bluuebunny/crossref_metadata_2025_split huggingface dataset:
Habitat effects on the spatial ecology of the European badger (Meles meles)
Authors: Feore S. , Montgomery W. I. 
Published: February 2006

AbstractThis 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

AbstractOtter 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

AbstractThe 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

AbstractThe 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

AbstractAt 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

AbstractThe 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

AbstractWe 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

AbstractA 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

AbstractGreen 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

AbstractThe 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

AbstractRedbelly 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

AbstractSurvival 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

AbstractThis 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

AbstractWing 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

AbstractThe 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

AbstractOn 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.