. Nesting may continue for longer when waterholes dry later following prolonged wet season rains. Nesting by E. dentata also begins in the late wet season but is complete by May and only one clutch is laid. Females of both species reproduce each year and clutch size and mass are related to female size. Annual spermatogenic cycles are similar in timing to those reported for temperate-zone chelids but would be classified as pre-nuptial because spermatogenesis begins before breeding. Gonial proliferation begins at the start of the wet season and spermiation coincides with the onset of ovulation. Mating was not observed but in C. rugosa probably occurs during December and January soon after turtles emerge from aestivation. Post-mating storage of sperm in the epididymes did not occur in E. denatata but did appear to occur in some C. rugosa. The high reproductive output and extended nesting season of C. rugosa reflects its occupation of highly productive but unpredictable habitats and a reproductive strategy which ensures that some hatchlings meet optimal conditions for emergence. In contrast, the comparatively low fecundity and short nesting season of E. dentata, despite year-round warm temperatures and access to permanent water, suggests that its reproductive output may be energetically limited by a largely herbivorous protein-poor diet.

We report on the first established case of identical twinning in birds. The occurrence, genetic identity and subsequent development of identical emu (Dromaius novaehollandiae) twins is described, and comparisons drawn with single chicks hatched in the same season. The twin-bearing egg, significantly larger than any other egg in the same clutch, was artificially incubated and hatching assistance was necessary. At hatching the female twins were small, but their combined weight approximated that of a single chick from an egg of equivalent weight, and by 18 months of age they were near average in size. DNA analysis of blood collected from the twins showed a complete match with 22 bands per sample larger than 3.8 kb. The estimated probability of this occurring by chance was 1.0×10-13 in two unrelated emu and 1.0×10-6 in siblings, indicating a high probability that the twins were identical.

Seasonal migration pattern and home range of radio-collared roe deer (Capreolus capreolus) were studied in Lier, Norway, an area with a steep altitudinal gradient and a low population density of deer. Roe deer conformed to the usual pattern of temperate cervids with migration to low elevations during winter. Summer home-range size increased with increasing altitude, and only a small proportion of individuals had home ranges at high altitudes. It is concluded that these high elevation areas were probably of low quality. Time of spring migration was later in deer with a high elevation summer range. A lower frequency of females (30.0%) than males (61.5%) was stationary, and more females (30.0%) than males (0%) were long distance migrators (> 10 km). This supports an earlier hypothesis that migration patterns of roe deer are also influenced by social factors.

We considered the problem of conserving small populations of prey by reviewing observational and field experiments in search of general answers to the question of how predators impact upon their prey. We then explored the likely effectiveness of predator control as a conservation tool by simulating a small, fragmented population of prey. We chose red grouse in Britain as an example of this general predicament. An individual-based population simulation model was used to simulate the fate of a small red grouse population. The model was used to investigate the relative impacts of predation, habitat changes and stochastic factors associated with small population size on the viability of the population. Although most predator–prey studies have been undertaken in temperate regions and only four studies found evidence of regulation, some generalizations arose. Predation can limit populations but generally did not drive the prey population to extinction. Extinction was more likely in cases involving an introduced predator on islands or in isolated prey populations. The simulation model showed that at small population sizes the stochastic factors were always significant, whereas environmental variation and habitat change had the greatest impact on large populations over the long term; predation was only a significant threatening factor when it occurred at a high rate, was more severe over the long term when predators took a constant proportion of the prey base, and when predation was across all age classes.

A 3 year study of the diets of breeding royal Eudyptes schlegeli and rockhopper E. chrysocome penguins was carried out at two nearby colonies on Macquarie Island. Diets of both species were dominated by euphausiids and myctophid fish, in particular Euphausia vallentini and Krefftichthys anderssoni. Prey items were those found in the region of the Polar Frontal Zone, confirming the importance of this zone to these penguins. Diets of both species before hatching of the chicks were variable between years, and differences in quantity of food brought ashore and degree of digestion of prey suggested inter-annual variation in distribution of prey resources. No dietary differences were detected in either penguin species across the breeding season, which reflected variability in diet at all stages, indicating that individual penguins foraged in separate areas. Significant differences between the two species were found, royal penguins consuming more myctophid fish and rockhopper penguins consuming more euphausiids. Differences were also found in the size class of prey items taken and the degree of digestion of food by both penguin species, indicating that prey were taken from different sectors of the ocean. It is concluded that the overlap in diet is small in individuals from these two spatially close colonies and, contrary to previous studies, indicates a separation in the resources used by both species. The contrast with previous studies is most likely a reflection of the different methods used to assess overlap and, to a lesser extent, the years and colonies in which the comparisons were made.

New data on the morphology of Salticella fasciata immature stages are given from stereo scanning microscope observations. Distinctive features are presented for the egg chorion and the main sensorial structures of the cephalic, thoracic and abdominal segments of the larvae. In contrast to previous studies, the presence of float hairs on the posterior disc is clearly observed in the three larval instars. The ecological and phyletic significance of some characters are discussed.

This study investigates how habitat variation affects sett density, the number of animals per social group and group territory size in the badger (Meles meles). Identical methods were applied in three habitat types: lowland parkland with mixed woodland, pastoral farmland and upland rough pasture with moorland, representing areas of presumed good, medium and poor badger habitat, respectively. Contiguous main setts were identified and bait-marking was used to estimate territory size. Group size was estimated by direct enumeration. Variation in sett density, group size and territory size supported the hypothesis that badger group and territory size are influenced by habitat type. This was further supported by analyses of data from other studies in the British Isles. The implications for badger spatial ecology, badger survey techniques and the badger's role in the epidemiology of TB are discussed.