Showing papers in "Animal Behaviour in 1996"

TL;DR: In this paper, the authors pointed out that the functional explanation of the group size eVect remains unclear, and suggested that the individual risk hypothesis, with group vigilance as one element, provides a more general framework for understanding variation in vigilance behaviour with group size and with other factors.

TL;DR: F Females' responses to playbacks suggested the additional possibility for categorical recognition of matrilineal kinship, or its correlates, and results indicate an ability for vocal recognition of both individuals and kin.

TL;DR: Experimental results suggest that female mate choice in the guppy is potentially costly in terms of an increased risk of mortality due to predation and that females from different populations are differentially sensitive to this risk when assessing and choosing potential mates.

TL;DR: In this article, the patterns of echolocation sounds produced by killer whales, Orcinus orca,o V British Columbia and Alaska are described, and two sympatric populations with divergent food habits diVered markedly in sonar sound production.

TL;DR: Male Drosophila melanogaster exposed to virgin females that were experimentally prevented from mating had a higher death rate than males exposed to an equal number of inseminated females and mounting attempts may be an indicator of an altered metabolic rate or hormonal status that renders the males more susceptible to death.

TL;DR: Pike-naive damselflies may initially respond to chemical stimuli from pike based on stimuli of conspecifics or familiar hetero- specifics in the pike's diet, and damselflie can learn to recognize chemical stimuli of pike irrespective of the pikes' recent feeding regime based on the initial association with damselfly or minnows in thePike's food.

TL;DR: It was found that randomization tests were more powerful than Kruskal–Wallis, and could thus detect smaller effect sizes present in the data, and thus it is recommended that at least 5000 replications be used forrandomization tests on behavioural data.

TL;DR: The shorter travel distances and feeding bouts experienced by consorting males may represent important constraints on male foraging activity, and probably result in decreased energy intake during mate guarding.

TL;DR: Individuals that live in groups may have the opportunity to learn to recognize unfamiliar predators by observing the fright responses of experienced individuals in the group by being alerted to the immediate presence of unfamiliar predators and learning to recognizing unfamiliar predators as a potential threat.

TL;DR: Results show that western toad tadpoles can distinguish between predatory and non-predatory heterospecifics with which they co-occur, and that predator recognition by toad Tadpoles is primarily based on chemical cues.

TL;DR: The relationship between sample size, biological significance and statistical power is discussed in this article, where the authors use an example from Animal Behaviour to illustrate the importance of power analysis and the consequences of ignoring power.

TL;DR: These experiments demonstrated that individual repertoires and duet precision do not change following a change in mates, refuting the pair bond maintenance hypothesis, and unpaired birds do not lose their territories, failing to support the hypothesis that duets are necessary for territory defence.

TL;DR: It was predicted that species in which running ability declines greatly as diameter decreases should switch to escape by jumping more often than species that experience less of a decline in running ability, but this prediction was not confirmed.

TL;DR: It is shown experimentally that vocal development in songbirds can be affected by physical limits on how birds are able to sing, and how the development and evolution of trill structure can be limited by motor constraints on vocal production.

TL;DR: This article found that song sparrows reply to the songs of particular neighbours with particular songs from their repertoire: they select a song type they share with that neighbour (repertoire matching) and in a field experiment, neighbour song was played to the subject from just inside the neighbour's territory.

TL;DR: In yellow-headed blackbirds, even when nestmates have unequal competitive abilities, begging can carry information about nestling long-term need for food, and when hunger level was controlled, males and chick in poor condition begged more than females and chicks in good condition.

TL;DR: It is suggested that the perishability of seeds exerts a greater influence than handling time on the grey squirrel's decision to cache acorns, and predicts the predictions for caching behaviour that follow from these two hypotheses.

TL;DR: Phylogenetic analyses suggest that tufts are apomorphic, and that S. rovneri is more basal within the clade than S. ocreata, which may provide evidence of pre-existing bias and/or sexual selection for a novel trait.

TL;DR: Foraging and roosting behavior of free-ranging common ravens was studied during the winters of 1988-1990 as discussed by the authors, and it was found that raven roosts function as information centers.

TL;DR: The consequences of sex-biased dispersal in wild dogs are consistent with both hypotheses, but the competition for mating opportunities hypothesis is supported only within the context of dispersal behaviour indicative of close inbreeding avoidance.

TL;DR: The results suggest that mouse-eared bats are opportunistic predators that maximize their average rate of food intake by balancing habitat selection.

TL;DR: The present study on wild female Japanese macaques revealed the occurrence of within-group feeding contest competition for their main winter food item, seeds of Zelkova serrata, and showed that the rank-related difference in feeding behaviour increased when available ZelKova patches were small relative to the area of group dispersion.

TL;DR: Odours naturally associated with chemical defence in insects or plants do enhance neophobia, but only when presented in conjunction with prey that has a novel appearance, and confounding factors such as differences in odour intensity cannot at present be excluded.

TL;DR: It is argued that because female fitness is determined, at least in part, by body size relative to competitors, an evolutionarily stable strategy approach is required to calculate optimal clutch size when host ownership contests occur and this provides a candidate explanation for the previously reported discrepancy.

TL;DR: Prolactin levels were significantly correlated with the number of visits to the nest, as well as the amount of food delivered to the young, lending further support to the hypothesis that helping behaviours are mediated by prolactin.

TL;DR: Sexual attractiveness may be a potentially important mechanism by which brood size affects fitness in zebra finches.

TL;DR: Although there is selection for males to discriminate in favour of their own offspring it is argued that they are unable to do so because of conflicts between the male, female and offspring over signalling identity, and because the circumstances associated with extra-pair paternity disrupt the operation of some mechanisms.

TL;DR: This study compared snail habitat use in Michigan lakes that contain a predator, the molluscivorous pumpkinseed sunfish, with snail habitatuse in adjacent lakes lacking pumpkinseeds, to test the existence of chemically mediated predator avoidance behaviours in Physella.

TL;DR: During a 7-year study of lifetime breeding success in an unconfined population of red junglefowl, only a small proportion of the most dominant cocks and hens produced most of the adults of succeeding generations, suggesting ample basis for random differentiation of local populations in this species.

TL;DR: The prediction was tested that piglets with relatively low weight gains, and thus in greatest need of energy or nutrients, would spend more time in close proximity to the sow and therefore assume a higher mortality risk from crushing, and this held both within and between litters.