Most Australian birds do not migrate over long distances and therefore have to cope with seasonal changes in weather and food availability. We investigated whether the small (11 g) silvereye Zosterops lateralis changes its thermal tolerance from winter to summer. Body mass and body temperature of silvereyes exhibited little seasonal variability. However, metabolic rates (MR) and thermal conductance showed significant changes. Below the thermoneutral zone (TNZ), winter-acclimatized birds had significantly lower resting MR and thermal conductance than summer-acclimatized birds. Within the TNZ (˜27.0–33.6 °C winter; ˜25.4–33.5 °C summer) basal MR of winter-acclimatized birds (2.30 ± 0.29 mL O2 g-1 h-1) was significantly lower than that of summer-acclimatized birds (2.88 ± 0.43 mL O2 g-1 h-1). The average daily MR also differed significantly between summer and winter largely due to a greater reduction of MR at night and the decreased conductance. Our study shows that small passerines such as silvereyes exhibit seasonal variability in physiology and thermal energetics, even when they live in areas with a relatively mild climate, to help overcome seasonal changes in weather conditions and food availability.

We report on the geographic and temporal variation in pup condition in 20 colonies of New Zealand fur seals Arctocephalus forsteri around South Island, New Zealand during three consecutive breeding seasons, 1996–98 (n = 6856 pups) and provide hypotheses to explain the observed patterns. Three alternative data combinations are presented to calculate pup condition from body measurements and identify which combination seems to be best suited for analysing geographic patterns. A morphometric index of pup condition was best estimated by comparing all pups in all years using least-squares linear regression of the loge-transformed measurements of length vs mass. Condition varied significantly among years and colonies, but not between sexes. We also estimated seasonal changes in pup densities at colonies and investigated the relationship between pup density and condition. Mean pup densities among colonies ranged from 4.94 to 7.46 pups/100 m2 (summer) and from 4.99 to 7.04 pups/100 m2 (winter) from 1996–98, and differences between summer and winter densities varied with year. Pup density explained a significant proportion of the variation in pup condition in 1996 and 1998, suggesting that condition is partly density-dependent. After accounting for the effect of density, we found geographic differences in pup condition, and we offer alternative hypotheses to explain these differences. We also show that the 1998 El Niño coincided with a reduction in pup condition. A morphometric index of pup condition seems to be useful as an indicator of spatial and temporal variation in the marine environment.

This paper describes the mate locating strategies of male Australian carpenter bees Xylocopa (Lestis) aeratus Smith and X.(L.) bombylans (F.). Males of X. aeratus display three different mate locating strategies: (1) non-territorial patrolling near nests or flowers; (2) territorial defence of nests that contain unmated females; (3) non-resource territoriality (hill-topping). At the onset of the mating season, non-territorial patrolling and territorial defence of nests were observed in three out of four populations that were studied, while in a fourth population only non-resource territoriality was observed. Later in the mating season both territorial defence of nests and non-resource territoriality were observed in one of the populations. Male X. bombylans have only been observed using the non-resource territoriality. Males of all size classes used the same strategy at any one time, but males that were observed more than once in a territory were significantly larger, suggesting that larger males have greater territory-holding capacity. Upon encountering males, receptive female X. aeratus alternated low zigzag flights through the vegetation with high-velocity flights well above the vegetation, while males followed closely. This behaviour is interpreted as a test of the flight capacity of males, and is indicative of pronounced female choice. The mate locating strategies of the two species are compared with literature data from other xylocopine bees, and factors that might affect the choice of a particular mate locating strategy are briefly discussed.

A new species of Eudendrium from the Chafarinas Islands (south-western Mediterranean) is described. The distinctive character of this species is its association with symbiotic zooxanthellae, a feature in common with Myrionema, the only other genus of the family Eudendriidae. The evolutionary implications of this similarity are discussed. A review of the Mediterranean species of Eudendriidae is presented, including data on the cnidome when available, biological data from the material studied, and a key to identify the Mediterranean species.

The extent to which anti-predator mobbing can be modified in response to new predators was investigated by examining the response of terns (Sterna hirundo and S. paradisaea) and gulls (Larus fuscus, L. argentatus and L. canus) to introduced mink Mustela vison, native otter Lutra lutra and rabbit Oryctolagus cuniculus models in areas inhabited by mink and areas uninhabited by mink. Gulls and terns typically flock over predators of adult birds (a fleeing response), whilst diving at predators of chicks and eggs (an attacking response). Terns in mink-inhabited areas flocked over a model of a mink, but did not dive at it as much as they dived at otter and rabbit models. A stronger fleeing rather than attacking response suggests that adult terns perceive mink as a threat to themselves as well as to their chicks and eggs. Gulls, in comparison, dived at the mink model, indicating that mink are not perceived as a threat to the adults of these considerably larger species. Both gulls and terns showed a much lower level of response to mink in mink-free areas, suggesting that the type and extent of mobbing is altered through experience with predators and the level of risk associated with mobbing the predator.

Numerous field studies have attempted to assess competition between ungulates through the analysis of resource overlap. However, interpreting the results of these studies has been problematic because low overlap may be the outcome of historical competition and high overlap will result in competition only when that resource becomes limiting. In New Zealand, increasing densities of introduced Himalayan tahr Hemitragus jemlahicus have competitively excluded introduced Alpine chamois Rupicapra rupicapra, but where densities of tahr have been reduced the two species can coexist. This study evaluated the role of habitat selection in the coexistence of these two recently sympatric ungulates in Carneys Creek, eastern Southern Alps, New Zealand. Seasonal habitat selection was estimated by observing unmarked male tahr, female tahr and chamois monthly for 25 months. The proportional availability of six habitats (grassland, grass bluff, rock bluff, shrubland, scree and snow) was measured from aerial photographs taken in each of the four seasons. Although the null hypothesis that tahr and chamois select habitats similarly was rejected in three of four seasons, there was high overlap in preference for grassland and shrubland, and avoidance of scree and snow. Tahr were more often observed in grass bluff and rock bluff than were chamois. Overlap in habitat selection was greatest during winter when snow dominated the landscape, reducing the availability of vegetated habitats. Using Hurlbert's statistic, the niche breadth of chamois was significantly smaller than that of tahr in all seasons except autumn, in which they were similar. These results, together with anecdotal evidence from Carneys Creek, suggest that chamois increase their habitat specialization in the presence of tahr. Although differences in habitat selection are likely to have contributed to the coexistence of chamois with tahr, even relatively small increases in tahr density in some seasons could be expected to exclude chamois from some habitats in Carneys Creek.

Northern tuatara Sphenodon punctatus punctatus survive on about 26 islands off the north-east coast of the North Island, New Zealand. These rare, lizard-like reptiles include seabirds in their diet. The presence of the Pacific rat Rattus exulans on some islands has been implicated in the decline of tuatara populations through predation and competition for food. Pacific rats and tuatara eat similar dietary items, including seabirds. Seabirds have high levels of the long chain n-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The potential contribution of seabirds to the diet of tuatara was investigated by measuring the composition of plasma fatty acids and the concentrations of triacylglycerol and cholesterol of adult tuatara from Green Island (rat-free, numerous seabirds) and Coppermine Island (rat-inhabited, relatively few seabirds). The composition of plasma fatty acids differed between islands and sexes. Specifically, tuatara from rat-free Green Island had higher levels of the long chain PUFAs arachidonic acid, EPA and DHA compared to tuatara on rat-inhabited Coppermine Island, and males had significantly higher levels of DHA than females on both islands. Concentrations of plasma triacylglycerol and cholesterol were higher in tuatara from Green Island than Coppermine Island. Males had higher cholesterol but lower triacylglycerol concentrations than females. Differences in fatty acid composition and lipid concentrations between groups of tuatara imply differences in diet. Tuatara on the rat-free island evidently had a higher intake of n-3 PUFAs compared with tuatara on the rat-inhabited island. This is probably due to higher seabird consumption, or perhaps to the presence of other dietary items containing EPA and DHA. High concentrations of plasma triacylglycerol and cholesterol may be the result of a high intake of insect larvae. We recommend the direct investigation of the diets of northern tuatara and the consequences of differences in the composition of plasma fatty acids for reproduction.

The gut contents of a female specimen of Graneledone cf. boreopacifica collected from the caldera wall of Axial Volcano, near an active hydrothermal vent in the Northeast Pacific Ocean are reported. At least 30 individual gastropods and 46 individual polychaetes are represented in the gut contents by hard parts. Shell fragments and shells removed from the gut allow ready identification of the gastropods Provanna variabilis and Lepetodrilus fucensis, both of which are known only from North Pacific hydrothermal vents. Jaws of polychaete worms are identified as those of the nereidid, Nereis piscesae, and the predatory polynoids, Levensteiniella kincaidi and an unidentified species in the subfamily Branchinotogluminae. Not only was a considerable volume of prey hard parts ingested, the gastropod shells had been crushed before being ingested. The large size of the beaks in this genus of octopus and the increased area they offer for insertion of the superior mandible muscle, the prime mover in beak closure, support the hypothesis that these beaks exert sufficient force to crush the gastropod shells. Although cephalopods had been reported to be absent from hydrothermal vents, the data presented here demonstrate that not only do they occur in vent habitats, they actively prey on vent fauna.

The mouse-like marsupial Antechinus agilis is common to south-eastern Australia with breeding and life-history traits being highly synchronous. Mating activity is confined to a 10- to 15-day period in August, at the end of which all males die as a result of a stress-induced suppression of the immune system. Ovulation occurs at this time and females rely on stored sperm from specialized crypts in the lower isthmus of the oviduct for successful fertilization. Here we report a high incidence of mixed paternity litters, which can be attributed to sperm from multiple males being stored in the isthmic crypts. Data from this study also suggest a possible second male siring advantage in controlled ex situ sperm competition mating trials, irrespective of the delay between the two males being given mating access to the female or of the mating time relative to ovulation. In determining paternity through DNA profiling, population genetic data were obtained that showed significant differences in the genetic heterozygosity between unrelated adults, half siblings and full siblings. We suggest that the isthmic crypts, in addition to storing viable sperm, are capable of releasing a mix of sperm that increases the likelihood of mixed paternity litters. This allows all mating males the opportunity to sire young, increases female reproductive fitness and overall maintains high levels of population genetic heterozygosity in the face of total male mortality annually.

The foraging behaviour of Cape clawless otters Aonyx capensis was investigated. Factors included: duration of dives, recovery times, processing times, hunting success, per cent time at the surface, and time foraging before each catch. Observations were made during the day on solitary adult A. capensis in a marine environment in False Bay, South Africa. There were significant differences in duration of unsuccessful dives, recovery times, and processing times as well as successful dives with various depths. Aonyx capensis prefer hunting at depths of 0.5–1.5 m. This is despite having a higher hunting success, catching larger, more energy-rich prey (fish), and shortest time foraging per catch, at depths of 1.5–2.5 m. Some of the data presented support the optimal breathing hypothesis, which predicts that both surface and dive times should increase for dives of greater depths. However, diving efficiency does not decrease with increasing depth, and percentage time at the surface does not increase with increasing depth. These are contrary to the optimal breathing hypothesis.

Tadpole development was compared in three amphibian species (Bufo calamita, B. bufo and Rana temporaria) that suffer different risks of pond desiccation in nature. Using a replicated pond system, development was monitored in desiccating and non-desiccating ponds, and in vertical-sided and gently shelving (’shoreline’) ponds. In desiccating ponds, tadpoles suffered from crowding effects and metamorphosed at a smaller size, but development was not accelerated in response to desiccation in any of the three species. Desiccating ponds had higher maximum temperatures but also lower minimum temperatures, which may explain the lack of any difference in development time between desiccating and non-desiccating ponds. Although shoreline ponds were slightly warmer than vertical-sided ponds, development under these conditions was also consistent with a crowding, rather than a temperature, effect. In shoreline ponds, metamorphosis generally took longer, was less synchronized between individuals, and resulted in a smaller size at metamorphosis, compared to development in vertical-sided ponds. The lack of species-by-desiccation interactions indicated that there were no differences between the three species in developmental plasticity. Developmental constraints may place a limit on the degree of plasticity that can evolve in a species such as B. calamita, which breeds only in ephemeral ponds with a variable hydroperiod. Alternatively, low genetic variability within British populations of B. calamita may have constrained the evolution of adaptive plasticity in this species.

Data gathered from the Ministry of Agriculture, Fisheries and Food (MAFF) National Rabbit Survey sites in the 1980s showed substantial site-to-site and year-to-year variation in rabbit Oryctolagus cuniculus abundance. Data on physical and biological factors from 450 sites were collected to seek explanations for this variation. The rabbit abundance index on the 2.25 km transects (walked along the edge of fields, woods, hedges, etc.) was used as the dependent variable for multiple regression and principal components analyses. Additionally, a preliminary attempt at mapping rabbit abundance and distribution in England and Wales using a GIS system was made. Each of the analyses produced a list of the important variables enhancing or reducing rabbit indices. Common to each list were aspects of woodland – area, number of pieces and length of edge; the dryness and patchiness of soils on site; rainfall in late winter, or variables associated with wetness of soil (e.g. number of days with rain, altitude). Other important variables included predator removal policy and the site location nationally. The two strongest components, woodland parameters and predator removal policy, are under human influence. The effects of region, county and year were small, but year-to-year variation within sites was larger, suggesting that rabbit populations were reacting markedly to unmeasured variables, e.g. myxomatosis outbreaks. The analysis provides a useful explanation of the factors that affect rabbit populations and a basis for how these factors may be manipulated.

Recent theoretical papers on temperature-dependent sex determination in reptiles are based on the assumption that crocodilian populations, particularly adults, are markedly female biased. While there is evidence that some crocodile populations may conform to this expectation, there is no compelling evidence that American alligator populations are female biased anywhere in the species' range. Previous data had indicated that some populations of juvenile and/or adult alligators were significantly male biased. However, these studies were criticized for sampling errors. Adult males typically occupy a different habitat from that of females, and males frequent areas where they are more likely to be caught. In contrast, in juveniles, both sexes occupy the same habitat. We determined the sex ratios of c. 3000 juvenile alligators collected from 11 sites over 6 years in south Louisiana. Our results indicate a significant sex bias (58% male), but variation was evident among samples. Sex ratios varied by year and site, and the interaction of these factors was significant. At one site in one year, there was a female bias (71%), but in no year was there an overall female bias across sites. From this study and earlier reports, we conclude that there is no evidence at present of female-biased sex ratios in the juvenile and/or adult alligator populations, and consequently, that certain models of temperature-dependent sex determination in reptiles require re-evaluation. Furthermore, our data suggest a pattern of differential mortality of females vs males during the first years of life, a pattern consistent with a key prediction of several differential fitness models for the adaptive significance of temperature-dependent sex determination in reptiles.

Mitochondrial DNA sequences consisting of 645 sites from the 12S rRNA and 16S rRNA genes were used to estimate the phylogeny of 15 of the 32 species of spiny-footed lizards Acanthodactylus. The resultant tree has similarities to that produced from a differentially weighted data set of 32 morphological characters but there are also significant differences. However, combined analysis of molecular and morphological data sets produces the same tree topology as DNA sequence alone. The molecular data confirm that there are distinct eastern and western clades within Acanthodactylus, but place A. boskianus in the former while the A. scutellatus group constitutes a third clade. Species for which only morphological information is available were integrated with the combined tree to give a provisional phylogeny for 31 species. This phylogeny indicates that the ancestor of existing Acanthodactylus probably originated in south-west Asia and that North Africa was invaded by more than one lineage of the genus. It also suggests that soft aeolian sand habitats may have been independently occupied more than once. Molecular data provide independent evidence that the differential weighting of morphological characters in past analyses was appropriate.

There is a vast literature on the reproductive behaviour of cichlid fishes, most of which describes spawning strategies and parental care. However, descriptive information on the early development of cichlids is scarce. In this study, embryos and larvae of laboratory-reared Cichlasoma dimerus are described. The early ontogeny is documented from oocyte activation until the beginning of the juvenile period. At a water temperature of 25 ± 0.5 °C and a 12:12 h photoperiod, cleavage is finished in 10 h and the first somites appear at 26 h of development. The larvae hatch during the beginning of the third day and are deposited by both parents in a pit they have dug out in advance. Yolk-sac larvae present three pairs of adhesive glands over the head, these transient larval organs being characteristic of substrate-brooding cichlids. After another 5 days, the fry swim freely and begin to feed exogenously. Since the yolk-sac is not completely reabsorbed until 2 or 3 days later, there is a period of combined endogenous and exogenous food supply. The juvenile stage is reached on the 42nd day from spawning.

It has been postulated that the variation in an animal's body temperature during different phases of bone deposition can be estimated from the variation in the ratio of two oxygen isotopes in phosphate recovered from its fossil. Using data from a fossil Tyrannosaurus rex skeleton, the previous researchers failed to reject the null hypothesis that the variation found in bones from the body core is significantly less than that found in the extremities; they also failed to reject the null hypothesis that the coldest and hottest parts of the body differed by less than 4 °C. This suggests that either both null hypotheses are true, or that they are false but the statistical tests used were not powerful enough to detect this. Here I use calculation of confidence intervals to differentiate between these two alternatives. In the first case, I find that the data are consistent with the variance in both the core and the extremity being up to 2.5 times that of the other. In the second case, I show that observations are consistent with temperature differences ranging from 2.6 °C to 6.4 °C. Hence, neither case provides any real support for the hypothesis that bone deposition in this specimen occurred under essentially thermostable conditions.

In iteroparous organisms, maximum lifetime reproductive success is achieved through multiple successful breeding attempts. Therefore one of an individual's major life-history decisions is the allocation of resources between current and future reproduction. We studied the production of foetuses in the introduced female Canadian beaver Castor canadensis in Finland in 1992–93. The number of foetuses produced in 1993 was negatively correlated with the number produced in the previous year, irrespective of female age. Females that bred only in 1993 tended to produce more foetuses in that year than females that had reproduced in both years. However, the total number of foetuses produced was higher in females that had young in both years, stressing the importance of multiple breeding attempts in maximizing lifetime reproductive success. Despite the small size of the founder population in Finland, mean litter size and pregnancy rates were not different from North American populations.

The diet of 789 stoats Mustela erminea and 458 weasels M. nivalis collected in Great Britain between 1995 and 1997 is described from analyses of their gut contents. As a percentage frequency of occurrence, stoat diet consisted of 65% lagomorphs, 16% small rodents and 17% birds and birds' eggs. Weasel diet consisted of 25% lagomorphs, 68% small rodents, mainly Microtus agrestis, and 5% birds and birds' eggs. Male stoats ate a greater proportion of lagomorphs than females, which ate more small rodents. No differences in diet between the sexes of the weasels were detected. The proportion of lagomorphs in the diet of both species was greatest in the spring. Both species ate more lagomorphs in the 1990s than in the 1960s as a result of increasing rabbit populations following recovery from myxomatosis. The importance of small rodents had decreased for stoats and increased for weasels. Both species had a dietary niche that was more specialized than in the 1960s. The implications of these findings for stoat and weasel conservation are discussed.

An analysis of forelimb and hindlimb skeletal morphology of 15 passerine genera was performed to investigate the likely existence of an ecomorphological pattern relating morphology to migratory behaviour. Each genus was represented by a pair of species, one being sedentary and another migrant. Using a phylogenetic comparative method we found migrant species having longer sternum, deeper keel and longer coracoids than non-migrant species. Hindlimb morphology was not related to migration. These results are interpreted as adaptations for migrants favouring flight ability, as the larger the sternum and the coracoids the greater the surface available for attachment of the main muscles involved in active flight.

Genetic variation and the allozymic relationships of five families comprising 23 species of hystricognath rodents were examined using electrophoretic data from 19 presumptive gene loci. Direct-count heterozygosity ranged from 0% to 13.6%, and polymorphism varied from 0% to 36.8%. Fixed allele differences were instrumental for the segregation of taxa as summarized by the Distance Wagner procedure and by majority-rule consensus trees. The monophyly of the Octodontidae, and the family rank of the Abrocomidae and Ctenomyidae is supported by the data. Monotypic Myocastor coypus is not resolved as a distinct family but appeared within the Caviidae. Within the Octodontidae, paraphyly was detected in polytypic Octodon, whereas a high bootstrap value supported the node containing the desert specialists O. mimax (2n = 56) and Tympanoctomys barreare (2n = 102). The implications of allozymic data as a robust phylogenetic signal that connected biochemical associations to the prediction of tetraploidy in T. barrerae are discussed.