bluuebunny/crossref_metadata_2025 huggingface dataset:
Diet and nectarivorous foraging behaviour of the short‐tailed bat (Mystacina tuberculata)
Authors: Arkins A. M. , Winnington A. P. , Anderson S. , Clout M. N.
Published: February 2006

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.
Environmental determinants of primate abundance in Maracá Island, Roraima, Brazilian Amazonia
Authors: Pontes Antonio Rossano Mendes
Published: February 2006

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.
Seasonal changes in diet and diet selection of great bustards (Otis t. tarda) in north‐west Spain
Authors: Lane S. J. , Alonso J. C. , Alonso J. A. , Naveso M. A.
Published: February 2006

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.
Ontogenetic changes in mineralization and bone geometry in the femur of muskoxen (Ovibos moschatus)
Authors: Heinrich R. E. , Ruff C. B. , Adamczewski J. Z.
Published: February 2006

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.
Specific distinctness and biogeography of the dwarf chameleons Brookesia minima, B. peyrierasi and B. tuberculata (Reptilia: Chamaeleonidae): evidence from hemipenial and external morphology
Authors: Glaw Frank , Vences Miguel , Ziegler Thomas , Böhme Wolfgang , Köhler Jörn
Published: February 2006

In a recent paper Raxworthy & Nussbaum (1995) included the Madagascan dwarf chameleons Brookesia peyrierasi and 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.
Forage chemistry and fermentation chambers in Svalbard reindeer (Rangifer tarandus platyrhynchus)
Authors: Sørmo W. , Haga Ø. E. , Gaare E. , Langvatn R. , Mathiesen S. D.
Published: February 2006

Seasonal changes in the species composition and fibre content of plant fragments in the rumen and the gross anatomy of the gastrointestinal tract were investigated in Svalbard reindeer Rangifer tarandus platyrhynchus in western parts of Spitsbergen (Nordenskiöld Land (NL), 78°N), where the tundra vegetation is relatively abundant, and on the island of Nordaustlandet ((NA) 81°N) where, in the polar desert, plants are scarce. Reindeer were killed while grazing on NL in autumn (n= 19) and in winter (n= 10) and on NA in summer (n= 10) and in winter (n= 3). Rumen contents included mainly mosses and grasses in specimens from NL and mainly Saxifraga spp. in specimens from NA. The plant cell wall content of the dry organic matter in the rumen‐reticulum (RR) ranged from 55% to 77% and from 43% to 57% in NL and NA specimens, respectively, and did not vary between seasons. In autumn, the wet weight of the contents of the RR ranged from 13% to 20% of body mass (BM) in females on NL and from 14% to 24% of BM in adult reindeer in winter. On NA, the wet weight of the contents of the RR in adult animals ranged from 15% to 20% of BM in summer and from 15% to 17% of BM in winter in NA. The ratio of the wet weight of the contents of the distal fermentation chamber (DFC) to the wet weight of the contents of the RR was 1:8 in females in autumn, compared to 1:6–1:7 in adult animals on NL in winter. The ratio of the wet weight of the DFC to the wet weight of the RR ranged between 1:8–1:10 in summer, compared to 1:7 and 1:8 in winter. There were no significant differences in the size of plant particles in the RR contents in females from the two areas in any season, indicating that ruminal plant particle size was not influenced by the concentration of plant cell walls in the rumen contents. We conclude that the degree of filling of the gastrointestinal tract of these reindeer was therefore principally a function of plant fibre chemistry. Svalbard reindeer are adaptable intermediate feeders but they have, nevertheless, developed a large DFC similar to that of concentrate selectors.
The remarkable anatomy of the giraffe's neck
Authors: Solounias N.
Published: February 2006

Mammalian cervical vertebrae 6 and 7 and thoracic vertebra 1 possess many distinguishing characteristics. In the giraffe, bone morphology, muscle origins and insertions, as well as the location of the brachial plexus (described as many osteological and some soft tissue characters) are identical to those in other mammals but are all displaced posteriorly by one vertebra. There are two exceptions to these observations: the pre‐sacral vertebral count is unchanged when compared with that in the okapi and C7 supports the first rib. Thus, one vertebra has been added in the neck of the giraffe between cervical 2 and 6, and some type of structural blending has occurred in the region of the first rib. The junction of the giraffe neck with the thorax is unusual and results in a protruding forelimb. It is possible that the unusual position of the neck relates to balancing of a cantilevered neck and head upon a relatively slight body. Characteristic drinking postures may have also influenced the observed anatomical modifications.
The effect of lamellae autotomy and sexual size dimorphism on startle‐response performance in larvae of a lestid damselfly (Odonata)
Authors: Stoks R.
Published: February 2006

Swimming is the most important escape mechanism in lestid damselflies. The effect of lamellae autotomy and sexual size dimorphism on startle‐response performance was studied experimentally in larvae of the lestid damselfly Lestes sponsa. In contrast with the prediction of McNeill (1960) that lamellae loss would not affect swimming speed in fast swimmers such as Lestes larvae, swimming performance decreased in a quadratic way with the removal of subsequent lamellae. Lamellae autotomy therefore will considerably reduce the probability of escape from a predator. Larger larvae swim faster than smaller ones of the same instar. This may contribute to a higher survival of larger larvae compared with smaller ones when confronted with both conspecific and heterospecific predators. Despite larvae showing sexual size dimorphism, with females being larger, no difference in swimming speed between the sexes was found.
Reproductive success, colony size and roost temperature in attic‐dwelling bat Myotis myotis
Authors: Zahn Andreas
Published: February 2006

Some cave‐dwelling bat species such as Myotis myotis now also roost in buildings in parts of their range. I studied the effects of roost temperature and colony size on reproductive success of colonies of M. myotis located in buildings. Temperatures in attics fluctuated considerably and altered the thermal conditions at the roost during the breeding season. Inter‐colony variation was recorded with respect to factors indicating reproductive success (number, growth, and mortality of juveniles until fledging). However, over‐winter survival varied more between years than between colonies. Colony size did not influence development or mortality of juveniles. High average roost temperatures favoured development of juveniles but did not influence mortality. Unlike the situation in caves, large colony sizes are not advantageous in buildings
Ecological factors affecting the feeding behaviour of pangolins (Manis temminckii)
Authors: Swart J. M. , Richardson P. R. K. , Ferguson J. W. H.
Published: February 2006

The diet and foraging behaviour of 15 radio‐tagged pangolins were studied in the Sabi Sand Wildtuin for 14 months, together with the community composition and occurrence of epigaeic ants and termites. Fifty‐five ant and termite species of 25 genera were trapped in pitfalls of which Pheidole sp. 2 was the most common (27% occurrence). Five termite and 15 ant species were preyed on by pangolins. Six of these species constituted 97% of the diet while ants formed 96% of the diet. Anoplolepis custodiens constituted the major component of the pangolins' diet (77% occurrence) while forming only 5% of the trapped ants. Above‐ground ant and termite activity was higher during summer than during winter (an 11‐fold difference for A. custodiens), and the above‐ground activity was also higher during the day than at night. Pangolins fed for 16% of their foraging time. However, 99% of the observed feeding bouts (mean duration 40 s) were on subterranean prey. The mean dig depth was 3.8 cm. Prey from deeper digs were fed upon for longer periods. A model taking into account various ant characteristics suggests that ant abundance and ant size are the two most important factors determining the number of feeding bouts that pangolins undertake on a particular ant species. Temperature effects on ant activity and their nest characteristics may exclude pangolins from parts of southern Africa.
The social organization and breeding system of Brants' whistling rat (Parotomys brantsii)
Authors: Jackson T. P.
Published: February 2006

Brants' whistling rat Parotomys brantsii is a gregarious rodent that undergoes marked population fluctuations every few years. Previous studies have variously described them as solitary or social. In this field study, based on direct observations, the social structure and breeding system of a population that almost quadrupled over 7 months was investigated. At the onset of the breeding season, the animals were solitary, each occupying a separate warren. By the end of the breeding season, there was multiple occupancy of some warrens. Each individual maintained a discrete territory within the warren, and exhibited no apparent social behaviour. Outside the breeding season the behaviour of males and females did not differ and both remained at their resident warrens. During the breeding season male P. brantsii visited more neighbouring warrens than did the females, and their visits were to unoccupied warrens or to those occupied by females. Females tended to remain within their own warren. Both sexes avoided warrens occupied by males and few male–male interactions were observed. Females were solicited at their warrens by males, who were frequently chased away. There was, however, evidence that reproductively receptive females were more tolerant of males, who may guard females following mating. This breeding system, based on competitive mate searching by males, and not overt aggression between males, parallels the scramble competition polygyny described for a number of other species, including North American ground squirrels.
The timing of hunting in short‐eared owls (Asio flammeus) in relation to the activity patterns of Orkney voles (Microtus arvalis orcadensis)
Authors: Reynolds Peter , Gorman Martyn L.
Published: February 2006

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.
Diversity and structure of terrestrial small mammal communities in different vegetation types on the Accra Plains of Ghana
Authors: Decher Jan , Bahian Luri Kanton
Published: February 2006

Small mammal communities (shrews and rodents) were studied using mark‐and‐recapture techniques from November 1991 to June 1992 at six sites on the Accra Plains of Ghana. The sites were two traditionally protected ‘sacred groves’, two plots in the legally protected Shai Hills Resource Reserve, and two fire‐protected sites: secondary forest and a Gmelina tree plantation. A total of 241 individuals representing four species of shrews and nine species of rodents was caught. Abundance, diversity, and composition of small mammals varied greatly between sites. Praomys tullbergi was the most abundant species in the sacred groves, whereas Mastomys erythroleucus dominated in the fire‐protected site and in the plantation. The more open grassland areas in the Shai Hills were dominated by Lemniscomys striatus and Uranomys ruddi. Shrews were caught only in forests having dense leaf litter. Legally protected reserve sites had the highest diversity of small mammals but population densities were low. In contrast, the sacred groves had lower diversity levels but much higher population densities, resulting in 1.9 to 14.6 times the biomass of any of the other sites. The rodents Mus minutoides and Hylomyscus alleni and the shrews Crocidura buettikoferi and C. lamottei were found only in the sacred groves. Sacred groves play an important socio‐cultural role. Their local ecological and economic importance as reservoirs for rare and useful plants is well known. This study shows that they are also important refuges for certain small mammal species and support characteristic mammal communities. An attempt to measure the impact of the invading exotic tree Azadirachta indica (neem tree) on small mammals was inconclusive, although trapping success was low in areas with dense stands of neem.
Body measurements on 40 species of mammals from French Guiana
Authors: Richard‐Hansen C. , Vié J.‐C. , Vidal N. , Kéravec J.
Published: February 2006

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.
The effects of predators on fragmented prey populations: a case study for the conservation of endangered prey
Authors: Macdonald David W. , Mace Georgina M. , Barretto Guillermo R.
Published: February 2006

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.
Habitat effects on the spatial ecology of the European badger (Meles meles)
Authors: Feore S. , Montgomery W. I.
Published: February 2006

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.
The diet of otters (Lutra lutraL.) in Danish freshwater habitats: comparisons of prey fish populations
Authors: Taastrøm H.‐M. , Jacobsen L.
Published: February 2006

Otter spraints from five Danish freshwater localities were analysed. In all localities fish was the main prey (76–99% of estimated bulk), especially in winter. Depending on locality, the prey fish mainly consisted of cyprinids (Cyprinidae), percids (Percidae) or salmonids (Salmonidae). Seasonal variations were found in the diet corresponding to the availability of prey. Non‐fish prey categories, such as frogs, birds, mammals and invertebrates, were most frequently taken in spring and summer, but only frogs made an important contribution to the diet (0–21%). The results of analysing 978 otter spraints were compared with prey fish populations as estimated by electrofishing. It was concluded that the fish species composition in the otter diet generally reflected that of the foraging area, however, with the exception of a negative preference for trout (Salmosp.) and a preference for sticklebacks (Gasterosteidae) in some of the study areas. Otters generally took all available sizes of fish with a tendency for selecting individuals between 9–21 cm, though the preferred size of eels was 18–36 cm. A principal component analysis showed that the variation in diet between the localities was associated with differences in fish communities between free‐flowing rivers and lake outflows.
Reproduction and abundance of the fat sand rat (Psammomys obesus) in relation to weather conditions in Tunisia
Authors: Fichet‐Calvet E. , Jomâa I. , Ben Ismail R. , Ashford R. W.
Published: February 2006

The fat sand rat Psammomys obesus is the main reservoir host of cutaneous leishmaniasis in North Africa and western Asia. In order to understand better the transmission of this disease to humans, a longitudinal study of a population of the rodent was carried out in Tunisia. Rodents were collected in 10 trapping sessions between May 1995 and January 1997, using mole traps and cage traps. The structure of the population was established from eye lens weights and the reproductive state was determined on dissection. Reproduction took place continuously from autumn 1995 to spring 1996 with sexual activity rates from 60–65% in females and 23–100% in males. The mean litter size rose from 3.6 in September to 6.1 in March. Reproduction ceased completely in the summer of 1996, and did not start again till January 1997, following an apparent failure in the autumn. Animals born early in the breeding season bred at an early age, but those born later delayed breeding till the following season. At most times the population clearly consisted of two cohorts, one born in the most recent breeding season, and one born in the preceding one. In response to the reproductive cycle, population numbers showed an increase in winter and a decline in summer. The peak observed in March 1996 was due to the sexual activity of multiparous females and young breeding females. At this time there was a female bias in the sex ratio. In a winter dry period, favourable habitat for breeding was confined to an area in which several species of Chenopodiaceae were associated. Sexual activity in females was clearly correlated with rainfall and rain days, with a 1 month delay (r= 0.78; P= 0.007). Male sexual activity was independent of weather conditions. This result is comparable with other rodents of Sahelian or tropical conditions. The increase in fertility was unrelated to age and is discussed in the light of food availability as a proximate factor. The persistence of the parasite causing cutaneous leishmaniasis in host populations is discussed.
Structure of specialized osmetrichia in the brown antechinus Antechinus stuartii (Marsupialia: Dasyuridae)
Authors: Toftegaard C. L. , Bradley A. J.
Published: February 2006

The ultrastructure of specialized sternal gland hairs from the brown antechinus Antechinus stuartii was studied using a scanning electron microscope. The centre of the sternal gland of male A. stuartii possesses short and stiff hairs that are capable of holding a large mass of lipids. The morphology of these hairs differs from those of the dorsal region of the same individual and sexual dimorphism is observed. The osmetrichia of the sternal gland region of male A. stuartii have flared and thickly packed cuticular scales. These scales differ morphologically from the large flattened conical scales of hair from the female sternal region and male dorsum. The surface of the osmetrichia is soaked with the red, oily secretion of the sternal gland, and the angled scales of the cortex have been modified into special ridged chambers which store the glandular secretions. We suggest that in A. stuartii the unique cuticular structural modifications may serve in the retention and delayed oxidation of olfactory cues at the time of breeding.
Acoustic exaggeration of size in birds via tracheal elongation: comparative and theoretical analyses
Authors: Fitch W. T.
Published: February 2006

At least 60 bird species possess an elongated trachea that typically forms loops or coils within the sternum or thorax. This peculiar trait has been known for centuries, and a wide variety of hypotheses have been proposed for its function. However, none of these hypotheses adequately accounts for its existence in all of the diverse bird species and habitats in which it is found. In this paper it is proposed that tracheal elongation serves to exaggerate the apparent size of a vocalizing bird. In normal birds, trachea length is correlated with body size, and thus the acoustic correlates of trachea length in bird calls could convey information about size. By manipulating such an acoustic cue (formant frequency dispersion), tracheal elongation allows a caller to duplicate sounds produced by a larger bird. Unlike previously‐proposed hypotheses, this ‘size exaggeration’ hypothesis is found to be consistent with current theories of avian vocal production and a wide range of comparative ecological and behavioural data. A number of new predictions of the hypothesis are found to be upheld. Finally, tracheal elongation is considered as a possible example of ‘sensory exploitation’, and its ultimate functional significance in mate choice and/or territoriality is discussed.
Gape size and evolution of diet in snakes: feeding ecology of erycine boas
Authors: Rodríguez‐Robles Javier A. , Bell Christopher J. , Greene Harry W.
Published: February 2006

The Macrostomata accounts for more than 85% of extant snakes and is characterized by increased mobility of the jaws and increased gape size. We used stomach contents of museum specimens and specific literature records to describe the food habits of a basal clade of macrostomatan snakes – the erycine boas (Erycinae) – with an emphasis on the North American Charina bottae. Mammals, lizards, birds, and squamate eggs composed 66%, 17%, 7%, and 5%, respectively, of the prey of C. bottae. Smaller C. bottae fed on squamate eggs and lizards, whereas larger snakes added mammals and birds to their diet, and ceased to take squamate eggs. Ten of 12 snakes with multiple prey had eaten nestling birds or mammals, and snakes that ate multiple prey were not significantly larger than those that had single prey. Charina trivirgata and C. reinhardtii also prey on mammals, whereas species of Eryx feed mainly on mammalian prey, but also eat lizards and occasionally birds. Evolutionarily more basal groups of snakes primarily feed on elongate prey, which suggests that innovations of the feeding apparatus of macrostomatans allowed these snakes to eat heavier and bulkier prey, particularly mammals. Erycines appeared and diversified at approximately the same geological time as rodents, suggesting that rodents perhaps constituted an abundant prey resource that favoured the diversification of early macrostomatans.
Acoustic perception of landscape elements by the pond bat (Myotis dasycneme)
Authors: Verboom Ben , Boonman Arjan M. , Limpens Herman J. G. A.
Published: February 2006

We tested the hypothesis that echolocating bats use landscape elements as acoustic landmarks. We predicted that bats should be able to perceive distant landscape elements using echolocation and hence change their echolocation behaviour in relation to these elements. Echolocation parameters of commuting pond bats Myotis dasycneme (Boie, 1825) were related to the bats' distance from banks of different sized canals. Pulse durations emitted while bats flew over canals of 13, 19, and 25 m wide increased successively. Interpulse intervals were equally long at 13, 19, and 25 m wide canals, but significantly longer at a 30 m wide canal. The mean interpulse interval used by bats flying along the midline of the 30 m wide canal was just sufficiently long to prevent overlap of an echo from the canal bank and a new outgoing pulse. The results indicate that pond bats perceive the canal banks by gradually adapting their pulse emissions to the distance to the banks. This suggests a role for the banks as acoustic landmarks.
Discovery of red colobus monkeys (Procolobus badius) in the Niger Delta with the description of a new and geographically isolated subspecies
Authors: Grubb Peter , Powell C. B.
Published: February 2006

A distinctive and geographically isolated population of red colobus monkey Procolobus badius has been discovered in the Niger Delta within what was previously believed to be a discontinuity in the distribution of the species some 1200 km across. This Delta red colobus represents a new subspecies, P. b. epieni, most closely resembling the taxon on Bioko (P. b. pennantii) in such features as black hands and feet, and lack of orange‐brown tones on head and neck, but differing in having whitish arms and hair whorls above the ears. It is less similar to subspecies on the mainland to the west or east (P. b. waldroni in Ghana and P. b. preussi in Cameroon, respectively), implying a complex zoogeographical history for the species. The Delta red colobus occupies an exceptionally low lying habitat of marsh forest, and its range lies within an area that had been independently identified as a centre of primate endemism, so it may have survived climatic vicissitudes of the Pleistocene in a Delta refuge. As it is confined to an area of about 1500 km2, it is now vulnerable to increasing human pressures.
Body size and calling variation in the green toad (Bufo viridis)
Authors: Castellano Sergio , Rosso Alessandra , Doglio Stefano , Giacoma Cristina
Published: February 2006

Green toads from Sardinia are on average 30% longer and twice as heavy as those from the Italian Peninsula. The skeletochronological analysis of an island and a mainland population showed that differences of size were not a consequence of a longer lifespan of island toads, but of their higher growth rate in the pre‐adult stages of life. The effects of these differences of size on the acoustic communication system of the species were analysed. Significant differences were observed in both spectral and temporal properties of the calls. The longer size of insular toads resulted in a reduction of 0.24 kHz of the fundamental frequency. Differences of temporal properties were mostly due to the different thermal conditions of calling males: with respect to mainland toads, island green toads were generally active at lower water temperatures and, at the same water temperature, they had proportionally lower body temperatures.
Dietary constraints upon reproduction in an obligate pollen‐ and nectar‐feeding marsupial, the honey possum (Tarsipes rostratus)
Authors: Wooller R. D. , Richardson K. C. , Bradley G. O.
Published: February 2006

The tiny honey possum, Tarsipes rostratus, is the only marsupial that feeds solely upon nectar and pollen. Its daily energy expenditure is reduced by occasional short‐term deep torpor but its overall nitrogen needs appear to be what would be predicted for its size (7–12 g). Tarsipes derives its nutrients from digesting the contents of pollen grains. Simultaneously, it must eliminate the large volumes of water that accompany the energy‐rich sugars in nectar. We suggest that these two time‐consuming processes, together with the need to harvest small amounts of nectar and pollen from a large number of flowers, limit the rate at which Tarsipes can raise young. Tarsipes has a small litter (2–4 young) compared with marsupials of similar size and its young grow only slowly, both traits that may stem from dietary constraints. However, it breeds first only 4 months after leaving the pouch and continuously thereafter, which may offset an annual adult mortality rate of 86%. Unusually in a small marsupial, the young are carried in a pouch until almost weaned, rather than deposited in a nest. This too may be a correlate of the way it harvests nutritionally rewarding plant products. Nectar and pollen are available all year from the flowers of a suite of banksias and dryandras that are Tarsipes' favoured foodplants. Only the species‐rich Mediterranean‐climate heathlands of south‐western Australia appear able to support a small marsupial with such extremely specialized dietary habits, whose life‐history traits reflect the constraints of this unusual diet.
Lip‐curling in redbelly snakes (Storeria occipitomaculata): functional morphology and ecological significance
Authors: do Amaral José Pedro Sousa
Published: February 2006

Redbelly snakesStoreria occipitomaculatahave a characteristic agonistic display involving conspicuous lip‐curling and head distortion. The lip‐curling and head distortion display is similar to head shape‐changes during feeding.Storeria occipitomaculataproduced mouth secretions while displaying. Micrographs of maxillae and observation of changes in head configuration showed that the lip‐curling behaviour ofS. occipitomaculatais related to the presence of carina‐bearing maxillary teeth, which are protruded from the mouth during the display. I compared the behaviour and morphology of this species to other gastropod‐eating snakes and suggest that these behavioural and morphological characteristics have a two‐fold role: in prey capture they aid the capture, the handling, and perhaps the digestion of prey; in predator deterrence they may act as delivery agents for mouth secretions.
Interannual variation in survival of juvenile Weddell seals (Leptonychotes weddellii) from McMurdo Sound, Antarctica: effects of cohort, sex and age
Authors: Hastings K. K. , Testa J. W. , Rexstad E. A.
Published: February 2006

Survival of juvenile Weddell seals Leptonychotes weddellii in McMurdo Sound, Antarctica was examined using 25 years of tagging and resighting data. Using mark–recapture models, we estimated age‐ and sex‐specific apparent survival (survival confounded with emigration) rates of Weddell seals from birth to 6 years of age for 17 cohorts (1973–89). Survival in the first 2 years of life (0.429 and 0.635 for the first and second years, respectively) was lower than annual survival after 2 years of age (0.806), and was significantly lower for males than for females. First‐year survival of the 1978 and 1983 cohorts was significantly lower than average first‐year survival across cohorts. Reproductive rate of adult females was significantly correlated with first‐year survival in concurrent years, but not when first‐year survival lagged reproductive rate by 1 year nor with annual survival after 1 year of age. This correlation, however, was only significant in male first‐year survival, possibly indicating that survival of males is more dependent on maternal or environmental conditions than survival of females. Average weaning mass varied significantly among cohorts and was nearly correlated to reproductive rate of adult females. This may indicate that maternal condition is reduced in years of low reproduction although more data are needed to test this conclusively.
Reproductive biology of the brush‐tailed phascogale, Phascogale tapoatafa (Marsupialia: Dasyuridae)
Authors: Millis A. L. , Taggart D. A. , Bradley A. J. , Phelan J. , Temple‐Smith P. D.
Published: February 2006

This study investigated the reproductive biology of a captive population of brush‐tailed phascogales Phascogale tapoatafa. A ‘round robin’ mating system was established in which seven adult male animals were rotated through seven adult females. Changes in vaginal cytology and peripheral plasma progesterone and oestradiol levels were monitored to determine features of the female reproductive cycle. Regular measurement of scrotal diameter, collection of testicular biopsies and monitoring of plasma testosterone levels was used to assess male reproductive activity. Oestrous cycle length was estimated as 40 ± 5 days (n= 7) and gestation length as 27 ± 5 days (n= 7). Plasma progesterone levels showed no significant variation. This negative result is attributed to the small sample size (n= 4). Plasma oestradiol levels however, followed the predicted pattern, with an increase in peripheral concentration occurring prior to the breeding season. Oestradiol concentration peaked at 246.9 ± 169.2 pg ml−1 (mean ±se) just before mating and declined to 24.3 ± 12.0 pg ml−1 after mating. Histological studies of testicular biopsies revealed that spermatogenesis does not cease until after the breeding season has begun, in contrast to Antechinus species, in which spermatogenesis ceases before breeding. Plasma testosterone levels increased at the onset of the breeding season, peaking at 6.3 ± 0.60 ng ml−1. Testosterone concentrations remained high until approximately 3 weeks after breeding, followed by a decline to pre‐breeding levels. Litter size and sex ratio did not vary significantly between first‐ and second‐year females. Females did not undergo a second oestrous cycle when pouch young were removed 15 and 17 days after parturition.
Semi‐quantitative assessment of wing feather mite (Acarina) infestations on passerine birds from Portugal. Evaluation of the criteria for accurate quantification of mite burdens
Authors: Behnke J. , McGregor P. , Cameron J. , Hartley I. , Shepherd M. , Gilbert F. , Barnard C. , Hurst J. , Gray S. , Wiles R.
Published: February 2006

Wing feather mite burdens on seven species of passerine birds (Carduelis carduelis– goldfinch;C. chloris– greenfinch;Serinus serinus– serin;Sylvia atricapilla– blackcap;Sylvia melanocephala– Sardinian warbler;Turdus merula– blackbird;Passer domesticus– house sparrow) from Portugal were assessed by the subjective semi‐quantitative scoring system of Behnkeet al. (1995) in order to evaluate more fully the accuracy and reliability of the technique. Our analysis indicated that in all species, scores allocated to flight feathers showed a significant positive relationship with mite counts as assessed through microscopical examination of the same feathers. However, there were differences between species of birds. Of the species examined, goldfinches and greenfinches showed the weakest relationships between assigned mite scores and actual mite numbers indicating that the technique was less accurate when applied to these species compared with the remaining five. No evidence was found that anything more was to be gained from scoring both wings, rather than just one. Feather mites (Proctophyllodesspp.,Trouessartia incisa) were also detected on tail feathers, but the assessment of these feathers presented additional problems and it was concluded that in the interests of minimizing handling time of birds, tail scores had little more to offer. We conclude that scoring all the flight feathers (including all primary, secondary, and tertiary feathers) on one entire wing, but alternating between left and right wings of birds within a species, represents an acceptable compromise between sufficiently detailed examination and minimization of bird handling time in the field.
Food niche overlap and ecological separation amongst six species of coexisting forest shrews (Insectivora: Soricidae) in the Russian Far East
Authors: Churchfield S. , Nesterenko V. A. , Shvarts E. A.
Published: February 2006

The feeding habits and foraging modes of six species of shrew (Insectivora, Soricidae) coexisting in the forests of the Russian Far East were investigated in order to quantify levels of niche overlap and elucidate the role of body size in ecological separation. Overlap in numbers of shared prey taxa was high and Lithobiomorpha, one of the most abundant macro‐invertebrates in field samples, was a major prey item of all species. The composition of different prey taxa in the diet ofSorex unguiculatusand the abundance of these taxa in field samples were positively correlated. Major differences in dietary composition and foraging mode reflected body size of shrews. While the niches of individual species were not exclusive, small species fed only on arthropods, were epigeal, and had relatively narrow niche breadths. Large species fed extensively on lumbricids and other soil‐dwelling invertebrates, and were hypogeal. There were significant negative correlations between niche overlap in terms of prey composition, prey size and prey location, and increasing body‐length ratios in pair‐wise comparisons. Combined niche overlap was reduced with increasing divergence of body size. Adjacent species‐pairs in the size series had a mean combined niche overlap of 88% compared with non‐adjacent pairs of 67%. The most significant areas of ecological separation between species as a function of body size were in the dietary occurrence of small versus large prey and in the foraging mode (epigeal versus hypogeal). These findings confirm that body size has an important role in effecting ecological separation in multi‐species communities where a high degree of morphological and ecological similarity occurs between members.
A new species of vespertilionid bat from Taiwan and a revision of the taxonomic status of Arielulus and Thainycteris (Chiroptera: Vespertilionidae)
Authors: Csorba Gábor , Lee Ling‐Ling
Published: February 2006

On morphological and chromosomal grounds Pipistrellus (Arielulus) subgenus is elevated to generic rank and the recently described genus Thainycteris has been synonymized with Arielulus. Besides this taxonomic revision, a new species of bat Arielulus torquatus is described from the central mountains of Taiwan which differs from its congeners chiefly by its size and colouration.
Selection of nest trees by southern flying squirrels (Sciuridae: Glaucomys volans) in Arkansas
Authors: Taulman James F.
Published: February 2006

Natural nest‐site selection was investigated in 50 radiocollared southern flying squirrels Glaucomys volans during spring and summer, 1994–1996, in the Ouachita National Forest of Arkansas. Squirrels nested in 226 trees in a variety of habitats at five study areas. Contrary to previous reports describing southern flying squirrels as habitat generalists, in this study squirrels showed selection in both the habitat and tree type in which nests were placed. Where it was available, mature pine–hardwood forest was selected for nesting. Young (< 15 years old) and immature (15–40 years old) pine plantations and harvested areas were avoided as nesting habitats. At harvested study areas, squirrels nested in protected riparian mature forest strips (greenbelt) along, and 10–20 m either side of, intermittent creeks and in adjacent mature forests. Squirrels constructed only outside nests in pine trees. In mature pine–hardwood forest, pines were used for outside nests more frequently than hardwoods; in greenbelt habitat, pines and hardwoods were chosen equally for outside nests. Both outside and cavity nests were found in hardwoods; standing dead trees (snags) contained only cavity nests. Snags were selected over hardwoods for cavity nesting in both mature pine–hardwood forest and greenbelt habitat. All hardwood species and all decay classes of snags were used for diurnal nesting in greater frequency than expected. Considering both cavity and outside nest‐site selection, pines were used less than expected. Results suggest that mature forests are optimal flying squirrel nesting habitats and should be retained adjacent to harvested areas to provide resources to squirrels abandoning stands after disturbance. Within harvested areas, nesting habitat can be substantially improved through the retention of overstory hardwoods and snags, as well as protection of mature forest strips along drainages.