bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal Patterns of Basking Behaviour in a Mediterranean Lacertid Lizard
Authors: Diaz JOSÉ A.
Published: April 2008

1. I studied the thermoregulatory behaviour of the diurnal basker Psammodromus algirus (Reptilia, Lacertidae) in the mosaic of sunshade patches of a Mediterranean evergreen forest. 48 behavioural sequences associated with measurements of the thermal environment provided data on the percentages of time spent basking by focal animals, the duration of individual basking periods and the frequency of basking. 2. The percentage of time basking decreased linearly from the onset of the activity period until midday. The average duration of basking periods had a pronounced decrease after 0700 h and remained constant throughout the rest of the morning, whereas the basking rates, that were minimal before 0700 h, reached a peak between 0700 and 0800 h followed by a progressive fall that continued until noon. 3. In order to explain these behavioural patterns, I experimentally determined the effects of environmental variables (air and ground temperature and solar angle) on the heating and cooling rates of captive lizards. The resulting regression models were then used to predict the heat exchange rates of the observed free-ranging animals. 4. The moment at which heating rates should equal and then exceed cooling rates, appeared to set off the behavioural shift towards a larger frequency of shorter basking periods. Under these circumstances, the apparently random movement of a shuttling heliotherm with respect to sun and shade might still be of thermoregulatory significance.
Passing as an Indicator of Social Dominance Among Female Wild and Domestic Norway Rats
Authors: Ziporyn Terra , McClintock Martha K.
Published: April 2008

The most frequent form of social interaction between pairs of wild or domestic rats (Rattus norvegicus) was passing behaviour in the narrow burrows and open field of seminatural environments. This behaviour occurs when a moving rat approaches another, either head-to-head or head-to-tail; the passed animal freezes while the passing rat continues, side touching side. The social dominance manifest by this behaviour correlated significantly with fighting dominance, particularly among female wild and domestic rats. In addition, dominance during displacements for access to food and water correlated with the dominance relationship in passing within pairs of domestic female rats. Although both passing and general activity had the same crepuscular daily rhythm, passing dominance did not correlate with individual differences in general activity level. Thus passing indicates social order and is not simply a by-product of general activity. Because passing occurs ten times more frequently than fights, in future studies it may be a more powerful indicator of female dominance and social order.
Socialisation Tactics of the Spectacled Parrotlet (Forpus Conspicillatus)
Authors: Garnetzke-Stollmann Kyra , Franck Dierk
Published: April 2008

Spectacled parrotlets live in a complex system of individual relationships throughout their lives. The adults form exclusive pair bonds, addressing all friendly and sexual behaviour patterns to each other. Pair mates cooperate in agonistic situations. As long as they stay close together they hold the same rank-order position. In mate-choice experiments females (not males) significantly preferred a mate which formerly held a high social position. There are also non-exclusive pair bonds, which are far less stable than exclusive ones. Only exclusive pairs have a good chance to occupy a breeding cavity. All group members are synchronized in many of their activities, such as foraging, preening or resting. They are keenly interested in unusual activities of other group members. Social learning, including copying sexual techniques, seems to be essential. After fledging the parents keep their offspring at a distance from a very early stage. Instead of a close parent-offspring relationship the fledglings form sibling groups with their nest mates. Over a period of months siblings remain the main interaction partners for all friendly and playful activities. They also support one another in agonistic situations. In the first months of life even courtship feeding and sexual behaviour are addressed predominantly to siblings. Thus a pair-like relationship is established between siblings, anticipating the permanent pair bond of adults. Single fledglings, deprived of the experience of a sibling group, remained poorly integrated into the group. They developed alternative socialisation tactics, namely (1) joining a host group of unrelated siblings, (2) renewing a friendly partnership with the parents, (3) helping to protect and feed younger siblings or even unrelated fledglings and (4) seeking early partnership with unrelated group members. Out of 10 single fledglings only the one that was accepted by a host sibling group immediately after fledging became well integrated into the whole group and reproduced well. It is argued that sibling groups offer good opportunities for learning partnership and function as a safe basis for exploring the social environment. It is tentatively proposed that single fledglings have a decreased probability of reproductive success.
Insemination Temporarily Inhibits Sexual Responsiveness in Female Salamanders (Desmognathus Ochrophaeus)
Authors: Verrell Paul A.
Published: April 2008

After successful courtship and mating in the mountain dusky salamander (Desmognathus ochrophaeus), sperm masses remained externally visible in the cloacae of females for as long as 24 h (Experiment 1). When mated females were exposed to males for a second time, they appeared to be attractive and were subjected to courtship, but they seldom became inseminated (Experiment 2). Courtship and mating appear to result in a temporary inhibition of female sexual responsiveness. Females whose sperm masses were removed on the morning following successful insemination were more likely to become inseminated during a second encounter than were females whose masses were left in situ (Experiment 3). This suggests that it is the presence of a sperm mass, not simply exposure to stimulation produced by males during courtship, that inhibits female sexual responsiveness. In Experiment 4, a small styrofoam ball was placed into the cloacae of females with no recent courtship experience. When paired with males, females bearing "surrogate" sperm masses exhibited lowered courtship frequencies similar to those of recently-mated females, suggesting that physical stimulation of the female cloaca is sufficient to inhibit female sexual responsiveness. Subtle manipulation of female sexual responsiveness by males probably does not occur in Desmognathus ochrophaeus.
Variation in Parental Care of Common Goldeneye (Bucephala Clangula) Females
Authors: PÖYSÄ Hannu
Published: April 2008

Factors affecting the variation of parental care were examined in the precocial, nidifugous common goldeneye (Bucephala clangula), a species with uniparental female care. Parental care, measured as the time spent by the female in rearing the brood, varied considerably. Habitat shelterness and food abundance in brood rearing lakes did not affect the duration of parental care. Brood mortality and size affected females' decision to abandon the brood; broods left younger experienced higher mortality during the parental care and were smaller than broods reared for longer. Offspring left by a female did not have higher mortality than same-aged offspring not left. Broods that were deserted early did also produce young to the fledging age.
Sex Differences in Patterns of Association Among Indian Ocean Bottlenose Dolphins
Authors: Smolker Rachel A. , Richards Andrew F. , Connor Richard C. , Pepper John W.
Published: April 2008

Patterns of association among bottlenose dolphins resident in Shark Bay, Western Australia were analyzed using party membership data. Parties contained an average of 4.8 individuals, but party size and composition were unstable. While these temporary parties often contained both males and females, long term consistent associations generally were between members of the same sex. The highest association coefficients, resulting from very frequent co-occurrence within parties were between males and between mothers and offspring. Males formed subgroups of two or three individuals who consistently associated with each other, and these were stable over periods of at least seven years in some cases. Male subgroups preferentially associated with particular other male subgroups. Females associated most consistently with other females, although not to the same extent as some males. Female associations were better described as a network rather than discrete subgroups. Male-female associations were generally inconsistent and depended in part on female reproductive state. Mothers and their offspring associated very consistently for at least 4 years.
Observations On Nursing Behaviour of Hooded Seals, Cystophora Cristata
Authors: Perry Elizabeth A. , Stenson Garry B.
Published: April 2008

This study reports the first quantitative data on nursing behaviour of hooded seals which have a four-day nursing period, the shortest known for any mammal. Twenty mother pup-pairs were observed at a whelping patch off the coast of Newfoundland, Canada during March, 1990. A total of 38 nursing sessions were recorded in 19 hours of observations. Pups nursed for an average duration of 5.5 min and at a frequency of approximately 2.4 bouts/ hour. Morning and afternoon rates were similar (x = 2.5 bouts/hr and x = 2.4 bouts/hr, respectively) and nocturnal nursing was witnessed. Pups were nursing for 18% of the total observation time which, assuming no diurnal pattern, would total 4.3 hr per day, the highest daily nursing duration reported for any phocid. We concluded that hooded seal nursing behaviour is another important factor in the unique lactation strategy attributed to a particularly unstable environment. It helps to ensure that pups attain sufficient weaning mass, double their birth weights, in the four-day nursing period.
Population and Sex Differences in Colour Vision in the European Minnow Phoxinus Phoxinus (Cyprinidae)
Authors: Hofstetter Catrin , Ward Paul I.
Published: April 2008

The abilities of males and females from two populations of the European minnow Phoxinus phoxinus to discriminate between disks of different colours were compared. Fish were trained to feed at a disk lit with 'orange-yellow' light. Their ability to discriminate this training colour from others was then tested. Fish from a stream population were more accurate than those from a lake population and females more accurate than males. We cannot be completely sure the fish discriminated on colour rather than perceived brightness, though we tried to control for the latter. There were no significant differences in the times taken to perform the tests. We suggest the different visual environments in the two habitats have selected for different visual abilities. As males and females spend most of the year in shoals together, it is argued that the difference between males and females has evolved because of the females' need to discriminate between males' sexual displays during the breeding season. The results show that a fish's sex and perhaps its population of origin should be considered in tests of visual ability.
Density Dependent Song Duration in the Grasshopper Omocestus Viridulus
Authors: Eiriksson Thorleifur
Published: April 2008

Although duration of grashopper song is species specific, there is also considerable variation within species. One possible reason for this is that males are adjusting their singing tactics in relation to the density of competitors. Males are expected to sing shorter songs when other males are nearby to enhance the probability of hearing female response or to listen to other males. To test this hypothesis an experiment was performed by placing different numbers of Omocestus viridulus males in large outdoor cages and monitoring their singing behaviour. The results show that males sing on average shorter calling songs as the number of males increases. It was also found that males compensate for singing shorter songs by singing more songs, so the total time spent singing stays similar at all densities. The scenario is complicated by the singing of very short songs which are mainly, but not exclusively, used in male-male interactions. The probability that males sing rivalry songs increases with the density of males and the number of these songs increases as male-male interactions get longer. The results suggests that part of the variation in the duration of calling songs reported in several field studies is caused by a change in singing tactics at different densities of males. The function of rivalry songs is not clear. These songs may function in the spacing of males or may be an extremely short form of the normal calling song used when other males are very close.
Courtship Behavior of the Small-Mouthed Salamander (Ambystoma Texanum): the Effects of Conspecific Males On Male Mating Tactics
Authors: McWilliams Scott R.
Published: April 2008

1. The courtship behavior of A. texanum consisted of a rapid nudging period followed by males producing many spermatophores, some of which were picked up by the female. Neither amplexus or leading by the male were integral components of courtship. Consequently, proposed geographic variation in A. texanum courtship remains unsubstantiated. 2. Courtship behavior of A. texanum and A. barbouri (formerly pond and stream form A. texanum, respectively) is very similar; only the location of courtship and perhaps the frequency of sexual interference tactics are different for these two sibling species. 3. A. texanum courtship is rapid, males produce large numbers of spermatophores per courtship and invest little courtship time per spermatophore, and intermale competition is extreme. 4. Male A. texanum promote their sexual success using sexual interference behavior (e.g. covering other spermatophores with their own) and to a lesser degree sexual defense behavior (e.g. forcefully nudging rival males). 5. Male sexual success is primarily enhanced directly - A. texanum males increase the number of spermatophores produced when at least two other males are courting the same female. The temporal allocation of these additional spermatophores is adaptive only if males are maximizing the number of ejaculates per female or breeding typically occurs in polygamous aggregations.
Song Function in Gibbons
Authors: Cowlishaw Guy
Published: April 2008

This paper examines variation in the singing behaviour of male and female gibbons in an attempt to construct a consistent framework to describe the function of both solo and duet song bouts. Functional hypotheses are described and tested with the available data. The song bouts of mated females are shown to be strongly associated with the pressure of territorial defence. Conversely, the solo song bouts of mated males show no relationship with territorial behaviour, but are associated with the (estimated) density of floating unmated males in the population. In accordance with the hypotheses under test, these results indicate that mated females sing to defend their territories, whilst mated males sing to repel males in defence of their mate and offspring. Contrary to previous hypotheses, the production of coordinated duets by male and female pairs is found to be unrelated to pairbonding. However, duetting is shown to be associated with encounters and aggression at the territorial boundary, in support of the claim that duetting advertises pairbond presence in order to intimidate neighbours and reduce the costs of territorial conflicts. The implications of these analyses for territorial and mating strategies in gibbons are discussed.
On the Ontogeny of Seed Harvesting Techniques in Free Ranging Ground Squirrels
Authors: Heschl Adolf
Published: April 2008

Occasionally, adult European ground squirrels can be observed to practise a quite complex behavioural technique to obtain seed grains from the top of tall grass plants (e.g. Festuca ovina: 10-70 cm, Poaceae). They bite through the stem of a plant at the basis and, subsequently, know how to handle the fallen stem so as to successfully reach the food. The present field study aimed to analyse the detailed ontogeny which, in growing ground squirrels, leads to this behaviour. Data for 5 juveniles belonging to one litter were collected during an observation period of 38 successive days after the animals' first appearance above ground (video recordings). They show that this behaviour emerges as the final result of a whole series of successive developmental steps involving increasingly more efficient techniques in which simple techniques are gradually elaborated to more sophisticated ones. The underling causal mechanism is supposed to be operant conditioning based on increasingly more complex motor activities involving the animal's paws. Despite frequent social contacts, learning through imitation or even through instruction by the mother turned out to be not an important factor. With regard to cognitive abilities, the observations suggest experiments to verify the hypothesis of a beginning object permanence in ground squirrels.
Song Sharing and Local Dialects in a Population of the European Wren Troglodytes Troglodytes
Authors: Catchpole Clive K. , Rowell Armanda
Published: April 2008

Songs were recorded from a local population of 13 male wrens at Wraysbury Lakes, Berkshire, U.K. during 1991. Sonagraphic analysis revealed that there were 15 distinct song types in the population, and that each male had between three and six song types in his repertoire. Song sharing between neighbouring males was particularly high. Six of the males in the population were on the east bank of the lake, separated from the other seven on the west bank by 200 metres of open water. Although three song types were distributed over the whole area, six were unique to the east bank and six to the west. Any male could be classified as an east or west bank male, by the possession of several distinct song types unique to each 'dialect' area. So far, clear examples of dialects have been largely restricted to species with only one or two song types in their repertoires. Song sharing and the development of local dialects in the wren are discussed in relation to current views on mechanisms of social learning in songbirds.
The Relationship Between Individual Differences in Male Song Frequency and Parental Care in Blackcaps
Authors: Hoi-Leitner Maria , Nechtelberger Heidrun , Dittami John
Published: April 2008

Song rates in male blackcaps were examined over the course of the breeding season and compared with various aspects of mating and later parental behavior in individual birds. Song rates decreased steadily over the breeding season although relative individual rates remained constant. Early territory holders sang more and mated faster than late-comers. Song frequency was positively related to alarm call frequency during nesting but negatively related to male incubation and offspring feeding rates. Surprisingly, under the conditions studied, higher song rates were indicative of higher nesting success. This demonstrates the potential role of song frequency in the advertisement of territorial quality. There may well be either environmentally dependent differences in parental care as adaptations to temperature, food or predation pressure or simply a trade-off for males between singing and parental care, where early arriving males derive greater fitness benefits from singing, while late arriving males benefit more from engaging in parental care.
Antipredatory Behaviour of Feverish Tadpoles: Implications for Pathogen Transmission
Authors: Lefcort Hugh , Eiger Steven M.
Published: April 2008

In this paper we propose the hypothesis that pathogen-induced host defense responses result in altered host behaviors and enhanced predation. In particular we examine the effects of the acute phase response (whose effects include fever, reduced activity and malaise) on antipredatory behavior in bullfrog (Rana catesbeiana) tadpoles. This host response is associated with the preliminary stages of infection with many pathogens yet its behavioral effects have received little attention. Bullfrog tadpoles were injected with alcohol-killed bacteria to induce a response to infection and their ability to detect and avoid capture by predatory salamanders (Taricha granulosa) was explored. We predicted that acute phase responses increase tadpole vulnerability to predation by influencing thermoregulatory behavior and their ability to detect, and avoid capture by, salamanders. We found that the sterotypical effects of the acute phase response can lead to increased predation. Malaise affected the refuge seeking behavior of the tadpoles in the presence of salamanders. We suggest that for tadpoles provided with refuges, altered behaviors are a liability. This endogenous response may afford some parasites a potential pathway to their next host.
Reproductive Competition and Selection On Male Traits At Varying Sex Ratios in the Field Cricket, Gryllus Pennsylvanicus
Authors: Souroukis Konstantine , Cade William H.
Published: April 2008

Intensity of male-male competition and sexual selection were studied in the field cricket, Gryllus pennsylvanicus, in an outdoor arena at four sex ratios, male-only (5:0), male-biased (5:2), unity (5:5) and female-biased (5:10). Fighting frequency was highest at male-biased and unity sex ratios. Fighting success was correlated with male body weight at all sex ratios. Calling duration and searching distance decreased with increased female numbers. Opportunity for selection was highest at the male-biased and lowest at the female-biased sex ratio. Selection gradients and differentials were calculated and demonstrated that direct and total selection was highly variable and often relaxed. Direct selection favored male weight at the male-biased sex ratio and total selection for weight occurred at unity. There was no selection on male weight at the female-biased sex ratio. Total and direct selection for increased calling duration occurred at the male-biased sex ratio. Only total selection for calling duration was found at unity, whereas direct selection acted against calling duration at the female-biased sex ratio. Selection did not act on searching at any sex ratio. Natural variations in sex ratios occur and fluctuations in selection on correlated male traits may maintain additive genetic variation for traits important in male-male competition.
Reconciliation, Consolation, and Redirection in Japanese Macaques (Macaca Fuscata)
Authors: Aureli Filippo , Veenema Hans C. , Van Panthaleon Van Eck Carel J. , Van Hooff Jan A.R.A.M.
Published: April 2008

We studied the occurrence of social interactions after agonistic conflicts in captiveJapanese macaques. We collected data on one group during the mating and the non-mating season and on another group during the mating season only. We compared the social interactions of the victim soon after a conflict with the social interactions of the same individual during control periods, using two different methods. The results obtained with the two methods were very consistent. We found clear evidence for the occurrence of reconciliation and redirection. However, there was no evidence for consolation even when we considered only affiliation between the victim and its own kin or between the victim and the aggressor's kin. Separate analyses for the two groups and the two seasons yielded very similar results.
Functions of Wild Gorilla 'Close' Calls. I. Repertoire, Context, and Interspecific Comparison
Authors: Harcourt A.H. , Stewart K.J. , Hauser M.
Published: April 2008

Individuals in social groups of a number of species produce and exchange among themselves frequent, quiet vocalisations. The function of most such vocalisations, here termed 'close' calls, remains obscure, because of the lack of any obvious context of behaviour associated with their production. In this first of two papers that attempt to determine the function of these calls in wild girilla groups, we describe the call repertoire, the age-sex distribution of frequencies of call-types, the contexts in which the calls are given, compare the above measures with available descriptions for the other African great apes, the common and bonobo chimpanzees, and briefly speculate on possible functions. We provide sonograms and 21 acoustical measures of 15 calls in total, including eight 'close' calls, recorded from identified individuals of two habituated heterosexual groups of wild gorillas (Gorilla gorilla) of average composition for the region. In so doing, we provide the most detailed description yet of any great ape's within-group vocalisations. The age-sex classes differed in their use of 'close' calls: adult males called the most in total, immatures the least; and while most classes gave all calls, they gave them at differing frequencies. The differences were consistent across the two-year study period. We suggest two main contexts of production, namely situations of potential separation, and potentially agonistic situations. Thus animals called when far from others and before changes in group activity, and they called when unusually close to one another, especially while feeding. In comparison to the closely related common and bonobo chimpanzees, gorillas apparently had no calls specific to subordinate individuals behaving submissively: subordinate gorillas gave calls in such a situation, but they and dominants gave the same calls (at our current level of analysis) in other situations also. Acoustically and functionally, the gorilla's 'close' calls can be separated into 'syllabled' grunts and non-syllabled' longer calls, we suggest. 'Syllabled' calls might function to maintain contact between animals, to coordinate activity, and to act as mild threats; 'non-syllabled' calls might function as appeasement signals, and to cohere and coordinate group movement when given at good feeding sites, both by attracting animals to the site, and by inhibiting competition at it.
Mother-Infant Relationships in Three Species of Macaques (Macaca Mulatta, M. Nemestrina, M. Arctoides). I. Development of the Mother-Infant Relationship in the First Three Months
Authors: Maestripieri Dario
Published: April 2008

This study compared mother-infant relationships in rhesus, pigtail, and stumptail macaques living in large captive social groups. Mother-infant pairs were focally observed in 4 weekly 30-min sessions for the first 12 weeks of infant life. Rhesus and stumptail infants were active earlier than pigtail infants, and rhesus mothers further encouraged infant independence by frequently breaking contact with them and rejecting them. Rhesus mothers also restrained their infants, presumably in circumstances where a danger for them was perceived. Pigtail mothers were more protective than rhesus mothers and not as encouraging of infant independence as rhesus mothers. Stumptail mothers scored low on both protectiveness and rejection measures. The functional significance of some differences in mother-infant relationships is tentatively explained on the basis of reproductive, ecological, and social characteristics of rhesus, pigtail, and stumptail macaques. Data on scratching behavior support the hypothesis that behavioral differences among macaque species are associated, at the proximate level, with differences in temperament or emotional reactivity.
Vigilance in Nxai Pan Springbok, Antidorcas Marsupialis
Authors: Bednekoff Peter A. , Ritter Ron
Published: April 2008

Vigilance rates were surveyed on juvenile and adult female springbok in 3 positions (close edge, center, and far edge) in herds of 17 to 536 springbok in Nxai Pan N.P., Botswana. Rates were generally low. They decreased as group size increased but were not lower when other grazers joined springbok herds. Edge animals spent roughly twice as much time vigilant as central animals. Juveniles were slightly less vigilant than adults but this may reflect greater movement. Surprisingly, springbok were more vigilant in late mornings than in early mornings or afternoons. Springbok approaching tree clumps were more vigilant than matched individuals moving in the open. Preliminary data indicate that vigilance is higher at night than during the day and that territorial males have moderate to low levels of vigilance. In general, vigilance varied in ways expected to lower the risk of being taken by ambush predators such as leopards.
Effects of Testosterone On Nest-Box Occupation and Associated Behaviours By Male European Starlings (Sturnus Vulgaris)
Authors: Gwinner Helga , Gwinner Eberhard
Published: April 2008

In an aviary experiment carried out at the beginning of the breeding season in March and April, nest-box occupation and associated behaviours were observed in a group of 18 adult and 18 first-year male European starlings. Nine birds of each group carried a testosterone implant (T-males) and the other 9 an empty implant (C-males). When analyzed for effects of age, first year birds were significantly more active with regard to nest-box inspection and nest-building than adults. When analyzed for effects of treatment, T-males occupied more nest-boxes and visited their nest-boxes more often than C-males. Other activities like singing, nest-box inspection, nest-building and aggressive behaviour were not significantly different between T-males and C-males. We suggest that the absence of a significant effect of T on aggression may be related to the colonial nesting habits of the starling. Since T-males tended to be more active with regard to all behaviours studied testosterone may have led to a general increase in frequency and persistence of behaviour which in turn facilitated nest-box occupation.
Vigilance in African Mammals: Differences Among Mothers, Other Females, and Males
Authors: Burger Joanna , Gochfeld Michael
Published: April 2008

The time devoted to eating, vigilance (or scanning), walking and aggression was studied in one-minute focal animal samples as a function of sex, age, and motherhood for several African animals including African elephant, Burchell's zebra, Cape buffalo, Defassa waterbuck, impala, and Uganda kob. Between 24 and 45 percent of the variation in vigilance behavior was accounted for by location (center or edge of herd), sex, age and whether a female had young. Time of day entered the linear multiple regression models for two species, and surprisingly group size did not enter any of the linear multiple regression models in 1993. In general, females with young were more vigilant than their young or females without young. There were few gender differences in vigilance among animals without young, except that male zebra, wildebeest and waterbuck were more vigilant than females. Animals on the edge of herds devoted more time to vigilance than intermediate or central animals (regardless of sex or age class). Although there was no relationship between group size and vigilance in 1993 when all herds were considered, there was a decrease in vigilance with increasing herd size for impala and kob for herds less than 50. Moveover, herd size and vigilance were negatively correlated in our 1984-1985 study, due partly to differences in group sizes. In 1984-1985 animals were not migrating, and were in relatively small, discrete groups, whereas in 1993 some species were migrating in large herds that stretched for several km. We suggest that in 1993 herd size was above a threshold where increases in group size can lead to further decreases in vigilance. Under these circumstances, location in the herd becomes paramount: Outside animals can be directly exposed to attack. Consequently animals on the edge devote more time to vigilance than central animals.
Comparative Analysis of Time Spent Grooming By Birds in Relation To Parasite Load
Authors: Cotgreave Peter , Clayton Dale H.
Published: April 2008

Although grooming and other kinds of maintenance activity are important components of the behavioural repertoire of terrestrial vertebrates, comparative studies of the proportion of time budgets devoted to maintenance are lacking. Data were collated on the proportion of their time-budgets devoted to maintenance behaviour by 62 different bird species. On average, birds spend 9.2% of the day in maintenance activities, with the major component (92.6%) being grooming. Male birds devoted more time to maintenance than females, except in the case of ducks. Maintenance time does not appear to correlate with morphology, moult, latitude, coloniality or season. However, bird species known to harbour more parasitic louse species spend more time on maintenance than do host species with few lice.
Effects of the Aromatase Inhibitor R76713 On Sexual Differentiation of Brain and Behavior in Zebra Finches
Authors: Balthazart Jacques , Absil Phillipe , Fiasse Veronique , Ball Gregory F.
Published: April 2008

Neonatal estradiol injections masculinize both the singing behavior and some morphological aspects of the song control nuclei in female zebra finches (Taeniopygia guttata), but there is to date no physiological evidence that estrogens are responsible for the differentiation of song and the song control nuclei in male zebra finches during normal ontogeny. Injections of estrogen into young males demasculinizes their copulatory behavior, so that it is difficult to understand how the same endocrine environment could simultaneously masculinize song and demasculinize copulation. Attempts to block early estrogen action in males have resulted in a paradoxical hypermasculinization of several aspects of the song control nuclei. In the present experiment, we tried to evaluate the role played by estrogens during zebra finch differentiation by blocking their secretion with the non-steroidal aromatase inhibitor, R76713 or racemic vorozole. Zebra finches received at 2-3 days post-hatch one Silastic implant filled with R76713 or left empty as a control. Implants were left in place until about 45 days of age and birds were then gonadectomized. At the age of 105 days, all birds received a Silastic implant filled with T and, starting two weeks later, they were repeatedly tested for singing and copulatory behavior during a period of 3 weeks. They were then perfused and their brains were analyzed by histological methods to measure the volume of the song control nuclei, HVc, RA, area X and MAN. Treatment with R76713 significantly decreased (± 50%) the number of song bouts produced by the birds but did not affect the copulatory behavior of the males. The behavior of females was not changed by the aromatase inhibitor and, in particular, no increase in mounting behavior was seen in the treated females. The presence of a strong sex dimorphism in the size of all 4 song control nuclei was confirmed but no significant effect of R76713 on these measures could be detected. These data are therefore consistent with the idea that estrogens are implicated in the differentiation of singing behavior in the zebra finch but the small amplitude of the behavioral effect observed and the absence of morphological effect suggest that either other factors also play a major role at this level or that higher doses or longer treatments with the aromatase blocker should be tested.
Courtship Food-Calling in Burmese Red Junglefowl: I. the Causation of Female Approach
Authors: VAN KAMPEN Hendrik S.
Published: April 2008

The present study was performed to examine why female Burmese red junglefowl (Gallus gallus spadiceus) approach a food-calling male. Females from three small groups were tested individually with a male under different conditions. Deprivation of food for 24 h did not affect the reaction of females to food-calling, showing that the feeding system is not crucially involved. This result makes it unlikely that courtship food-calling with inedible objects is a case of deception, as was suggested previously. Further it was shown that females willing to perform the sexual crouch and females low in the peck-order were more likely to approach food-calling. These factors were found to be interrelated and fear was suggested to play a crucial role both in inhibiting and modulating approach and in willingness to crouch. The data gathered on the involvement of the sexual system did not allow for any definite conclusions, but as an alternative it was suggested that females might approach courtship food-calling because it arouses curiosity, or, exploration.
A New Experiment To Verify the Spatial Range of Pigeons' Olfactory Map
Authors: Benvenuti S. , IOALÈ P. , Nacci L.
Published: April 2008

A series of tests with homing pigeons was carried out to verify the spatial range of their olfactory map. In each test, a group of experimental birds, which had been prevented from smelling ambient odours during the passive displacement, was compared to a group of controls which always had free access to olfactory information. Our results show that the range of unfamiliar area where pigeons are able to navigate on the basis of local cues is rather limited (less than 120 km from the home loft). Homeward orientation, however, normally occurs beyond the limits of the olfactory map as the birds are able to use odorous cues perceived during the initial part of the outward journey. Our results are in agreement with the "mosaic" hypothesis of pigeons' olfactory navigation.
Vulnerability To Predation in Baboon Populations
Authors: Cowlishaw Guy
Published: April 2008

This study investigates patterns of predation in Papio baboon populations across Africa. Using anecdotal reports collated from the primate and predator literature, the following analyses are conducted. First, the primary predators of baboons are identified. These are shown to be the terrestrial carnivores; in order of importance leopards, lions and hyena. Second, patterns of large felid predation on baboons are investigated in detail. In terms of prey selection, leopards are more likely to take (1) adults than juveniles and (2) males than females. While lion attacks are strictly diurnal, leopards will attack during both the day and night. However, both predators are usually limited to conducting attacks when and/or where visibility is limited. Leopards were about twice as successful as lions at hunting baboons. Nocturnal leopard hunts were more successful than diurnal hunts when twilight cases were excluded; in relation to this, leopard attacks at sleeping sites were more likely to end in prey capture than attacks at waterholes. Finally, patterns of baboon retaliation against predators revealed that males are more likely to retaliate than females and that such behaviour effectively deters predators. Males are particularly aggressive towards leopards, where in 4/11 cases the leopard was killed. These results may help to resolve a number of outstanding controversies regarding the nature of predation risk in baboons, indicating that diurnal predation is a substantial threat, that males are effective at deterring several predator species, particularly leopards, and that predators will successfully attack and capture males.
Self-Structuring in Artificial "Chimps" Offers New Hypotheses for Male Grouping in Chimpanzees
Authors: Te Boekhorst Irenaeus J.A. , Hogeweg Paulien
Published: April 2008

Chimpanzees live in societies that are characterised both by disorder and order. On the one hand, party size fluctuates in a randomlike fashion and party membership is unpredictable ; on the other hand, fundamental party structures are apparent; males are often in all-male parties whereas females remain mostly solitary. The customary sociobiological explanation is based on the assumptions that 1) competition for food favors solitariness (especially in females); 2) chimpanzee males share the costs of territorial defense against rivals from neighbouring communities and 3) genetical relatedness among males within a community compensates for fitness losses due to their competition for food and females. We point to some theoretical flaws in the reasoning that forms the basis of the current neo-Darwinistic model and to the lack of empirical data concerning male relatedness. Most importantly, chimpanzee-like party structures emerge by self-organisation in an artificial "world" in which "CHIMPs" do nothing more than searching for food and mates, without requiring any of the assumptions of the sociobiological model.
A Demographic Analysis of Male Life History and Social Structure of Mountain Gorillas
Authors: Robbins Martha M.
Published: April 2008

Twenty-five years of demographic data on free-ranging mountain gorillas (Gorilla gorilla beringei) from the Karisoke Research Center, Rwanda were used to assess male life histories and the variation within the age-graded social structure. Group types include lone silver-backs, one-male, multimale, and all-male groups. Although 60% of gorilla groups in the Virunga population are one-male, a multimale structure may increase chances of survival and future reproductive success for males at three stages of their lives. Infants born in one-male groups appear more likely to die from infanticide than those in multimale groups. Immature males in one-male groups may face decreased future reproductive opportunities compared to males in multimale groups. Adult males in one-male groups lack possible partners for coalition formation during intergroup encounters. Demographic constraints, such as length of time to male maturation, coupled with intense male-male competition for mates may limit the number and duration of groups with a multimale structure. Individuals are not restricted to one group type for their entire adult lives and males that attain maturity in each group type may eventually reproduce. Variation in male reproductive success is based both on length of reproductive tenure and on the number of mates.
Olfactory Preferences in Newborn Lambs: Possible Influence of Prenatal Experience
Authors: Schaal Benoist , Orgeur Pierre , Arnould Cécile
Published: April 2008

The present study examined whether prenatal chemosensory experience influenced chemosensory-based orientation behaviour in newly-born lambs. Two experimental strategies were developed in order: (i) to analyse the responsiveness of lambs to odours extracted from the prenatal environment (experiments 1 and 4) and to odours their were never exposed to (experiment 2), and (ii) to analyse the neonatal consequences of a prenatal exposure to a novel odorant (experiment 3). In experiment 1, when simultaneously presented with amniotic fluid (AF) and distilled water in a double-choice test, lambs displayed a clear attraction to AF. In experiment 3, two groups of lambs received differing exposure to citral in utero: group I lambs were born to ewes fed a citral diet and group 2 lambs were born to ewes never exposed to citral (CI). They were assessed in a double-choice test contrasting CI and AF (experiment 2 indicates that CI was neither attractive nor aversive in naive lambs). Although control lambs showed a clear preference for AF over CI, those exposed to CI prenatally did not orient discriminately to either stimulus, suggesting that prenatal experience with CI may alter postnatal responsiveness to it. Experiment 4 tested the ability of lambs to discriminate between the chemosensory qualities of samples of own vs alien AF; lambs oriented preferentially to their own AF. These findings suggest that prenatal chemosensory experience may be stored by lambs for some time after birth and influence their search behaviour.
Play Signals as Punctuation: the Structure of Social Play in Canids
Authors: Bekoff Marc
Published: April 2008

Actions called play signals have evolved in many species in which social play has been observed. Despite there being only few empirical demonstrations, it generally is accepted that play signals are important in the initiation ("I want to play") and maintenance ("I still want to play") of ongoing social play. In this study I consider whether a specific and highly stereotyped signal, the bow, is used to maintain social play in adult and infant domestic dogs, infant wolves, and infant coyotes. To answer this question the temporal placement of bows relative to actions that are also used in other contexts (dominance or predatory encounters) such as biting accompanied by rapid side-to-side shaking of the head was analyzed to determine if bows performed during ongoing social play are used to communicate the message "I want to play despite what I am going to do or just did - I still want to play". The non-random occurrence of bows supports the hypothesis that bows are used to maintain social play in these canids when actions borrowed from other contexts, especially biting accompanied by rapid side-to-side shaking of the head, are likely to be misinterpreted.
Pod Characteristics of Migrating Humpback Whales (Megaptera Novaeangliae) Off the East Australian Coast
Authors: Brown Miranda , Corkeron Peter
Published: April 2008

The size and sex composition of migrating humpback whale pods were investigated off the east Australian coast. Two hundred and thirty one singletons, 257 pairs, 63 trios, 7 quads and 4 pods containing more than 5 individuals were observed during two land-based surveys carried out throughout the northward migration in 1991 and 1993. Generally humpback whales migrated northward towards the breeding area in pods of I or 2 individuals. In 1992, a biopsy study was carried out throughout the northward and southward migrations. Pods migrating southward (mean = 2.59, SE = 0.19) towards the feeding areas were significantly larger than those travelling north (mean = 1.75, SE = 0.03). The sex of 134 individuals in 63 complete pods was determined by molecular analysis of skin biopsies. Male humpback whales were found in larger pods than females. The most common pod type observed was the male-female pair, which is suggestive of either mating on migration and/or mate-guarding. Males were found associated together frequently. Competitive behaviour was observed during both the northward and southward migrations. The sexing of all individuals within 8 competitive pods indicated that not all contained a female. Although competitive behaviour was observed during the migration, most male-male associations were charactcrised by non-agonistic and occasionally cooperative interactions. We suggest there is a behavioural continuum on migration between the feeding and breeding grounds which is not governed solely by spatial proximity to the terminus. The pod characteristics of humpback whales on their return migration to the feeding grounds showed greatest similarity to those observed on breeding grounds elsewhere. In conclusion, our study showed that the migration of humpback whales is more