There are two microchiropteran bat species in New Zealand: the long-tailed bat Chalinolobus tuberculatus and the short-tailed bat Mystacina tuberculata. Both species coexist on Little Barrier Island in the Hauraki Gulf, New Zealand. In this study we examined the diet of M. tuberculata, and the activity levels of both bat species associated with Metrosideros excelsa, a native flowering plant and potential nectar source, on Little Barrier Island. Between November 1994 and February 1996, M. tuberculata were caught in mist-nets, and their faecal pellets were collected for later dietary analysis. In addition, pollen samples were collected from the fur of bats caught during December 1995 and January 1996. Faecal analysis showed that M. tuberculata on Little Barrier Island exhibits a high degree of omnivory, with its diet comprising flying and non-flying arthropods, and also pollen and other plant material. During December 1995 and January 1996, the activity levels of both bat species associated with flowering and non-flowering M. excelsa trees were investigated by recording bat echolocation calls with automatic detecting and recording units. Significantly higher numbers of M. tuberculata echolocation calls were recorded near flowering M. excelsa trees than near non-flowering ones, whereas the numbers of C. tuberculatus calls did not differ significantly between flowering and non-flowering trees. These results contribute further to the existing evidence for nectarivory in M. tuberculata.

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.

The distribution of play behaviour among the Australian marsupial families was surveyed. The rate of play in each species observed was categorized on a three-point scale: 1 – no play observed or reported; 2 – play rudimentary; 3 – play common. Common play occurred in the larger-bodied Dasyuridae, in Myrmecobiius, in Vombatidae, and in all Macropodoidea. In all other marsupials, play was rudimentary or absent. Categorical rate of play was not correlated with body mass or with metabolic rate but was correlated with relative brain mass. The distribution of play in Australian marsupials supported the hypothesis that play acts to modify brain development.

A total of 263 individual badgers Meles meles provided 718 blood samples which were screened for parasites. This revealed that 77.2% of individuals tested positive for Babesia missirolii at least once over 3 years, whereas 7.7% did so for Trypanosoma pestanai. However, the prevalence was highest in younger age classes, except in 1990 when it was high in most categories. There was some evidence that following a positive test for Babesia badgers were more likely to be caught again in subsequent years when compared to individuals testing negative. For Trypanosoma, although prevalence decreased from a peak of 29.2% from June onwards in 1990, we found no significant corollaries of infection. These results are discussed in the light of inter-annual variation in weather and other factors.

Distances at which jumping spiders (Salticidae) use optical cues to distinguish between prey insects and conspecific rivals were investigated using adult males of 37 species. During tests, salticids walked up a ramp toward a mirror or toward an insect enclosed in a transparent petri dish. All species directed threat displays toward their own mirror images and the displays were comparable to each species' typical behaviour during male–male interactions. The salticids never displayed in tests with insects at the top of the ramp. The virtual distances at which the spiders displayed are interpreted as an indication of the distances at which each species can distinguish rivals from prey. Representative species were from the subfamilies Lyssomaninae, Spartaeinae and Salticinae. Discrimination distances relate well to the foveal layer I receptor mosaics of the anterior median eyes for the three subfamilies. Compared with the salticines, the lyssomanines and, except for Portia, the spartaeines tended to have shorter discrimination distances. Portia spp. had discrimination distances comparable to the longest recorded for the salticines. The longest discrimination distances found were for the salticine Mogrus neglectus (max. 320 mm or 42 body lengths) and for the spartaeine Portia fimbriata (280 mm or 47 body lengths).

The bare-tailed woolly opossum, Caluromys philander, and the kinkajou, Potos flavus, are two syntopic neotropical nocturnal, arboreal and frugivorous mammals. Because of close ecology but great difference in size (weight 300 vs 3000 g), they represent pertinent models to examine the influence of size on foraging strategy. These species were studied by radio-tracking and direct observation during 22 months in a tropical forest in French Guiana. Both mammals’ foraging strategies with regard to flowers and fruits are characterized as follows: (1) numerous plant families and species are exploited; (2) most plant species are selected according to their abundance; (3) diet selectivity and diversity are similar in both mammals; (4) relative parts of flowers and fruits in the diet vary according to their year-long availability; (5) the choice of fruiting species is not related to the morphological type, size, or nutritious quality of fruits but instead depends on easy access to the edible part; (6) the length of foraging bouts is correlated with production for the most frequently exploited tree species; (7) feeding bouts are shorter in P. flavus than in C. philander; (8) P. flavus exploits large, highly productive canopy trees, while C. philander also visits canopy trees with low production and understorey trees. In conclusion, both mammals are opportunistic flower- and fruit-eaters, but the larger species (P. flavus) exploits larger, more scattered food patches, while the smaller one (C. philander) also exploits smaller, more numerous and more evenly distributed food patches.

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.

A primate community was studied in a fluvial tropical rain forest island, in the northernmost part of Brazilian Amazonia, in the State of Roraima. Density and biomass were determined, and the differences between the forest types were assessed. The line-transect method was used from the east towards the centre of the island. No previous studies had been carried out in this remote undisturbed area. Density and biomass varied between the forest types, as well as between frugivorous primates; the smaller-bodied species were more abundant in the forest that was richer in fruiting trees, while they were absent from a monodominant forest. The folivorous, or partly folivorous, primates were abundant in those forests with less fruiting trees. The abundance of the primates in the different forest types was shown to be a function of food availability.

The vasculature and the air ways of the lung of the sandboa Eryx colubrinus were cast using latex rubber, corroded, and studied with a scanning electron microscope to determine the shape, topographic configurations, and relative sizes of the gas exchange components. The sandboa had a right lung and a vestigeal left one. The lung, which terminated close to the anus, consisted of two distinctive anatomical regions. The exchange tissue was located in the cranial half of the lung while the caudal one consisted of a transparent avascular ‘air sac’. The right pulmonary artery, which was found on the laterodorsal aspect of the lung, gave rise to branches which supplied blood to the pleura and the faveolar septal walls. The geometric relationship between the flow of the venous blood (from the pulmonary artery) into the parenchymal zone of the lung and the convective/diffusive outwards air flow from the central air duct into the parenchyma is essentially counter-current: the air moves centrifugally and the blood centripetally. However, the arrangement between the air flow in central air duct and that of the venous blood is cross-current (i.e. the two media run in directions perpendicular to each other). These architectural schemes are similar to those that have developed in the avian lung. In fact, in its simplest form, the parenchymal region of the snake's lung corresponds with a single tertiary bronchus (parabronchus) of a bird lung. Further investigations are necessary to identify the factors that enforced this morphological convergence and to verify whether these congruent features are analogous, as they would seem to be, or from a phylogenetic perspective possibly homologous.

Foot areas of a wide range of kangaroos, wallabies and rat-kangaroos were measured from fresh material and museum specimens. The areas of the plantar pads scaled according to the predictions of geometric similarity. The terminal claw areas of digits IV and V scaled with a lower than predicted exponent, reflecting functional demands of different species. The pressure that these marsupials exert on the ground during quiet standing is proportional to (body weight)0.35, and is considerably lower than those exerted by ungulates. Hopping kangaroos exert pressures proportional to (body weight)0.37. The pressures exerted by medium and large macropods are comparable to those of galloping ungulates. The findings support the commonly held belief that introduced grazing animals may cause greater mechanical disruption of the soil surface, leading to increased rates of soil erosion, than Australia's indigenous grazing fauna.

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.

Faecal analysis was used to study the diet of great bustards in north-west Spain on a monthly basis for 1 year. After correction for differential digestibility, the diet composition by dry weight varied from 48.4% green plant material, 40.9% invertebrates and 10.6% seeds in August, to consisting almost completely of green plant material between December and March. At least 65 plant species were represented in the green plant material, but most occurred rarely and the bulk of this portion of the diet consisted of alfalfa. Eight invertebrate orders were detected in the faeces, of which Coleoptera, Hymenoptera and Orthoptera were most important by numbers. From August to November when seeds were important by dry weight, wheat and barley seeds were found in more faecal pellets than other species. Estimates of use and abundance were obtained to evaluate diet selection in the green plant material and invertebrate components. Alfalfa was strongly selected throughout the year, but grasses were used less often than expected. Coleoptera were always eaten in greater numbers than expected, Orthoptera were used either in proportion to abundance or less often than expected, and Hymenoptera less often in May, more often in September and November, and as expected at other times. The results support the suggestion that increasing alfalfa cultivation would be a useful management tool for maintaining endangered great bustard populations, but further work on the cost-effectiveness of this option is needed.

Bone mineralization and bone geometry at femoral midshaft were analysed for 33 muskoxen Ovibos moschatus ranging in age from 3 weeks to 4.5 years and in body mass from 9 to 215 kg, to assess changing mechanical properties associated with postnatal ontogeny. Analysis of the mineral density of bone (BMD) indicates little or no change in femoral mineralization until after 4 months of age. Between 4 and 6 months of age BMD increases markedly, and complete mineralization occurs by about 18 months of age. Femoral length (L) and bone strength (as measured by Z, the section modulus) scale negatively allometric with body mass (L ∞ M0.26 and Z ∞ M0.88) indicating that neonate muskoxen have longer and stronger femora for their body size than do older animals. When the neonate data were excluded, however, bone length and bone strength regressed against body mass did not differ significantly from isometry (L ∞ M0.32 and Z ∞ M1.03), implying that different growth trajectories characterize postnatal ontogeny before and after 4 months of age. As a consequence of the timing of ontogenetic changes in bone mineralization and cross-sectional geometry, safety factors calculated for the femur (derived from estimates of peak bending stress and fracture strength) are largest and smallest in neonates and 4-month-old calves, respectively. It is hypothesized that increased bone mineralization and accompanying diaphyseal stiffness after 4 months of age are necessary to maintain structural integrity of the femur.

The golden-faced saki monkey Pithecia pithecia chrysocephala (Cebidae, Primates) was observed eating soil from termite nests during a long-term study of a family group in a Central Amazonian forest fragment. In this paper we describe the behaviour involved in the geophagy in these monkeys, and the results of geochemical and physical analyses of the termite nest material, as well as root mat and topsoil samples below the trees, in order to clarify the possible reasons for it. The sakis ate soil from nine arboreal termite nests on 26 soil feeding-bouts (in 853 observation hours); 25 soil feeding-bouts occurred in March 1987 (rainy season), during 19 days or 132 observation hours, and occupied 0.7% of the feeding time. Geophagy frequencies did not differ between sexes (17 feeding-bouts of four females and 8 for two males). Mineral composition was higher in arboreal termitaria than in the topsoil. Kaolinite was the major clay component. Tannin adsorptive capacity, tested through a modified radial diffusion method of Hagerman, was around 10–20%, similar to a control with kaolin (10–20%), but lower than bentonite or celite (30–45%). The observations reported here, although inconclusive as to the function of geophagy in this species, indicate that it is not a mineral supplement during times of scarcity or high consumption of leaves, as has been reported for other primates, nor that it is related to fruit consumption (redressing possible mineral imbalance), as has been suggested for some other frugivorous mammals. Our results do not rule out tannin adsorptive hypothesis for the ingestion of clays, but, being an irregular habit, we argue that it is most likely related to rare and occasional dietary components.

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.

Using radio-telemetry, short-term cycles of activity, with a period of about 3 h, were detected in Orkney voles Microtus arvalis orcadensis and in one short-eared owl Asio flammeus, their principal predator. Visual observations showed that owls from four adjacent nests had similar activity patterns. These cycles tended to be synchronous both within and between the two species. Short-eared owls thus appeared to be foraging optimally by timing their hunting to coincide with peaks in vole activity, i.e. at times of maximum potential yield. The extent of diurnal activity in short-eared owls varied seasonally. Daytime activity was conspicuous for only a short period in spring and early summer. Otherwise owls were almost exclusively nocturnal. These seasonal changes in activity were probably a response to variations in vole diurnality, vole population size and daylength. Harassment and kleptoparasitism may have been additional influences that interacted with these seasonal factors to determine the extent of preferred nocturnal hunting. In addition, it is possible that the energetic constraints of breeding may force owls to hunt during daylight. Were males only to hunt at night then they may not be able to provide enough food for their mate and young at a time when nights are short and vole populations are only starting to increase.

With both a ‘manageable’ number of taxa and moderate levels of behavioural diversity, plethodontid salamanders of the North American subfamily Desmognathinae offer exciting opportunities for a phyloethological study of courtship. In moving toward this goal, the present paper reports courtship descriptions for two taxa with very different biologies: the pygmy salamander Desmognathus wrighti and the blackbelly salamander D. quadramaculatus. Despite similarities in behaviour patterns used to accomplish indirect sperm transfer by means of the deposition of spermatophores on the substrate (tail-straddle walk), these two taxa greatly differ in the ways by which males stimulate, or ‘persuade’, females to mate. Male D. wrighti bite and seize their partners in order to provide them with tactile and chemical stimuli. In contrast, male D. quadramaculatus provide these same stimuli, but by head rubbing and snapping. I end with a comparative survey of courtship in the Desmognathinae, and a first attempt to interpret behavioural evolution in the subfamily using a phyloethological analysis.

In this study we explored quantitatively the relationships between the size of bats, the frequencies in their echolocation calls, and the incidence of moths and beetles in their diets. We focused on the predictions of the allotonic frequency hypothesis which states that some insectivorous bats increase their access to moths that can hear echolocation calls by shifting to frequencies to which the ears of these insects are less sensitive. The hypothesis predicts that the frequencies dominating the echolocation calls of bats may be correlated with the incidence of moths in their diets. We collected data for 62 species of bats that take airborne prey, usually flying insects, 25 species of high duty cycle echolocating bats (Rhinolophidae and Hipposideridae) and 37 species that are low duty cycle echolocators (Vespertilionidae and Molossidae). For bats whose echolocation calls are dominated by frequencies < 100 kHz our regression analyses showed a parabolic dependency between moth consumption (% volume or % frequency) and echolocation call frequency (kHz), supporting the allotonic frequency hypothesis. The use of echolocation calls dominated by frequencies outside the range of best hearing by moths may indeed increase the availability of these insects to the bats. However, when the same analysis was performed with only the bat species using echolocation calls dominated by sounds > 100 kHz, the relationship was not statistically significant, suggesting that morphological characteristics rather than echolocation call frequency may limit the range of potential prey items. Our analyses also demonstrate the importance of jaw morphology as a predictor of the incidence of beetles or moths in the diets of bats, and reveal that generally bigger species (as defined by forearm length) use echolocation calls dominated by lower frequencies than smaller species. In both high duty and low duty cycle echolocating bats the relationship between body size and dominant call frequency was best described by a linear model. We also propose that perch hunting was central in the development of the high duty cycle approach to echolocation.

In a recent paper Raxworthy & Nussbaum (1995) included the Madagascan dwarf chameleons Brookesia peyrierasiand B. tuberculata in the synonymy of B. minima, regarding known hemipenial differences between B. tuberculata and B. peyrierasi as artefacts. Our studies demonstrate that the hemipenis description of B. tuberculata by Brygoo & Domergue (1975) was largely correct and referred to unusual but real structures. The enormous differences in the hemipenis morphology of B. tuberculata (hemipenes of six specimens examined) and B. peyrierasi (hemipenes of five specimens examined) strongly suggest that they are not conspecific. Furthermore, morphological differences in the arrangement of head crests and expression of supraocular spines were noted between these two taxa and B. minima. The differentiation of the three taxa is furthermore corroborated by both univariate and multivariate analyses of morphometric data. We therefore propose to consider Brookesia minima, B. peyrierasi, and B. tuberculata as distinct species. This conclusion corroborates the validity of biogeographic regions as suggested from the analysis of distribution patterns of other Brookesia species.

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.