bluuebunny/crossref_metadata_2025 huggingface dataset:
The Spread of Food Producing Techniques in a Captive Flock of Jackdaws
Authors: Wechsler Beat
Published: April 2008

The spread of techniques to get peeled oats from a food dispenser was observed in a captive flock of 28 jackdaws (Corvus monedula) in two replicates. It was hypothesized that the quality of the social relationship between two jackdaws could affect the probability of social learning within that dyad. Therefore technique acquisition of socially bonded dyads (pairs) and socially indifferent dyads (non-pairs) was compared. The results can not falsify the hypothesis of individual learning regardless of the partner's knowledge about a successful technique. Pair members did not learn faster from each other than members of non-pair dyads. Pair members did not preferentially acquire the same technique. There was no indication that the rate of technique acquisition within the flock increased with the number of established technicians. Qualitative observations support the explanation of individual trial-and-error learning.
Food Competition in Brown Capuchin Monkeys (Cebus Apella): Quantitative Effects of Group Size and Tree Productivity
Authors: Janson Charles H.
Published: April 2008

The effects of group size and fruit availability in tree crowns on per-capita food intake was examined for wild brown capuchin monkeys living in groups of 3-12 individuals. Per-capita feeding time was nearly exactly inversely proportional to group size in small-crowned trees with little fruit, but was essentially independent of group size in large-crowned trees with abundant fruit. Despite the use of such productive trees, per-capita feeding time in the average tree visited decreased by 50% over a 4-fold range of group sizes. This cost of indirect food competition in large groups was not compensated by increased rates of ingestion, preferential use of large trees, of a higher rate of fruit tree encounter per distance travelled. Instead, foraging effort (distance travelled, number of minutes devoted to foraging, total activity minutes per day) increased at large group sizes. Estimates of total energy intake and expenditure suggest that net energy gain is constant for individuals in group sizes of 5-12. I suggest that the upper limit to group size is set by the daylength available for foraging in large groups. Aggression in food trees increased in frequency in larger groups, but the relative feeding rates of dominants and subordinates of a given rank did not appear to depend on group size. Observed decreases in per-capita food intake due to either indirect or aggressive food competition within large groups are substantially greater than the 4% gain in mean food intake that large groups achieve by displacing smaller groups from fruit trees.
Food Competition and Foraging Party Size in the Black Spider Monkey (Ateles Paniscus Chamek)
Authors: M M.
Published: April 2008

In Ateles, individuals forage for fruit in subgroups of unstable membership. The size and composition of these foraging parties are highly variable. Data from my long-term field study of a population of black spider monkeys in Peru show a strong positive correlation between the average size of these parties and the number and size of trees currently producing fruit in the environment. This correlation appears to be driven by intragroup feeding competition, since individuals in larger parties showed substantially lowered feeding efficiencies, as measured by increased daily ranges and decreased time spent feeding. Patch size and patch density, which jointly determine fruit abundance, interact to determine foraging party size, apparently by the following mechanism. The number of spider monkeys that can feed within a particular patch is limited by the size of that patch. When patches are close together (i. e. high patch density) individuals in excess of this limit are able to feed in nearby patches and thus maintain contact with the other members of their foraging party. When patch density is low, the increased travel costs associated with such a strategy become prohibitive and foraging parties are smaller than or equal to the number of individuals able to feed within a single patch. Females that are routinely excluded from the best feeding sites may have reduced reproductive success because of their low priority of access to resources. These data provide a quantitative link between two ecological variables (resource patch size and density) and fission-fusion social organization in the spider monkey.
Feeding Competition and Patch Size in the Chimpanzee Species Pan Paniscus and Pan Troglodytes
Authors: Wrangham Richard W. , White Frances J.
Published: April 2008

The relative importance of feeding competition in Pan paniscus and Pan troglodytes schweinfurthii is examined in an attempt to understand the major differences in social organization of the two species. P. paniscus at Lomako is characterized by a stronger tendency for association among females than among female P. troglodytes at Gombe. Party size in P. paniscus is dependent on patch size. Feeding competition was more important in small patches than in large patches. The total amount of feeding time by a party in a patch (chimp-minutes) was a measure of patch size that was available for both chimpanzee species. P. paniscus was found to have larger party sizes and to use larger food patches than P. troglodytes. The importance of dispersed ground foods for each species of chimpanzee was compared and, although the results are not conclusive, they indicate that this type of food was equally important in the diets of both populations. Two hypotheses of the ecological basis for differences in social structure are compared in light of this evidence.
Benefits, Costs, and Determinants of Dominance in American Black Ducks
Authors: Hepp Gary R.
Published: April 2008

Behavioural dominance was studied in captive American black ducks (Anas rubripes) during October-December 1984. Eighty ducks were marked individually, and groups of 10 ducks consisting of 5 adults (3 males and 2 females) and 5 juveniles (3 males and 2 females) were assigned to each of 8 experimental pens. Ducks in 4 pens received an ad libitum diet, and ducks in the other 4 pens were given a restricted diet. Dominance structure within pens was linear. Adults were dominant to young, and body mass had no influence on dominance rank. The effect of sex on dominance rank was age-specific. Adult males were dominant to adult females and to young black ducks of both sexes; however, dominance rank of young males did not differ from adult or young females. Paired adults were dominant to unpaired adults and to young individuals that were either paired or unpaired. Paired young black ducks were similar in dominance rank to unpaired adults and unpaired young indicating that pairing did not make these individuals more dominant. Ducks on the restricted diet gained less body mass than ducks on the ad libitum diet (HEPP, 1986), but dominant and subordinate black ducks within treatment groups experienced similar changes in body mass during the early winter. Dominant black ducks interacted more frequently and were more likely to form pair bonds than subordinates, thus higher energy costs of dominant individuals may explain the poor relationship between physical condition and dominance rank. There was a significant positive association between the dominance ranks of pair members.
Vocal Mimicry and Interspecific Aggression in Songbirds: Experiments Using White-Crowned Sparrow Imitation of Song Sparrow Song
Authors: Baptista Luis F. , Catchpole Clive K.
Published: April 2008

A series of playback experiments was carried out to determine whether territorial male song sparrows could discriminate between their own species song, and the same song produced by a white-crowned sparrow. In two out of three measures of response, the males did not discriminate between model and mimic song. In constrast, most males showed no response to control white-crowned sparrow song, although two individuals showed a strong interspecific response. Other examples of interspecific aggression were also detected during the experiments. The results are discussed in relation to recent studies on interspecific song learning and the competition hypothesis of vocal mimicry in songbirds.
Distance Regulation of Hand-Reared Goslings (Anser Indicus) To an Unresponsive Parent: a Study of the Short-Term Dynamics of Attachment
Authors: Lamprecht Jürg
Published: April 2008

This study investigated the ways in which young goslings contribute to the proximity between parent and offspring in geese. It sought to detect the rules governing excursions of hand-reared goslings (Anser indicus) from a stationary and non-responding human 'parent' on a large lawn. Distance to the parent and behaviours (distress calling, feeding and others) were monitored during 149 30-min-sessions of 28 goslings (7-19 days old), most of which were accompanied in some sessions by a sibling. Of two additional experiments, one demonstrated the positive effect of sibling group size on maximum distance from the parent, the other showed that distress calling induced by forced separation from the (human) parent was reduced by the presence of siblings. Excursion analysis revealed that the probability of returning to the parent was independent of time and distance. This allowed rejection of some earlier models of excursion control. Only sudden disturbances in the environment (occurring at random with respect to the start of an excursion), forced separation from the parent, and-similarly-the parent's walking away were found to elicit approach to the parent. The speed of leaving the parent was also independent of time and distance. Thus distance was not limited by an increasing locomotor tendency to return. But rate of distress calling increased with distance. Two causes for the goslings' departures were identified: 1) parental non-signalling (by the "mute" parent), which aroused a tendency "to go home", and 2) hunger combined with the tendency to forage in a fixed direction. Return probability, speed of leaving and distress call rate at any given distance were lower when a gosling was accompanied by a sibling, apparently because the social feedback received from the sibling compensated for the parent's non-signalling. In spite of behavioural tendencies which lead a gosling to potentially unlimited distances from its parents, it will not normally get lost, as it returns whenever alarmed or when the parents walk away, and because goose parents tend to join a gosling distress calling at a distance.
Condition Changes and Choice of Social Environment in African Buffalo Bulls
Authors: Prins H.H.T.
Published: April 2008

1. The social behaviour of the African buffalo (Syncerus caffer) was studied between 1981 and 1985 in Lake Manyara National Park, northern Tanzania. Emphasis is placed on the relationships between adult bulls (i.e. older than 7 yrs). 2. These bulls were transient members of the buffalo population of the study area. At any time ± 150 adult bulls were in the area. During the study period 240 individual bulls were recognized, and the number of the 'bull pool' during this period was estimated to be 630. 3. Every few weeks, the bulls switched between the herd state and bachelor state, and wandered from herd to herd, presumably in search of oestrus cows. 4. They did not form stable associations, and when bachelor, they preferentially associated in temporary groups of 3 to 5 bulls. 5. Adult bulls engaged in sparring and showed dominance interactions very rarely. In a dyadic encounter, dominance interactions were only observed between bulls of the same body condition. Encounters involving individuals in different condition resulted in dominance being established without interaction. Fighting is extremely rare and likely to be lethal to both opponents. 6. The switching between both social environments was related to condition loss in the mixed herd and to condition gain in the bachelor state. This resulted in a 'rotating dominance hierarchy'. The bachelor phase is an essential part of the breeding cycle of an adult bull. 7. The necessity of a bachelor phase to recoup body condition may well be a general feature in mammalian species with long breeding seasons.
Optimistic and Pessimistic Fruit Flies: Evaluating Fitness Consequences of Estimation Errors
Authors: Roitberg Bernard D.
Published: April 2008

I began with an observation that there exists consistent variation among fruit-parasitic female flies (Rhagoletis pomonella) with regard to search time allocation. In essence, populations appear to be composed of flies that are "optimistic" and "pessimistic" about their chances of locating other higher quality patches. I posed the question "how can such variation be maintaned over time?". To answer this question I developed stochastic, dynamic, state-variable model that considered patch emigration decisions by individuals as a function of: (1) current patch quality, (2) average patch quality, (3) density of patches, (4) time of day, and, (5) egg load. The model was then altered to allow for optimistic and pessimistic estimates of patch availability. The optimal behaviour for such flies was then solved. Results obtained showed that optimists move more often within trees and pessimists move more frequently among trees. Further, calculation of daily reproductive output showed that both optimists and pessimists performed nearly as well as flies with errorless estimates of patch availability so long as over and under-estimates were moderate. This is because of the interaction between egg limitation, host availability and time limitation. When patch estimate errors were large (e.g. 90%), however, pessimists performed less well than optimists. These results allowed me to derive fitness curves for optimists and pessimists. These curves were then used to predict the distribution of search allocation by flies in the field. Predictions as to the shape of the distribution were consistent with field data (i.e. optimists are over-represented in samples).
Family Planning in the Kestrel (Falco Tinnunculus): the Proximate Control of Covariation of Laying Date and Clutch Size
Authors: Meijer Theo , Daan Serge , Hall Michael
Published: April 2008

The time in spring when a male kestrel rapidly increases his daily hunting time and his hunting yield, and thereby the amount of food delivered to the female, determines the date when she lays the first egg. Food experiments in free-living and captive kestrels gave a significant advance in laying date. Clutch size, which decreases with progressive laying date, did not change independent of date in response to food manipulation. These effects are in agreement with most other feeding experiments. Photoperiod experiments in kestrels advanced the reproductive cycle in constant long days, and a similar seasonal decline in clutch size was found. It seems that there is an internally preprogrammed decrease in clutch size within an annual "reproductive window". A proximate control model for the seasonal decline of clutch size is proposed, modified from an earlier model by HAFTORN (1985). This incorporates an increasing tendency to incubate the first eggs with progression of the season, an egg contact-incubation positive feedback loop, and the resorption of further follicles in the ovary when the laying female incubates 50% of the time. This follicle resorption fixes the clutch size ca. four days before the last egg is laid. the 50% incubation level is reached earlier in late females and consequently resorption starts earlier and the resulting clutch is smaller than in early females. Experiments in kestrels with removal and addition of eggs, in combination with measurements of incubation behaviour are discussed in relation to the model. Plasma prolactin data of female kestrels show that this hormone is a serious candidate for a physiological component relaying time of year in our model for clutch size regulation.
Dod, Sex, Time, and Effort in a Small Mammal: Energy Allocation Strategies for Survival and Reproduction
Authors: Perrigo Glenn
Published: April 2008

The relationship between food energy and work effort (foraging) is crucial to small mammals such as the house mouse (Mus domesticus). Energy allocation processes were studied by using a special caging system in which animals were required to work for 45 mg food pellets by running on an activity wheel. Two experimental themes were investigated: 1) When weaning female mice were forced to work harder for less food, their highest energy allocation priority was to maintain fat reserves; body growth was next in importance while achieving puberty had the lowest prority of all. The relative insensitivity of fat deposition to high foraging costs suggests a strategy for survival whereby dispersing animals maintain emergency fat reserves at the expense of growth and fertility. In male mice, however, reproductive development is independent from body growth. Both sexes employed fundamentally different energy allocation strategies during peripubertal development. Some of these sex differences were gonad-dependent, while others were not. The time spent foraging while exposed to cold ambient temperature is also critical during peripubertal development, and this relationship probably determines whether or not house mice will breed continuously or seasonally in feral habitats. 2) Deer mice (Pemmyscus maniculatus) and house mice were challenged to produce litters at increasingly greater work requirements. Deer mice supported heavier litters and produced more pups at weaning than house mice, mainly because deer mice were more efficient at food use. With regard to circadian organisation, deer mice accomplished almost all of their locomotor tasks during darkness while house mice exhibited day-to-day flexibility in locomotor activity, especially during lactation. Deer mice attempted to wean five or six pups, regardless of how severe the feeding conditions; however, pups became progressively stunted as females worked harder and obtained less food. In contrast, house mice had more pups at birth than deer mice, but females killed and cannibalized offspring throughout the first 12 days of lactation. Most surviving house mouse pups thus attained similar body weights at weaning. These divergent energy allocation patterns may reflect strategies arising from opportunism (house mice) versus seasonality (deer mice).
Copying the Mate Choice of Others? Observations On Female Black Grouse
Authors: HÖGLUND Jacob , Alatalo Rauno V. , Lundberg Arne
Published: April 2008

It has been suggested that the non-random mating often observed in lekking species is a consequence of either male-male competition or active female mate choice. Here we show that the highly skewed mating distributions observed in a black grouse lek in three years were indeed different from random expectations. We suggest that females copying the mate choice of others enhance this skew. Observations in favour of copying are: females pay multiple visits to the lek during several days; females arrive and move in bands which makes it possible to observe the visits to male territories and matings of other females; in the main lek in the study area, males often mated in sequence indicating that by being visited by many females and by mating the attractiveness of males increased. However, this last effect was only evident in one of the years of the study, and only on the largest lek which had exceptionally many female visits this year. In leks with a smaller number of visiting females, copying, even if present, is difficult to detect without experiments since almost all females tend to copulate with the top-male.
Territoriality in a Terrestrial Salamander: the Influence of Resource Quality and Body Size
Authors: Mathis Alicia
Published: April 2008

Intraspecific interference competition associated with territoriality has been documented in laboratory studies of the red-backed salamander, Plethodon cinereus. I used laboratory and field experiments to study the effect of resource quality and body size on such competition. In an experiment in southwestern Virginia, cover objects (e.g., logs) from which the resident salamanders were removed were invaded significantly more often than cover objects from which the resident salamander was not removed. These data provide the first direct test of territoriality for a salamander in a natural habitat. Newly invading salamanders were significantly smaller than the original territorial residents. Therefore, large body size is an advantage in territorial encounters. Because cover objects are important resources for terrestrial salamanders, characteristics of the cover object may contribute to territory quality. In an experiment conducted during warm summer weather at the Virginia site, soil temperatures under large cover objects were significantly cooler than those under small cover objects or under the leaf litter. Large cover objects may therefore benefit the salamanders by providing a buffer zone between the salamander and extreme environmental temperatures on the forest floor. In both laboratory and field experiments, when salamanders were offered a choice between large and small cover objects, both large and small salamanders exhibited a significant preference for large cover objects. Also I censused cover objects in a natural mixed hardwood forest habitat during courting and noncourting seasons and, for both seasons, I found a significant positive correlation between the body size of the salamander and the size of the cover object that it occupied. I conclude that, in this natural forest habitat, there is intraspecific competition for high quality cover objects and larger individuals are more successful competitors than smaller individuals.
Agonistic Communication in Social Species: What Is Communicated?
Authors: Senar J.C.
Published: April 2008

Relationships between displays used in agonistic encounters, the next behaviour of the reactor, and the actor's subsequent response, are analysed in captive siskins (Carduelis spinus). A three-way independence test showed that the different displays are associated with different replys. Factorial Analysis of Correspondences showed that 76% of the variability in the displays could be explained by variation in the tolerance of the actor to the presence of conspecifics: certain displays led to submissive or non-aggressive responses by the reactor which led to non-aggressive behaviours by the actor, whereas others frequently provoqued an attack, which usually led to a retaliatory attack by the actor. The degree of caution in the response appears to be the other factor that modulates the reactor's subsequent response. This degree of caution appears to be directly related to the relative dominance status of the contestants. These results support the view that in highly social species the aim of agonistic displays is not necessarily to drive opponents away, since this may be costly for both contestants. Agonistic communication in these situations should not be seen as an "auction" to determine who will obtain the resource, but as a warning, in which the actor gives information on how tolerant it is to the close presence of the conspecific and what behaviours it will allow. Depending on its status and behaviour, the second bird may be tolerated, but if it behaves in a "dangerous" way, the actor would attack.
Ontogeny of Fish Capture and Ingestion in Four Species of Garter Snakes (Thamnophis)
Authors: Halloy Monique , Burghardt Gordon M.
Published: April 2008

The feeding behaviour of four species of garter snakes (Thamnophis butleri, T melanogaster, T. radix, and T sirtalis) was observed in an attempt to determine differences across species and among age groups with respect to capturing, handling and swallowing large and small fish. Although belonging to the same genus, the four species differ widely in habitat and prey preferences (T. butieri being recognized as an earthworm specialist, T melanogaster as an aquatic specialist, and the other two species as generalists). Overall, feeding patterns were quite similar across species following a general sequence of capturing fish, maneuvering the jaws to either the head or tail of the fish (the head being "chosen" more often), and swallowing it. Head-first ingestion was related to prey size: the larger the fish the greater the probability the snake would ingest it head first. When this behaviour was analysed more closely, species and age differences emerged. Adults were more efficient at capturing and ingesting fish head-first and took less time to handle and swallow their prey than did juveniles. This difference was not as marked in the two specialist species as in the two generalist species. Considering differences within species and age classes with respect to their handling behaviour of either a large or a small fish, T melanogaster handled both sizes of prey in a time period that was not significantly different, T. butleri took significantly more time to handle a large fish whereas T radix and T. sirtalis took considerably more time to handle a large fish as newborns but not as adults. These results support field observations that T. melanogaster is an aquatic specialist, T. butleri, an earthworm specialist, and the other two species, generalists. In spite of the similarities between the two generalist species, similarities were also found between T. butleri and T. radix which are believed to the taxonomically related.
Lamb's Bleats: Important for the Establishment of the Mother-Young Bond?
Authors: Nowak R.
Published: April 2008

Border Leicester x Merino (BL x M) lambs can discriminate between their own and alien mothers better than Merino (M) lambs when born to the same breed of dam (M). The behaviour of newborn lambs was therefore observed in different situations to investigate the reason for these better discriminative abilities of the BL x M lambs. In a first experiment lambs were removed from the ewe at birth and tested for 2 h under one of the following conditions: 1) reunited with its dam, 2) in the presence of a stationary model, 3) isolated. Overall the ewe had a stimulating effect on the motor activity of the neonate and a quietening effect on its vocal activity when compared to the other 2 groups, but these effects differed according to the genotypes. When isolated or in the presence of the model, BL x M lambs stood for the first time later than M lambs and spent less time standing and exploring the environment. In both situations BL x M lambs vocalised less than M lambs. When mothered, BL x M lambs stood up and found the teat later than M lambs but their motor and exploratory activity did not differ after 2 h of observation. However, mothered BL x M lambs were far more vocal than mothered M lambs. This suggests that BL x M lambs establish better communication with their dams. A second experiment was carried out on M lambs to investigate the existence of a relationship between the vocal activity of the neonate and the development of a bond with the mother. Results showed that the lambs that were the most vocal at birth also had the best performances in a test of mother discrimination at the age of 12 h. It was concluded that early communication between the ewe and her young probably plays a role in the establishment of a preferential bond.
Comparative Fine Structure of Action: Rules of Form and Sequence in the Grooming Patterns of Six Rodent Species
Authors: Berridge Kent C.
Published: April 2008

The phylogenetic constancy of a set of syntactic patterning rules for grooming was examined in six rodent species: guinea pig, Belding's ground squirrel, gerbil, hamster, rat, mouse. Species were chosen to allow comparisons of separate suborders of Rodentia (Hystricomorpha, Sciuromorpha, Myomorpha) and of separate families within suborders (Cricetidae and Muridae). Each species was examined for possession of the syntactic patterns of chaining, transition reciprocity, sequential stereotypy, and hierarchical clustering. These syntactic patterns were detected and quantified using videoanalysis, graphic notation, and a variety of computer-assisted action coding and analysis techniques. Each syntactic pattern or sequencing rule mentioned above was found to obtain in all six of the species tested. The wide applicability of these rules suggests that they reflect a fundamental feature of neurobehavioral organization, which was established relatively early in rodent evolution. Syntactic organization appears to be a basic property of action production by mammalian brains. The techniques used in this study also allowed a quantitative comparison to be made across species of syntactic pattern strength, form, stereotypy, and timing parameters. This comparison showed that many differences in behavioral patterns among species could be explained by one of two principles. The first explanatory principle was phylogenetic relationship: the behavioral traits of species from within a single family tended to be more similar than were traits of species from separate families, and species from a single suborder tended to be more similar than species from separate suborders. The second principle, which applied especially to temporal parameters, was programmed allometric control by physical size. The timing of patterns (for example, the cycle duration of certain highly stereotyped forepaw strokes performed on the face) was related to the average size of the species by an allometric power function. The nature of these syntactic patterns and of the rules that generate them, the nature of their neural substrates, and the origin of parameters differences between species, is discussed.
An Investigation of Sibling Recognition in a Solitary Sciurid, Townsend's Chipmunk, Tamias Townsendii
Authors: Fuller Claire A. , Blaustein Andrew R.
Published: April 2008

We tested juvenile Townsend's chipmunks (Tamias townsendii) to determine whether 1) they could distinguish kin from non-kin and 2) to assess if this ability was based on familiarity or on genetic relatedness. Seventy-three pups between the ages of 55-62 days were observed in 68 pairwise tests. The frequencies (number/trial) and durations (length in seconds) of 8 behaviors as well as the mean distance between pups were recorded in 10 min. trials. Analyses indicated that frequencies of behaviors varied depending on relatedness (related/unrelated) and familiarity (familiar/unfamiliar) but durations of behaviors did not. Pups discriminated between familiar and unfamiliar animals in the frequency of contacts, and the occurrence of attacks and chases. Pups discriminated between animals on the basis of relatedness in the occurrence of chasing. Both relatedness and familiarity played a role in the frequency of sniffing and grooming and in the mean distance between pups, as shown by the significant interaction between familiarity and relatedness in 2-way ANOVAs. The sex composition of pairs (male-male, male-female or female-female) influenced the mean distance between pups. We can only speculate on the functions of kin recognition in Townsend's chipmunk. It may enable animals to selectively direct nepotistic behavior toward kin or facilitate optimal outbreeding.
Litter Gender Composition, Food Availability, and Maternal Defence of the Young in House Mice (Mus Domesticus)
Authors: Maestripieri Dario
Published: April 2008

Litter gender composition (LGC) of 33 litters of outbred Swiss albino mice was manipulated at birth to obtain 100%-male litters (MM), 50%-male litters (MF) and 100%-female litters (FF). Litter size was 10 in all cases. Litter defence by their respective dams (5-min exposure to an unfamiliar adult male) was scored on postpartum day 7. The influence of litter gender composition on the female's litter defence was tested, with identical procedure, under conditions of restricted feeding. In this case, dams were fed from postpartum days 1-7 with 80% of their normal daily requirement. Under both ad lib. and restricted feeding body weight of mothers and their litters was assessed daily. Under ad lib. feeding, dams rearing MM litters showed higher scores of Total Attacking Time than both MF and FF dams and higher frequency of Attacks and Tail Rattling episodes than MF dams. Food-restricted females showed a sharp decline in body weight and their litters a slower gain in weight than control animals. LGC did not affect mother and litter weight changes in both conditions but MM females tended to cannibalize more pups on days 6-7 than MF and FF females. Food-restricted MM and MF dams showed, respectively, lower Total Attacking Time and higher number of Attacks and Tail Rattling episodes than their own Control groups. These results show that, under ad lib. feeding, LGC affects significantly female mouse litter defence. Some possible underlying mechanisms are discussed. These results support only partly the TRIVERS-WILLARD'S hypothesis (1973) about sex-biased investment in the offspring since, even though mouse dams under ad lib. feeding defended more vigorously all-male litters, as predicted by the model, among food-restricted animals no clear shift toward a prevalent defence of female-skewed litters appeared.
Social Inertia and Hormonal Control of Aggression and Dominance in White-Throated Sparrows
Authors: Archawaranon Manee , Dove Lorna , HAVEN WILEY R.
Published: April 2008

To investigate the effects of familiarity with opponents on the activation of aggression and dominance by testosterone (T) in white-throated sparrows Zonotrichia albicollis, we studied birds in groups of five or six in outdoor aviaries and in a free-living population. Experiments were conducted between January and April, when plasma levels of endogenous gonadal hormones were low. Previously published experiments (ARCHAWARANON & WILEY, 1988) showed that when subjects were given subcutaneous implants of T, held individually in cages for one week, and then grouped with unfamiliar opponents, they established dominance over controls with empty implants. In contracts, the present study showed that low-ranking birds given subcutaneous implants of T and returned to their original groups and aviaries did not change in dominance rank nor in aggression scores over a period of two weeks. When these birds were regrouped with unfamiliar opponents in new aviaries, their dominance ranks and aggression scores increased. This rise in dominance rankings and aggression scores did not result from any effects of regrouping in the absence of hormonal treatments. The sexes did not differ in their responses to these treatments. In the field, T implants markedly increased some individuals' frequencies of aggression but had little or no effect on dominance relationships. The absence of behavioral changes in stable groupings after hormonal treatment, called social inertia, indicates that birds recognize the relative dominance of previous opponents, at least when encountered in familiar locations. Results from the field experiment thus suggest that white-throated sparrows can recognize at least 20 opponents. Hormonal state has more influence on dominance relationships of strangers than on those of opponents familiar with each other in familiar locations.
Competition To Carry Infants in Captive Families of Cotton-Top Tamarins (Saguinus Oedipus)
Authors: Price Eluned C.
Published: April 2008

The Callitrichidae (marmosets and tamarins) typically produce twins, and have communal rearing systems in which all group members help care for the infants. It has been hypothesised that helpers benefit in some way from assisting in infant care. If so, then competition to carry infants would be predicted. This was tested in a study of 14 litters of captive cotton-top tamarins (Saguinus oedipus). All occurrences of infant transfers (movements of infants from one caretaker to another) were recorded from birth to 12 weeks. Individuals in larger groups were less likely to reject infants, more likely to actively take infants, more likely to resist attempts by others to take, and more likely to intervene in transfers, suggesting increased competition to carry in large groups. Singletons were rejected less than twin infants, again suggesting the existence of competition amongst caretakers. Mothers rejected infants more frequently than fathers; young tamarins rejected infants more than older tamarins. There was evidence that carrying by juvenile siblings and by adult daughters was limited by other group members. There was evidence that adult sons and sub-adult sons and daughters competed most strongly, and were more likely to attempt to limit carrying by other group members. These results were interpreted in the light of hypotheses suggesting that the benefits to be gained from helping may differ amongst age-sex classes.
Side-Directed Behaviour and Recruitment of Support in Captive Chimpanzees
Authors: Hemelrijk Charlotte K. , Klomberg Theo J.M. , Nooitgedagt Janneke H. , Van Hooff Jan A.R.A.M.
Published: April 2008

We studied the relation between support in conflicts and side-directed behaviour (i.e. non-agonistic behaviour displayed by one of the combatants to an outsider) in two captive colonies of chimpanzees. Side-directed behaviour was not a precondition to acquire help in fights, since most support was obtained without preceding side-directed behaviour. Besides, side-directed behaviour was rarely followed by the receipt of support and there was no indication that it increased the chance to receive help. Only between females side-directed behaviour was aimed more often at those from whom support was also received more frequently. This suggests that although females were seldom successful to enlist support from one another, this might still have been the aim of their behaviour. Side-directed behaviour was not performed at random: per conflict it was shown more often by females than males; both sexes performed it especially when receiving a conflict rather than starting it themselves and during conflicts with their own sex; both sexes directed it more often to males than females. Further, more side-directed behaviour was directed to partners the higher the rank of the partner. This means that side-directed behaviour brings a threatened individual in the proximity of a high ranking individual, which may function as a protective zone and thus thwart the aggression of the opponent. Although in periods with an unclear alpha-male position males reciprocated support, there was no evidence that this reciprocation was mediated by side-directed behaviour. In these periods males may benefit directly from attacking common rivals. If this is true, both helping and reciprocation may be unintentional.
Feeding Habits and Predatory Behaviour in the Marbled Polecat (Vormela Peregusna Syriaca): I. Killing Methods in Relation To Prey Size and Prey Behaviour
Authors: Ben-David Merav , Pellis Sergio M. , Pellis Vivien C.
Published: April 2008

The marbled polecat (Vormela peregusna syriaca), a small musteline, is represented in the fauna of Israel. Predatory behaviour of eleven marbled polecats, caught in the field, and held in captivity for a reproductive biology study, was observed during their routine feedings over the course of two years. Sequences of prey capture and killing were recorded on film or videotape. Killed prey were also retrieved for autopsy. Prey offered included Gallus gallus domesticus, Mus musculus, Acomys cahirinus, Microtus guentheri, Meriones tristrami, Cavia porcellus and Rattus norvegicus. All prey items were obtained as surplus from medical laboratories. In addition to using the typical musteline killing method of biting the nape of the neck, marbled polecats used a variety of killing methods suited to a range of prey types. Two variables determined the killing method used. 1) Size of prey: Small prey were killed by bites to the thorax, whereas large prey were bitten on the head or neck. 2) Prey defense behaviour: Fleeing prey were bitten dorsally, whereas defending prey were bitten ventrally, typically on the throat. This non-stereotypical predatory behaviour appears to correlate with the opportunistic feeding habits of marbled polecats in the wild. Evolutionary and ecological aspects of this relationship are discussed.
Allomaternal Care By Female Wedge-Capped Capuchin Monkeys: Effects of Age, Rank and Relatedness
Authors: O'Brien Timothy G. , Robinson John G.
Published: April 2008

We examined patterns of infant care and the relative importance of female age, rank and relatedness to allomaternal care for a wild population of wedge-capped capuchin monkeys, Cebus olivaceus in Venezuela. Mothers interacted primarily with their own infants throughout the study. Infant age affected the timing and type of allomaternal interaction; investigation occurred primarily in the first 3 months of life, carrying was dominant during the second 3 months, and association occurred primarily in the third 3 months. The onset and level of allomaternal care assured a high level of infant care as maternal care was declining, suggesting that allomaternal care is an important component of infant survival. The relative importance of female age, rank and relatedness varied for different behaviour. Relatedness was the most consistently important effect. Sibling females participated in allomaternal care almost 4 times more often than other females and were especially active in carrying and associating with infants. Female rank was an important effect when the coefficient of relatedness was less than 0.5: high-ranking females participated in allomaternal care more than low-ranking females. Old juveniles and nulliparous adults interacted with infants more than young juveniles and parous adults, but the effect of female age was relatively unimportant. Allomaternal nursing may represent a form of reciprocal altruism. Allomaternal nursing supplemented maternal nursing and was unrelated to kinship or rank of female.
Temporal Relationships, Transitions and Structure of the Behavioural Repertoire in Male Apennine Chamois During the Rut
Authors: Lovari S. , Locati M.
Published: April 2008

The reproductive behaviour of adult male Apennine chamois was studied during 4 rutting seasons in the Abruzzo National Park, Central Italy. The analysis of temporal relationships between behaviour patterns in male-male and male-female repertoires has allowed to group together the patterns functionally associated. Courtship activities were much more predictable and fixed than behaviours in male-male interactions. Qualitative and quantitative variations of the main behaviour patterns have been evaluated throughout the rut. November 8-12 marked the start of the intense phase of the rut. Two of the 3 species-specific courtship behaviours appeared in the peak of the rut (November 23-27). Older males grouped and successfully defended larger harems, containing a greater number of prime females. Males herded females mainly by the Head Down threat, in both the still and moving postures. The aggressive connotation of the Snort, an usually assumed "alarm" call, has been here discussed in the harem formation context. The courtship sequence has been described. The function of female reactive urination was evaluated in this context. A harem holder did not only have to prevent females from leaving, but he had also to deal with male competitors. Usually long agonistic interactions occurred before a Rush or a Chase ended up the contest between 2 males. The Neck Up has been presented here as an effective posture to display the "Attention Guiding Adaptations" present in the body morphology of adult male chamois. Direct correlations were found between the age (i.e. the dominance) of an intruder and the distance at which it was pursued away by the harem holder, as well as the Marking/Horning activity of the latter. The frequency of utterance of the Rut Call built up 60% of all behaviour patterns recorded (N = 8059). It was also used often (36.3 % ; N = 102) to initiate a contest as a vocal dominance display. Harem holders showed a positive correlation of call frequency to the harem females with the rut progression. The last 2 aspects suggest a strong similarity of function to what found for the red deer in assessing the contenders' ranks and in enhancing the oestrus of females. The comparison of male rutting behaviour in Apennine chamois with that reported for other Rupicapra taxa indicated a close affinity with the Pyrenees subspecies and detectable differences with the northeastern chamois.
Olfactory Search Images in Striped Skunks
Authors: Nams Vilis O.
Published: April 2008

Striped skunks (Mephitis mephitis) which had been raised in captivity can increase their reaction distance to the smell of a given food. This reaction distance decreases after they find other types of foods, using either sound or smell. This decrease could be a result of skunks increasing preference for specific food, or shifting attention onto the smell of specific food. However, other experiments showed that skunks do not change prey preference. Therefore the decrease in reaction distance is likely due to skunks shifting attention to the smell of specific food. I suggest that this is the olfactory analogue to visual search images-i.e. olfactory search images.
Animal Grouping for Protection From Parasites: Selfish Herd and Encounter-Dilution Effects
Authors: Mooring Michael S. , Hart Benjamin L.
Published: April 2008

Grouping has been widely accepted as a mechanism for protection from predation. Just as has been apparent with predation, there is now ample evidence that parasites (biting flies, warble flies and parasitoids) can impact an animal's individual fitness. Some aspects of grouping, namely an encounter-dilution effect and the selfish herd effect, appear to apply as much to protection of animals from flying parasites as protection from predators. The encounter-dilution effect provides protection when the probability of detection of a group does not increase in proportion to an increase in group size (the encounter effect), provided that the parasites do not offset the encounter effect by attacking more members of the group (the dilution effect). The selfish herd effect provides protection from flying parasites to animals that are in the center of a group or more closely placed to other animals. Most of the quantitative evidence for the protection from flying parasites from grouping comes from studies on ungulates. Further investigation of these effects among a variety of taxa is needed for a full appreciation of the role of parasites in animal grouping and sociality.
Mother-Offspring Separation and Acoustic Stereotypy: a Comparison of Call Morphology in Two Species of Pinnipeds
Authors: Insley Stephen J.
Published: April 2008

I have compared structural variation of the primary vocalizations used between mother-offspring pairs in two species of pinnipeds that differ fundamentally in their breeding behaviour: northern elephant seal (Mirounga angustirostris) mothers and offspring normally are together throughout the nursing period; northern fur seal (Callorhinus ursinus) females regularly separate from their offspring while nursing. Two predictions were tested: (1) these vocalizations should be individually-distinct (stereotyped) in females and pups of both species if they serve to function for recognition, and (2) because individuality should be more pronounced in a species where separations and reunions are common, the vocalizations used between northern fur seal mother-offspring pairs should be more individually-stereotyped than those of the northern elephant seal. Principal components analyses revealed structural differences between the calls of females and pups in both species. Analysis of variance showed the calls of individual seals to be acoustically distinct in all cases. The calls used between mother-offspring pairs of northern fur seals were more stereotyped than those of northern elephant seals. These calls had less within-individual variation, greater among-individual variation and were more often correctly predicted in discriminant analyses. The results indicate that selective pressure to develop vocal recognition exists in both species but is greater in the northern fur seal.