bluuebunny/crossref_metadata_2025_split huggingface dataset:
Visual and Acoustic Display in Uca Mordax and U. Burgersi, Sibling Species of Neotropical Fiddler Crabs. I. Waving Display
Authors: Von Hagen Heinrich-Otto 
Published: April 2008

AbstractThe fiddler crabs Uca mordax and U. burgersi, living sympatrically from Guatemala to southern Brazil, were until recently discussed as belonging to only one species, because their similarities refer not only to morphology but also to their waving displays, which were called "indistinguishable". A frame-by-frame analysis of motion pictures taken in Trinidad (W.I.) confirmed the presence of many similarities in respect to the special "jerking" type of waving display, the mean duration of routine waves, the effect of increasing excitation, the pattern of leg-waving and the presence of a "precursory" downstroke" of the major cheliped. However, a closer analysis of certain components or elements of the display yielded various interspecific differences. In burgersi there is the tendency to omit the precursory downstroke and to extend all motion components at the cost of all kinds of pauses, while in mordax the contrary is true. Furthermore, the movements of the minor cheliped show a different pattern in the two species. The differences found are discussed in respect to differences in the allometry of the major cheliped and from an evolutionary point of view. It is concluded that the waving display of mordax represents the more ancestral type. The role of the waving display as a possible means of reproductive isolation will be discussed in part II of this study dealing with the acoustic display.
Optimisation of Nut-Cracking With Natural Hammers By Wild Chimpanzees
Authors: Boesch Christophe , Boesch Hedwige 
Published: April 2008

AbstractThe chimpanzees of the Tai National Park, Ivory Coast, use sticks and stones to open 5 different species of nuts. In spite of an unfavourable availability of the material in the forest, the animals choose their tools adaptively. For cracking harder nuts, they use harder and heavier tools and transport tools more often and from farther away. Some aspects of the evolution of tool-use in primates are discussed.
Oestrous Behaviour and Female Choice in the African Elephant
Authors: Moss Cynthia J. 
Published: April 2008

Abstract1. During the course of an eight year field study of African elephants in Amboseli National Park, Kenya, from September, 1972 to December, 1980, females were seen exhibiting oestrous behaviour on 154 occasions, during which 43 copulations were witnessed. 2. Five categories of oestrous behaviour are described: a) wariness, b) the oestrous walk, c) the chase, d) mounting, and e) consort behaviour. 3. The oestrous behaviour as described was found to be temporally associated with ovulation, as judged by conceptions, in 70.7% of 58 cases. 4. The duration of oestrous periods is estimated at 2-6 days. 5. On average Amboseli females conceived once every 5 years and for each of these conceptions the female may only have been in oestrus once. 6. Evidence from the Amboseli study suggests that some females may exercise choice in mating partners. For example, females were able to elude their pursuers in 69.4% of all chases (n = 134). Observation of female behaviour during oestrus suggested that some females preferred to mate with males in the largest size class, particularly those in musth. 7. Two possible short-term advantages to females exercising choice in mating partners are suggested: a) avoidance of harassment from other bulls; and b) Large males in musth may be more likely to impregnate a female. 8. A possible long-term advantage to mating with a Large, and therefore older, male could be his ability to pass on a trait for longevity. 9. Although females may be exercising choice among the size/age classes, male-male competition among the Large males may override female choice on the individual level.
Chaffinch Song Repertoires and the Beau Geste Hypothesis
Authors: Dawson S.M. , Jenkins P.F. 
Published: April 2008

AbstractThe aim of this investigation was to determine to what extent song repertoires and singing behaviour of chaffinches (Fringilla coelebs) evolved as a means by which resident birds deceive intruders into overestimating the density of residents, making the area appear less suitable for settlement. (1) The chaffinches studied did not show a significant tendency to change song posts synchronously any more than would be expected by chance. (2) Approximately 90% of song type/song post changes were asynchronous. (3) Half of the birds did not repeat their song types with equal frequency, nor did they distribute their singing effort evenly over all the song posts. (4) The degree of similarity between song types in the same repertoire and the degree of similarity between song types from different individuals were not found to be significantly different. (5) No correlation between song rate and repertoire size was found, but it was concluded that seasonal biases strongly restricted this facet of the investigation. On the basis of these findings it is concluded that the evolution of repertoires and singing behaviour in chaffinches seems unlikely to have occurred in conformity with the Beau Geste hypothesis.
Alternative Mechanisms of Social Organization in Monkeys
Authors: Rowell T.E. , Olson D.K. 
Published: April 2008

AbstractObservations on a captive group of patas monkeys were supplemented with field observations to analyse the process by which a gregarious animal keeps track of the position and activity of other group members and regulates the distance between them and itself. This process can take place without the exchange of specialised signals (displays) and is described as a mechanism of group organisation alternative to a mechanism based on the exchange of displays. Displays and formalised interaction patterns can provide additional, complementary information, especially about transient features of social organisation.
Determinants of Dominance in Male Sticklebacks (Gasterosteus Aculeatus L.)
Authors: Bakker Th C.M. , Sevenster P. 
Published: April 2008

AbstractWhen two males of the three-spined stickleback (Gasterosteus aculeatus L.) in reproductive condition are placed in a tank of small size, one becomes dominant over the other in a very short time. In this way a group of isolated reproductive males were tested pairwise on their capacity to become dominant. It appeared that the males could be arranged in a linear order of dominance. Their rank was to some extent correlated with their territorial aggressiveness as assessed in other tests. Their experience in previous dominance tests played a more important role. The brightness of their colouration, however, was probably the most consistent and decisive determinant of dominance. The interaction of colour and experience could be traced in the outcome of the dominance tests. The occurrence of roundabout fighting is discussed.
Clasping Behaviour in Macaca Tonkeana
Authors: Thierry Bernard 
Published: April 2008

AbstractClasping behaviour was studied in two groups of Macaca tonkeana, one being confined in a cage, the other living in a half-hectare park. Five patterns have been distinguished: grasping the hindquarters, grasping, reaching around, embracing and hugging. Clasping may occur in three contexts: greeting, aggression and sexual harassment. There seems to be no direct relationship between context and pattern of clasping. However, there is substantial variation in form and context according to age- and sex-class. Females are the individuals mostly involved in clasps, being initiators as well as receivers; adult males also initiate numerous clasps but receive few. Adult and subadult males especially use grasping the hindquarters while other age- and sex-classes more often use reaching around. Clasping in aggression is more characteristic of females than males. Several behaviours may be associated with clasping. The accompanying behaviours are more frequent in initiator than in receiver. Clasp is often followed by social grooming, mount, wrestle or another clasp. The results of this study in Macaca tonkeana may be compared with information from other studies of non-human primate species. This allows one to draw several conclusions: 1. Frequency, form and distribution of clasping vary from one species to another. There is great variation in certain species, for instance, Macaca tonkeana. 2. Several behaviours usually accompany clasping and may modulate its meaning. 3. Clasping behaviour shows many similarities to mounting behaviour. Although these two behaviours have different origins, they have acquired similar social functions. 4. Clasping plays a prominent role in control of aggression. In Macaca tonkeana, this behaviour is especially used in appeasement (an individual receiving aggression clasps its aggressor during the aggression), reconciliation (an aggressor clasps its antagonist after the aggression) and non-agonistic protection (a third individual intervenes in an agonistic interaction by clasping the aggressor). Non-agonistic protection is an interaction which was until now described only in chimpanzees.
Recognition of Conspecifics and Sex By Territorial Males of the Social Wasp Polistes Fuscatus (Hymenoptera: Vespidae)
Authors: Post David C. , Jeanne Robert L. 
Published: April 2008

Abstract
Territorial males of Polistes fuscatus (subspecies variatus) respond to intruders with a chain of behavior of increasing intensity as follows: (1) no reaction, (2) orient, (3) pursue, (4) grasp, and (5) either grapple (with male intruders) or attempt copulation (with females). In the laboratory test objects combining different visual, chemical, and behavioral stimuli were tethered and waved in front of perched territorial males to determine the role of each in eliciting a male response. All test objects elicited an orient response. The overall color or contrast with the background and shape of the test object had little effect on male response. The black and yellow banded coloration characteristic of conspecifics released pursuit and grasping behavior, while chemical cues in combination with the banded coloration released grasping and grappling or attempt copulation. Recognition of sex was based on chemical cues and not on the sexually dichromic coloration. From this and previous studies we conclude that the black and yellow banded coloration of conspecifics is the most important visual stimulus for long-range attraction (> 15 cm) of males, while at close-range or on contact a cuticular surface pheromone and a sex pheromone from the venom are important in the recognition of conspecifics and for discrimination between the sexes.
Measuring the Strength of Social Bonds: Experiments With Hand-Reared Goslings (Anser Indicus)
Authors: Lamprecht J. 
Published: April 2008

AbstractAllogrooming, dueting and other behaviours observed only between pair or group members are often said to reinforce or strengthen social bonds, yet the strength of these bonds was not measured independently. 'Bond strength' should reflect the stability of an attachment relationship and thus the probability of a permanent separation from the partner. The latter is a function of opportunity or external force as well as of an internal 'divorce tendency'. Only the divorcc tendency is inversely related to that motivational variable which can be called 'bond strength'. To find a behavioural measure of individual divorce tendency, the relationship of hand-reared bar-headed goslings (Anser indicus) to their human foster parents was investigated in four experiments. The following results were obtained: (1) The subjects (n = 18) significantly preferred their own, familiar foster parent (Hp) to a less familiar person (Hu). (2) This was also true when the Hu was the preferred Hp of another group of goslings, indicating that familiarity and not his suitability as a 'goose parent' is the relevant factor. (3) Alone with one person on a lawn, all goslings (n = 12) also maintained proximity when this was an Hu, indicating a bond to him also. Median distances maintained to Hp and Hu did not differ significantly, and were therefore no indicators of a gosling's preference. But the distress calling rate was significantly higher and the feeding rate significantly lower when a gosling was with an Hu than when with its Hp. (4) Distress calling rate in the presence of a stationary person was also a good indicator of a gosling's (n = 15) tendency to leave him and follow a slowly moving stranger. Approaches towards the stranger were significantly longer when the stationary person was an Hu than when it was the Hp. The amount of distress calling in the presence of an Hu was positively correlated (p<0.01) with the distance that the subjects later moved towards the stranger. The distress calling rate therefore is a good relative measure of a gosling's tendency to abandon a particular object, this tendency reflecting what we may call the strength of a bond or attachment.
Vocal Communication in Raccoons (Procyon Lotor)
Authors: Sieber Otto J. 
Published: April 2008

AbstractThe study describes structure, ontogeny and contexts of raccoon (Procyon lotor) vocalizations and investigates whether structure and motivation interplay in the way predicted by general motivation-structural rules (MORTON, 1977, 1982). Observations during a full reproductive cycle in a mixed group of captive raccoons indicate that they use an elaborate vocal repertoire including 13 calls (Table 1). Two calls are tonal (whistle, squeal), three noisy (snort, bark, growl); four have a mixed structure (cry, screech, gecker, grunt) and four have pulsed syllables (chitter 1, chitter 2, churr, purr). Though some calls grade into one another, the repertoire is largely discrete. Three calls are present at birth and form the nestling repertoire. The adult repertoire gradually develops through the time of weaning (Fig. 2). Several calls are characteristic for the sexual and parental phase. Most calls are associated with one or a few contexts (Table 2). Four calls are utilized by animals while distressed and have an attracting effect on others. Four calls express hostile motivation and repel other animals. Five calls are used by animals approaching another or having body contact; they serve in promoting or maintaining contact. Calls used in similar contexts show remarkable structural similarities. Distress calls are tonal or mixed, hostile calls noisy in accordance with motivation-structural rules. Contact calls deviate in being noisy and low in basic frequency. Possible reasons are discussed. A comparison of the vocalizations in other carnivores reveals that the structure-motivational pattern found in raccoons is a wide-spread phenomenon in carnivores.
Long-Range Vocal Interactions Between Groups of Gibbons (Hylobates Lar)
Authors: Raemaekers Patricia M. , Raemaekers Jeremy J. 
Published: April 2008

Abstract
We report on long-range duet interactions among twelve wild groups of lar gibbons (Hylobates lar) in Thailand. Statistical analysis demonstrates that groups were more likely to respond with an answering duet to a duet sung by a neighbouring group than to one sung by a non-neighbouring group in the population. A distinctive pattern of response among neighbours was to wait until a neighbouring group had finished its duet before immediately answering with a duet, resulting in avoidance of overlap between the two duets. Non-neighbours did not exhibit this pattern. The effect is shown to be due solely to neighbour status and not to the degree of mutual audibility of the duets. There was no evidence that, when duets overlapped, the first group to sing modified the length of its duet in response to the second duet, whether given by a neighbour or by a non-neighbour. In general, among those groups which responded to one another's duets, there were no identifiable leaders and followers: the order of duetting groups was random. We discuss why neighbours interact more by duet than do non-neighbours, and consider what may be the functions of avoiding overlap of duets.
Breeder-Helper Conflict in a Cichlid Fish With Broodcare Helpers: an Experimental Analysis
Authors: Taborsky Michael 
Published: April 2008

AbstractThis paper reports an experimental analysis of conflicting interests in the cooperatively breeding Lamprologus brichardi (Cichlidae). Helpers clearly prefer to stay in the family territory rather than leave for an aggregation of same-size young or for an unoccupied area-even when their chances of reproducing independently are superior to those in the field. Helpers usually attain independence when the breeders force them to leave the territory. Breeders' toleration of helpers depends on the stage in the reproductive cycle, the size of helpers and the need for helpers. Large, previously expelled helpers are reaccepted when competition is increased. In these circumstances breeders prefer their own former helpers to strange young. Experimental and field evidence suggests that 3 factors are ultimately important for the breeder/helper relationship: reproductive parasitism by mature helpers, eventual cannibalism on breeders' eggs and competition for shelter within the territory. A graphical model shows how the initially common interests of breeders and helpers develop divergently when helpers reach the size at which they become sexually mature and less susceptible to predation. Large helpers pay to stay. The relationship of breeders and large helpers meets the criterion of reciprocal altruism.
Responses of Lambs To Model Ewes
Authors: Shillito Walser Elizabeth , Walters E. , Hague P. , Williams T. 
Published: April 2008

Abstract
Life sized models of sheep were used to determine the importance of sound and movement in eliciting orientation and approach of lambs. Dalesbred and Jacob lambs were tested at 3 weeks of age with two models, one of which appeared to be grazing while the other moved its head or bleated or both bleated and moved. Lambs were tested twice; their behaviour was recorded to note 1) time of orientation to models and approach; 2) positive or negative response; 3) approach within 2 m of the models. The Dalesbred lambs ran faster than the Jacobs towards the models, and more Dalesbreds responded positively on the second test. Both breeds responded more quickly to the vocal models than to the silent models; there was no difference in time of response to moving and non-moving models. 90% lambs approached and looked at the models on the first test, 51 % responded on the second test. All lambs that responded went up close to bleating models, but not to moving models. Movement did not increase attraction and seemed to deter close investigation, whereas vocalisation made the models most attractive to the lambs.
The Influence of Weather On Incubation Scheduling of the White-Rumped Sandpiper (Calidris Fuscicollis): a Uniparental Incubator in a Cold Environment
Authors: Cantar Ralph V. , Montgomerie Robert D. 
Published: April 2008

Abstract
We studied the incubation scheduling of 8 white-rumped sandpipers (Calidris fuscicollis), a species in which only the female incubates. Because the female is small and nests in the high arctic, these birds are probably under more cold stress than birds nesting in the temperate zone. We examined the individual and collective effects of several weather variables on a female's incubation behaviour to ascertain what amount of the variability within a day was directly attributable to weather conditions. Birds made an average of 25.1 off-nest trips each day, averaging 10.5 min each. This resulted in spending, on average, 82.5% of their time incubating eggs. There was a clear within-day cycle in incubation scheduling; birds made more and longer trips in the middle of the day and, as a result, spent more total time off the nest in that period. Birds adjusted their hour-by-hour schedules to weather largely by altering the number of trips made, and less so by adjusting trip length. There was a circadian rhythm in recess time/h, explaining at least 11% of the variation in recess time/h. When the circadian rhythm was controlled statistically, weather accounted for an average of 38% of the explainable variation in recess time/h. The relative importance of each weather variable on the recess time/h was (in descending order of importance): wind speed, air temperature, solar radiation, barometric pressure, and relative humidity. Weather (primarily wind speed and temperature) exerted its strongest effects early and late in the bird's active day (0400-2300 h). On cold and windy days, birds increased the time spent on their nests early and late in the day, and made more trips than usual in the middle of the day, when air temperature was highest. We suggest that the incubation scheduling of these birds conformed to the long-term predictability of the daily weather cycle by following a circadian rhythm of behaviour modified by a response to concurrent weather that would have reduced egg cooling.
Feeding Strategies of Male and Female Adult Herring Gulls (Larus Argentatus)
Authors: Greig S.A. , Coulson J.C. , Monaghan P. 
Published: April 2008

Abstract
This paper examines the foraging behaviour of adult male and female herring gulls at refuse tips during winter. Although the majority of herring gulls were either on the tip or nearby for much of the daylight period, an individual male or female fed at the tip for only 30 minutes per day. Three types of feeding were distinguished: (a) undisturbed primary feeding on freshly dumped refuse; (b) disturbed primary feeding where the gulls fed whilst a bulldozer was moving the refuse; and (c) secondary feeding on dispersed refuse partially covered with earth. During primary feeding the herring gulls fed at high density and the feeding flock comprised 73% adults whilst during secondary feeding they were at low density and the flock contained only 25 % adults. A comparison of disturbed and undisturbed primary feeding showed that the birds dipped for food from the air in the former but searched for food on the ground in the latter. This resulted in eight times more encounters per individual and much greater competition in undisturbed feeding. Proportionally more adult male than female herring gulls participated in undisturbed (i.e. competitive) feeding, whereas the reverse was true of disturbed feeding. These differences were greatest in the first half of the winter (i.e. October-mid-December). There were no differences in the sex-ratio of those participating in secondary feeding. During undisturbed primary feeding adult females had higher pecking and walking rates and lower encounter rates than males. Males obtained at least a fifth of their food by attacking and displacing other feeding herring gulls, three times more than females. Female herring gulls fed more often on the edge of the refuse pile where competitive interactions were less frequent but also where foraging success was lower. As the undisturbed feeding bout progressed, attack rates of males increased and their swallowing rate was sustained. In contrast, the attack rates of females decreased as did the swallowing rates. The proportion of females present also decreased, suggesting that some females were responding to the increased levels of aggression by leaving the feeding area. Refuse tips provide a variety of feeding opportunities. In a competitive feeding situation the smaller female herring gulls are disadvantaged by the dominance of males. In disturbed feeding they are able to compensate to some extent because their smaller size results in greater manoeuvrability.