bluuebunny/crossref_metadata_2025_split huggingface dataset:
Food Scrounging and Diffusion of Foraging Skills in Pigeons, Columba livia: The Importance of Tutor and Observer Rewards
Authors: Giraldeau Luc‐Alain , Templeton Jennifer J. 
Published: May 2010

AbstractNaive feral pigeons (Columba livia) adopt novel foraging skills after watching tutors demonstrating them. Despite this ability, novel foraging skills do not always spread within pigeon flocks. Two factors are important in determining whether skills will spread or not. 1) Tutor reward: naive observers fail to acquire a novel skill if the tutor is not rewarded for its demonstration. 2) Scrounging: observers also fail to acquire the skill when they obtain rewards from the tutor's demonstrations (i.e. when they scrounge). We examine jointly the relative importance of tutor reward and of scrounging in promoting the diffusion of skills. Moreover, we investigate how magnitude of scrounger reward could affect the diffusion of skills. In Experiment 1 we found that scrounging had a stronger effect than tutor reward, but that the performance of observers was inhibited most strongly when tutors obtained no reward and observers scrounged. In Experiment 2 we found that the magnitude of scrounger reward had no effect on observers' acquisition of skills when tutors were rewarded. These results, taken with those of earlier work, suggest that variables such as tutor reward and scrounging, as well as task complexity and density of tutors in groups, are important factors affecting skill diffusion within groups.
The Consequences for Communication of Call Overlap in the Tungara Frog, a Neotropical Anuran with a Frequency‐modulated Call
Authors: Schwartz Joshua J. , Rand A. Stanley 
Published: May 2010

AbstractWe presented male tungara frogs,Physalaemus pustulosus, with call‐triggered computer‐synthesized whines that either did or did not overlap the frogs' own frequency‐modulated whines in time. When the stimulus was nonoverlapping, males added a high proportion of chuck notes to their calls. When the stimulus was overlapping, males responded with either no or only small increases in chucking. This suggests they have difficulty detecting whines while vocalizing. When female tungara frogs were given a choice between alternating whines and out‐of‐phase overlapping whines they did not discriminate. The result with males was similar to that previously obtained with species of frogs that have amplitude‐modulated advertisement calls (Schwartz1987a), the result with females was different. We discuss our findings in relation to peripheral processing of spectral and temporal information in the anuran auditory system.
Of Ducklings and Turing Machines: Interactive Playbacks Enhance Subsequent Responsiveness to Conspecific Calls
Authors: Evans Christopher S. 
Published: May 2010

AbstractDistress calls of mallard ducklings consist of a highly stereotyped series of notes. When two ducklings are simultaneously separated from the brood, they characteristically call in alternation. Each bird inhibits its calls while the other is vocalizing, thus preventing masking and facilitating localization by the hen. I examined whether exposure of ducklings to calls presented in a naturalistic alternating pattern affected subsequent responsiveness to them. Individual ducklings were exposed to either 40 s or 80 s of computer‐controlled distress call playbacks, using an algorithm that mimicked the behavior of another duckling. Calls were presented only when the subject was silent and ended as soon as it began to vocalize. Each of these ducklings was paired with a ‘yoked’ control. Birds in these control groups experienced exactly the same pattern of playbacks as the ‘interactive’ birds, but the stimuli had no consistent relationship to their own vocal behavior. When the same calls were played back 24 h later, in a fixed pattern that was independent of the ducklings' behavior, birds that had received 80 s of prior interactive exposure were significantly more responsive than both their yoked controls and birds receiving only 40 s of such playbacks. This result suggests that interactive vocal experience, characteristic of natural communication, affects the subsequent perceptual sensitivity of ducklings.
A Failure to Demonstrate Host Imprinting in the Cuckoo (Cuculus canorus) and Alternative Hypotheses for the Maintenance of Egg Mimicry
Authors: de L. Brooke M. , Davies N. B. 
Published: May 2010

AbstractThe cuckoo Cuculus canorus is divided into various gentes, each laying a distinctive egg and favouring a different species as host. It has long been assumed that the gentes remain distinct because female cuckoos lay the same egg‐type as their mother and prefer the same host, developing this preference by imprinting on their foster parents. We tested whether imprinting occurred by laboratory experiments with 7 cuckoos originating from reed warbler Acrocephalus scirpaceus nests. Two were transferred soon after hatching to robin Erithacus rubecula nests and were raised by robins, while the other five were raised by reed warblers. When about 12 d old, the nestling cuckoos and their foster parents were transferred from the wild to aviaries, where the fosterers continued to raise the cuckoos to independence. The fosterers were then released and the cuckoos retained and presented, at one and two years of age, with a behavioural choice between robins and reed warblers. None of the cuckoos (five females and two males) displayed a consistent preference for the host that reared them even, in the case of females, after oestradiol implantation. We discuss the inadequacies of our experiment and present data on cuckoo egg types to test whether natal philopatry might be sufficient to maintain the gentes. We suggest that mitochondrial DNA studies, now underway, will help to resolve the issue.
The Social System of a Communal Breeder, the Bay‐winged Cowbird Molothrus badius
Authors: Fraga Roswndo M. 
Published: May 2010

AbstractMolothrus badius (bay‐winged cowbird), an icterine blackbird with cooperative breeding, shares behavioural and ecological characteristics with other communal nesters: it is sedentary, has a high annual survival rate (76.2%) and a strong nest‐site tenacity (mean breeding dispersal of 41.9 and 89.4 m for males and females). Behavioural data, including collective agonistic displays, suggest group territoriality.Before egg hatching most breeders occurred as single pairs showing territorial behaviour (82% of nests), and nesting was usually solitary (distances to nearest nests of 25–103 m). Most breeders were apparently monogamous, with a 2.5% incidence of extrapair copulations in the territory during clutch formation. During the nestling stage one to four helpers occurred at 95% of M. badius nests. Most helpers were 1–2 years old, but older breeding adults (mostly males) that failed to rear their own offspring helped at the end of the season. The number of helpers increased (up to 4) with nestling age. Helpers were also recruited during the postfledging period, and group size reached up to 10 adults at this stage.Helpers mobbed predators and brood parasites, and provided 35% of the nestling food. Provisioning rate was positively and significantly correlated with number of helpers, although age of nestlings was the best predictor of overall food delivery rate. The helping system was almost obligate and productivity comparisons between nests with/without helpers are not possible. Data suggest that helpers increased the breeding success per nest. The correlation between the provisioning rates of parents and helpers was negative but non‐significant.In 18% of nests 3 to 4 individuals were present before the nestling period, including cases of apparently polyandrous trios and one case of joint nesting by two pairs. Within Brown's (1987) categories of social organization M. badius is mainly group territorial with plural nesting. Habitat requirements of M. badius are wide and nest sites do not appear to limit breeding. Kinship plays a role in the social system, as 9 of 12 helpers marked as nestlings helped their parents.
Operational Sex Ratio and Individual Mating Frequencies in Two Bushcricket Species (Orthoptera, Tettigonioidea, Poecilimon)
Authors: Heller Klaus‐Gerhard , von Helversen Dagmar 
Published: May 2010

AbstractDuring mating the male bushericket transfers a large spermatophore which is consumed by the female after copulation. Such a ‘nuptial gift' is likely to have strong effects on the mating frequency of both males and females and thus on the operational sex ratio (OSR): For the male a longer time period will be required in which he is prevented from further matings. For the female consumption may be advantageous increasing interest in matings.To quantify these effects field studies were carried out on two species of the genus Poecilimon. Both species differed widely in the mean number of matings observed per day (19% of all females in P. veluchianus compaied to 42% in P. affinis; Fig. 2) and thus in the distribution of female mating intervals (P. veluchianus 2 days, P. affinis 1 day (modes); Fig. 3). Separate experiments on the minimum male mating interval and the spermatophore weight also revealed distinct differences: the mean spermatophore weight was 26% of the male body weight in P. veluchianus and 15% in P. affinis (Fig. 6). Accordingly the refractory period was longer in P. veluchianus; 3 days after a previous mating nearh all males were ready to remate, compared to 2 days in P. affinis (Fig. 5). These differences, however, compensated one another in that the amount of spermatophylax material transferred per day was very similar in both species in relation to female body weight.Using data on female mating frequency per day and male remating ability, an upper estimate for the OSR was calculated. A lower limit for the OSR was given taking into account the most frequent female mating interval (big. 7). In both species the OSR remained relatively constant for large parts of the season. The medians (upper/lower estimate for the ratio males to females ready to mate: 2.95/1.19 in P. veluchianus; 2.22 0.88 in P. affinis) were very low, comparable to that in explosive breeding frog species. Thus in the bushcricket mating system, females may be able to demand large male mating efforts so that the operational sex ratio can come close to unity.
Male‐female Parental Roles in Sarotherodon galilaeus (Pisces: Cichlidae)
Authors: Schwanck Erkki , Rana Krishen 
Published: May 2010

AbstractSarotherodon galilaeus is a predominantly biparental, sexually monomorphic mouthbrooder. 15 spawnings of pairs in the weight range 150–450 g were observed in aquaria. Only clutches of females larger than 320 g were reared jointly; with those of smaller females, the first fish to pick up eggs brooded alone, while the comparatively few eggs left for the second fish were invariably eaten. The latency after which eggs were picked up increased with the duration of spawning and indirectly with fish size. This increase was larger in males than in females, so large males started to collect eggs later than their mates. In small pairs (female weight < 200 g), by contrast, the male would pick up eggs first and carry them alone. This is the case in a smaller congeneric species, S. melanotheron, indicating that the apportioning of broodcare is based on a unitary, size‐dependent mechanism among Sarotherodon. Yet picking‐up order was not entirely determined by these equations. Some fish did not show any reaction towards the eggs and occasionally males became care‐givers despite expected longer latency, seemingly because of aggressive dominance.
Aggressive Thresholds of Male Pacific Treefrogs for Advertisement Calls Vary with Amplitude of Neighbors' Calls
Authors: Rose Gary J. , Brenowitz Eliot A. 
Published: May 2010

AbstractIn breeding choruses, male Pacific treefrogs (H. regilla) produce advertisement and encounter calls. The role of each call type in establishing intermale spacing patterns was investigated by playing back, at various amplitudes, recordings of these vocalizations to resident males. The aggressive threshold of a male for each call type was defined as the lowest amplitude of playback that elicited encounter calls. Pacific treefrogs consistently had lower aggressive thresholds to playbacks of encounter calls than to playbacks of advertisement calls. Aggressive thresholds to playbacks of advertisement calls were positively correlated with the maximum amplitude of the advertisement calls of neighboring males, as measured at the position of the focal male.
Aborted Polygyny in the Lesser Kestrel Falco naumanni (Aves, Falconidae)
Authors: Hiraldo Fernando , Negro Juan José , Donázar José Antonio 
Published: May 2010

AbstractWe observed three polygynous trios (one male and two females) in a colony of lesser kestrels in southern Spain. All these trios broke up before egg‐laying because the secondary female deserted and paired with another male. The time spent by the bigamous males with the female at the colony, the copulation rates, and the mate‐feedings, were always lower for the secondary females. Primary females received levels of investment similar to that obtained by females paired with monogamous males. Aggressions between the two females paired with the same male were frequent. Polygyny in the lesser kestrel might be favoured by a female biased sex‐ratio, and maintained because bigamous males and secondary females can get some benefits, independently of the final success of the breeding attempt.
Factors Influencing Leadership: A Study of Goose Families (Anser indicus)1)
Authors: Lamprecht Jürg 
Published: May 2010

AbstractStarting from the proposition that leadership in animal groups is closely related to proximity maintenance between members, the relative contributions to mutual proximity (approach/leaving index) of parents and offspring were determined for 29 semi‐captive bar‐headed goose families (Anser indicus) in the context of undisturbed feeding. Up to 6 d of age goslings contributed more, when older than 10 d less than their parents to proximity. The percentage of following by parents was negatively related to goose density, and positively to the frequency of defence when offspring were very young, and to brood size when offspring were older. The results are compared with opposite findings in monkeys and explained in terms of likely benefits of leaving and following. Two general characteristics of group leaders (competence or need of support) are suggested.
Behavioural Variability and Development of Cataglyphis cursor Ant Workers (Hymenoptera, Formicidae)1)
Authors: Retana Javier , Cerda Xim 
Published: May 2010

AbstractVariability and development of behaviour among Cataglyphis cursor ant workers was analyzed, after identifying each member of the studied nests by individual marking. Behavioural differences between workers of the same nest were considerable, even when they were assigned to the same behavioural class defined with multifactorial analysis. Workers' behaviour also changed considerably over short‐time intervals, for example from one day to another.Behavioural development was very variable. Only ⅓ of the workers followed the classical age polyethism, while the remainder showed stable behaviour or irregular variations from the expected scheme.
Maternal Behaviour and Nest Recognition in the Subsocial Earwig Labidura riparia Pallas (Dermaptera: Labiduridae)
Authors: Radl Ruth C. , Linsenmair K. Eduard 
Published: May 2010

AbstractMaternal behaviour in Labidura riparia includes care for eggs and for newly hatched larvae. Females provide their young with food and defend them (e.g. against conspecifics). Foraging females have to leave their nest and must find their way back to the brood chamber. Several active brood chambers can be situated in close vicinity in the field. This could cause identification problems. We demonstrate that females are unable to distinguish own from alien offspring. They discriminate, however, their own brood chambers from alien nests by individual‐specific recognition pheromones (discriminators) produced by the female and transferred to the nest substratum. Thus brood care is reliably restricted to the own progeny. The larvae leave the nest 2–5 d after hatching. After the first excursion the larvae do not return to their mother's nest.
Development of Social Structure in a Captive Colony of the Common Vampire Bat, Desmodus rotundus
Authors: Park Shi‐Ryong 
Published: May 2010

AbstractThe development of social structures of the vampire bat (Desmodus rotundus) was studied in small groups in a captive colony over a period of 30 months. The membership of individuals in the main group and the development of group formation were evaluated by the coherence index. The main group of the vampire colony consisted of several adult females, their infants and one harem male. All members of the main group showed relatively high coherence indices, while the coherence index of adult males, except the harem male, was 0. The females and young in the main group formed a very stable group in comparison to the adult males. The young males left the main group at 20–27 months of age and formed temporary bachelor groups. The harem males changed during the study in the period from 1 to 20 months. They exhibited territorial behaviour and made vigorous attempts to approach the main group within the bounds of their roosting areas, whilst also keeping out intruders.
Black Coots (Fulica atra; Aves, Rallidae) Supplanting Conspecifics from Foraging Sites
Authors: Amat Juan A. , Obeso J. Ramón 
Published: May 2010

AbstractWhen individuals forage in groups they may acquire information on the quality of feeding sites from observations of the activities of other individuals. During the non‐breeding season, black coots (Fulica atra) directed attacks at conspecifics with the main purpose of supplanting them from foraging sites. By supplanting, coots did not increase the amount of food ingested relative to birds feeding undisturbed, but instead reduced the costs associated with obtaining food by spending less time foraging by the more costly method. The rate of food intake of supplanted coots was lower than that of undisturbed birds, probably not only because following the displacement they moved away, but also because immediately after moving the time spent feeding on plants brought to the surface after each dive was shorter, although they dived with the same frequency as undisturbed coots did. This indicates that supplanted coots were displaced to sites of lower quality. Probably, the extent to which supplanting was performed was related to a decline in food quality arising from dry conditions.
Territorial Significance of Scent Marking during the Non‐mating Season in the Aardwolf Proteles cristatus (Carnivora: Protelidae)
Authors: Richardson Philip R. K. 
Published: May 2010

AbstractPatterns of scent‐marking by male and female aardwolves during the non‐mating season in the northern Cape Province are described. The distribution of scent marks conforms to predictions for marks being used as territorial advertisements. Scent marks were concentrated around territory borders and were deposited at increasingly higher densities in smaller territories. The data are used to re‐examine existing hypotheses as to how scent marks function in territory maintenance. Scent marks provide an olfactory association between the resident and the defended area, but I suggest that the message provided by this association may depend heavily on territory size, the frequency of territorial encounters and the defensive behaviour of the resident. The greater the territory size and hence the difficulty in monitoring intrusions, the greater the threat transmitted by scent marks needs to be. In most territorial carnivores, scent marks may be interpreted by intruders as a threat of immediate physical attack if encountered by the resident. Thus scent marks help to maintain, but cannot ensure, territorial integrity in the temporary absence of the resident.
Route‐based Visual Information has Limited Effect on the Homing Performance of Red Squirrels, Tamiasciurus hudsonicus
Authors: Bovet Jacques 
Published: May 2010

AbstractThe role of route‐based visual information in the homing behavior of red squirrels (Tamiasciurus hudsonicus) was assessed in an experiment contrasting the homing performance of 8 squirrels that could see the landscape during displacement and that of 8 squirrels that could not. Availability of route‐based visual information improves the accuracy of homeward orientation but is of no use for the animals to assess distance to home. These findings are congruent with the “critical‐distance model” (Bovet 1984, 1987) which implies that choice of direction and estimation of distance are independent processes in the homing performance of untrained animals.
Sex Differences in Giraffe Feeding Ecology: Energetic and Social Constraints
Authors: Young Truman P. , Isbell Lynne A. 
Published: May 2010

AbstractSex ratios of giraffe groups differ in different habitats, with open vegetation having female‐biased groups, and tall, thick vegetation having male‐biased groups. On a ranch in south‐central Kenya, we quantified habitat differences of male and female giraffe groups and showed that the preference for open habitats by female groups was limited to groups with young. We suggest that this difference is due to the avoidance of predators of young giraffes. We also showed that rates of giraffe feeding peaked at intermediate feeding heights equal to approximately 60% of adult giraffe height. In the dense habitats with a variety of tree heights used by male groups and female groups without young, both male and female giraffes fed most at heights where they could feed fastest. However, in the open habitats used by female groups with young, females fed mostly at heights below optimum because these habitats are dominated by short food plants. On the other hand, the dominant males accompanying these female groups fed at heights above optimum on rare tall trees, possibly to increase intrasexual vigilance. Apparently, both male and female giraffes sometimes forfeit feeding efficiency tor short‐term reproductive gains.
Colony Energy Requirements Affect Response to Predation Risk in Foraging Bumble Bees
Authors: Cartar Ralph V. 
Published: May 2010

AbstractForaging animals must often be sensitive to the dual risks of predation and energy shortfall, and should devalue risk of predation as risk of starvation increases. This study examines whether the probability of colony‐level energy shortfall influences the predation risks taken by individual foraging bumble bees (Bombus occidentalis) in confined colonies as they collected sugar water from artificial flowers. Before each trial, colony energy stores were manipulated by enhancing or removing the contents of the colony's honey pots. Feeding bees were significantly more likely to flee from an artificial predator model (a black styrofoam ball moved overhead) when their colony's energy stores were enhanced, relative to when their colony's energy stores were depleted. Despite their defensive stings and aposematic coloration, bumble bees are more likely to accept “risky” foraging situations when the energy needs of their colony are increased.
Why is the Eye‐like Spot of the Oyanirami Fish Coreoperca kawamebari Located near the Real Eye?
Authors: Kohda Yasutoshi , Watanabe Munetaka 
Published: May 2010

AbstractIn agonistic encounters an oyanirami (Coreoperca kawamebari) displays laterally to a rival. The lateral pattern is thought to have a threatening effect, eliciting aggressive reactions. A conspicuous eye‐like spot near the real eye is a main component of the pattern and is almost a key stimulus releasing aggressive actions of rivals; it has been shown, however, that the position of the spot has no connection with this effect. In the present study, video‐taped bites on two dummies were examined, one with the normal aggressive pattern and one with an artificial posterior‐spotted pattern. The natural eye‐like spots deflected attacks from the real eyes, but the artificial spots further from the real eyes did not. Only the nearby eye‐like spots can preserve the real eyes from rival attacks.