Effects of group composition on agonistic behavior of captive pigtail macaques,Macaca nemestrina

We surveyed agonistic behaviors of 20 captive groups of pigtail macaques (Macaca nemestrina) housed under identical spatial conditions. Fifteen groups contained one male each; the other five groups contained no adult males. Groups included six to twelve adult females, some of which had infants with them. We found no relationship between social density of groups and incidence of agonistic behavior, but significantly more contact aggression (grab, hit, push, bite) and noncontact aggression (chase, open-mouth “threat,” bark vocalization) occurred among females in groups containing no males than in those containing one male each. Apparently, males played an important role in the inhibition of intragroup conflict. We also found that females in groups containing males exhibited less noncontact aggression if infants were present than if no infants resided in their groups. Thus, competition of females over infants must not have been an important constituent of intragroup conflict under the conditions of this survey.     

Strong temporal consistency in the individual foraging behaviour of Imperial Shags Phalacrocorax atriceps

Individual consistency in foraging behaviour can generate behavioural variability within populations and may, ultimately, lead to species diversification. However, individual‐based long‐term behavioural studies are particularly scarce in seabird species. Between 2008 and 2011, breeding Imperial Shags Phalacrocorax atriceps at the Punta León colony, Argentina, were tracked with GPS devices to evaluate behavioural consistency during their foraging trips. Within a breeding season, individuals were highly consistent in the maximum distances they reached from the shore and the colony, as well as in the time invested in flight and diving across consecutive days during early chick rearing. In addition, each individual had its specific foraging area distinct from the foraging area of other individuals. Comparing between early and late chick rearing in the same season, individuals were consistent, to a lesser degree, in the maximum distance they reached from the colony and the shore, increasing in consistency later on in the season. Within the season, females were more consistent than males in the maximum distance they moved from the colony and the shore, the sexes segregated in their foraging areas and individual females were segregated from one another. Twenty‐eight individuals tracked in different breeding seasons were marginally consistent in their trip durations and maximum distance reached from shore across seasons. Among seasons, foraging locations differed between sexes and among individual females. Individuals from this colony exhibited consistency over time in several aspects of foraging behaviour, which may be due to a combination of individual characteristics such as learning abilities, breeding experience or health, as well as targeted prey type and stability of the environment at this location.     

Limited dispersal by Nazca boobies Sula granti

We documented natal and breeding dispersal at several spatial scales by Galápagos Nazca boobies Sula granti, a wide‐ranging pelagic seabird. We found exceptionally low degrees of both types of dispersal despite these birds’ vagility. Median natal dispersal distances were 26 m and 105 m for males and females, respectively. Median breeding dispersal distances for both sexes were 0 m. No natal or breeding dispersals occurred from our study site at Punta Cevallos, Isla Española to six other colonies in the Galápagos, but we did document four long‐distance natal dispersals from Punta Cevallos to islands near the South American coast. Recaptures and dead recoveries of ringed birds showed long distance non‐breeding movements to the Central American coast and elsewhere in the eastern Pacific, contrasting with the very limited dispersal to breeding sites.     

Infanticide and Maternal Offspring Defence in European Rabbits under Natural Breeding Conditions

Infanticide is an important source of mortality of dependent offspring in several mammal species, whereas female conspecifics are often the perpetrators. This has led to maternal counter‐strategies, such as the defence of the nests. However, cases of infanticide are hard to detect in the field, and studies on maternal offspring defence behaviour under natural breeding conditions are scarce. We conducted such a study on the European rabbit (Oryctolagus cuniculus), which is usually considered to show low maternal care. The study was carried out over 5 yr on a field enclosure population. We (1) studied infanticide rates and the impact of potential determinants: the group density and age structure of the females’ rank hierarchy within the groups; we used the latter as an estimator of social group stability. We (2) studied if mothers defend their breeding burrow against approaching, potentially infanticidal females. Overall, we recorded infanticide in 5% of all litters; infanticide was the cause in 12% of cases of litter mortality. The proportion of infanticide was 7% higher in groups where same‐age females occupied successive rank positions than in groups where the females’ rank hierarchy had a more heterogeneous and linear age structure. We hypothesize that social instability in the former groups was the reason for the increased infanticide risk. Infanticide rates were not correlated with group density and did not differ among mothers with different social ranks. Infanticide occurred exclusively during the first 10 d after parturition. During this time, mothers stayed closer to their breeding burrows than shortly before parturition or during later lactation. Moreover, mothers were more aggressive against other females in proximity to their breeding burrow than in more distant areas. We suggest that the pattern of spacing behaviour and intrasexual aggression of rabbit mothers are an adaptive response to the occurrence of female infanticidal behaviour.     

Influence of gonadal hormones and social housing conditions on agonistic,copulatory, and related socio-sexual behaviour in the Mongolian gerbil (Meriones unguiculatus)

The Mongolian gerbil is colonial, but its social organization within its colonies is not known. Pair formation has been suggested by breeders and has been observed under semi-natural conditions. Family units remain stable under such conditions. In the solitary-living hamster (Cricetus auratus), agonistic behaviour decreases in male-female encounters during female heat. This report concerns the influence of female and male gonadal hormones on agonistic behaviour in gerbils studied in cagemate and non-cagemate encounters. Further, the occurrence of mating, marking, and drumming was studied in the same situations. No effects were found of either the female or the male endocrine condition on the low amount of agonistic behaviour between cagemates. A reduction in the high amount of agonistic responses in encounters between non-cagemates was indicated. It was related to the castrated-male and induced-oestrous female conditions. Copulatory behaviour was not influenced by social maintenance conditions. Marking and drumming were most frequent in females in oestrous and intact males. The occurences in the females were influenced by the individual's endocrine condition, but not by the opponent's. Intact males in encounters with non-cagemates marked more frequently when the females were in anoestrous. Drumming in the intact males increased in tests with oestrous versus anoestrous females but occurred more frequently in encounters with non-cagemates than in those with cagemates. The behaviour of castrated males was not influenced by the endocrine or by social housing conditions. The limited variation in agonistic behaviour relative to the endocrine conditions may reflect a non-solitary social organization.     

Male reproductive success and its behavioural correlates in a polygynous mammal,the Galápagos sea lion (Zalophus wollebaeki)

Sexual selection theory predicts competitive males and choosy females. Nevertheless, since molecular marker‐based studies, paternity outside the expected mating patterns has increasingly been described. Even in highly polygynous systems, where paternity is expected to be strongly skewed towards large, dominant males, alternative mating tactics have been suggested. We examined reproductive success in the polygynous Galápagos sea lion (Zalophus wollebaeki). Semiaquatic territoriality allows females to move freely and may lower the degree of polygyny otherwise suggested by both territorial behaviour and strong sexual dimorphism. We assigned paternities with 22 microsatellites and analysed how male reproductive success was related to size, dominance status, intra‐sexual agonistic behaviour, proximity to females, and attendance in the colony. Male behaviour was consistent across two seasons for all parameters under consideration. Attendance was by far the most important determinant of paternal success. Skew in reproductive success towards large, dominant males was weak and dominance status played no role. This appears to be caused by an extremely long reproductive season lasting five or more months, making it difficult for any male to monopolize receptive females. Females seem to choose displaying males that were present in the colony for a long time rather than dominance per se. Sexual dimorphism in Galápagos sea lions may thus be more influenced by selection for fasting than fighting ability. Our data provide further evidence for alternative mating tactics, as several males gained relatively high reproductive success despite short attendance and hardly any involvement in agonistic interactions.     

Extreme natal philopatry in female Antarctic fur seals (Arctocephalus gazella)

Natal philopatry is an important component of mammalian behaviour but is difficult to study in natural vertebrate populations due to the requirement for long-term individual-based spatial observations. Consequently, we quantified fine-scale patterns of natal philopatry in an intensively studied colony of Antarctic fur seals (Arctocephalus gazella), where a scaffold walkway allows individual locations to be measured to the nearest metre. Using subcutaneous PIT tags, we tracked the early life histories of 335 females born within the colony, of which 38 were resighted as breeding adults. We found that individual females returned to as little as one body length (2 m) of their birth locations. Moreover, distances between natal and pupping sites were not correlated with female age, but instead tended to decrease with the number of seasons an individual was sighted ashore. This suggests that breeding experience may be a better predictor than age of the ability of females to occupy preferred sites within fur seal colonies.     

Finescale topographical correlates of behavioural investment in offspring by female grey seals, Halichoerus grypus

Grey seals breed colonially on substrates ranging from ice to rocky or sandy beaches. Clear differences in seal behaviour patterns exist among such broad classes of breeding habitat. However, finer scale topographical variation is likely to influence individual behaviour with consequences for pupping success. We examined topographical influences on the behaviour of breeding female grey seals by quantifying topography at a subseal size resolution. Using submetre resolution digital terrain models of two sites within a rocky breeding colony, we compared site topography in relation to observed differences in female behaviour at these sites. Females at both sites preferred breeding close to water (standing pools or sea) and frequently commuted between their pups and water. Topographical models indicated that one site was more costly for seals in terms of their locations and movements within the site. This was due to a lack of low-elevation land adjacent to the main access points from the sea and the reduced availability of pools. Females at this site showed reduced pup attendance and an increase in energetically costly behaviours, whilst females at the lower-cost site spent more time interacting with their pups and resting. These topographically induced behavioural differences are likely to affect the quantity and quality of pup provisioning by mothers and influence individual pupping site selection. Less costly sites are likely to be colonized preferentially and by larger, older and more dominant females, potentially generating finescale spatial heterogeneity in female quality within the breeding colony. Copyright 2000 The Association for the Study of Animal Behaviour.     

Breeding site fidelity in penduline tit Remiz pendulinus in Southern Hungary

Birds move between breeding locations to gain a better territory, avoid competition or reduce the deleterious effect of inbreeding. We investigated breeding site fidelity in a small European passerine, the penduline tit (Remiz pendulinus). This species has an exceptionally diverse breeding system, in which both males and females may have up to 5–7 mates in a single breeding season, and the eggs are incubated by a single parent: either the male or the female. We investigated the movements of males and females within three breeding seasons in Southern Hungary (2002–2004). Males moved for shorter distances between breeding sites (116 m, 63–333 m; median, lower quartile–upper quartile) than females (942 m, 415–2,382 m). Movements of males and females were consistent between years, and they were repeatable between subsequent nests of males, but not of females. Taken together, our results suggest that adult male penduline tits are more site-faithful than adult females. We suggest that this difference has an implication on their breeding ecology since male parental behaviour (desert/care) is expected to be influenced by local mating opportunities, whilst female parental behaviour is likely to depend on the mating opportunities in a large area around their breeding site.     

Female aggression in red deer: Does it indicate competition for mates?

Female–female competition over mates is often considered of minor importance, particularly in polygynous species. In red deer (Cervus elaphus), female–female aggression within harems during the breeding season has not been studied to date. Herein, we examined if oestrous female red deer in harems show elevated aggression rates, compared to when they are in harems but not in oestrous, and also when they are in foraging groups outside of the breeding season. Any increased levels of aggression involving oestrous females, could indicate the potential for female–female competition for mates in this species. We found that aggressive interactions among female red deer were clearly evident. The most common forms of aggression were displacements, nose threats and kicking. Biting and ear threats occurred less frequently, and chases were rare. There were no differences in the proportion of the different aggression types in the three social contexts. More importantly, we found that the highest overall rates of aggression were for oestrous females in harems, and for females in foraging groups. The lowest rates of aggression were found in harems (when the focal female was not in oestrous). If high rates of aggression also occur when several females are simultaneously in oestrous within single harems, then it is possible that this aggression could affect either mate choice or mating order. These results suggest that female–female competition over mates could play a role in the mating behaviour of red deer.     

Experimental evidence for mutual inter- and intrasexual selection favouring a crested auklet ornament

During the breeding season, female and male crested auklets Aethia cristatella (Alcidae), display similar conspicuous crest ornaments composed of elongated forward-curving feathers on their foreheads. Based on quantifications of brief agonistic interactions at a large breeding colony, we found that crest length was strongly correlated with dominance within both sexes. Across the full range of crest length, individuals with longer crests were dominant over shorter-crested individuals in agonistic interactions involving same-sex adults. Within subadults (2-year-olds of unknown sex), there was a similar trend towards longer-crested individuals being dominant. In agonistic interactions involving individuals of different sex and age, adult males were dominant over adult females and adults were dominant over subadults, regardless of crest length. In an experiment in which we manipulated crest length using life-size realistic models, male auklets that responded were less aggressive to male models with longer crests than to models with normal or shorter crests, confirming that crest length by itself signals dominance status. In a related experiment in which we controlled intrasexual competition, both males and females responded to opposite-sex models with more frequent sexual displays when the models had long crests compared with those having short crests, suggesting that crested auklets also have mating preferences that favour long crest ornaments. Taken together, these results support the idea that the crest ornament is favoured by both intra- and intersexual selection. Copyright 1999 The Association for the Study of Animal Behaviour.     

The crest of the peafowl: a sexually dimorphic plumage ornament signals condition in both males and females

Both male and female peafowl grow crests on top of their head – iridescent blue in males, dull iridescent green and brown in females – but the potential signal function of this plumage ornament is unknown. In this study, peafowl crests were measured in three feral populations, and morphological variation in this ornament was studied in relation to body condition (body mass in relation to tarsus length) and health (white blood cell concentration and ectoparasite load). Prior to the start of the breeding season, male crests are wider with greater pennaceous area, and are more likely to have all feathers grown out compared with female crests. Only crest length changed with measurement date, increasing over time; in males, crest measurements were not related to the extent of train feather development. Crest morphology is a potential signal of individual health and condition in both sexes, but in different ways. In females, the amount of crest plumage grown out to its full extent was related to body condition at the start of the breeding season, whereas in males, the size and pennaceous area of the ornament were related to ectoparasite load. Observations of within‐sex agonistic behaviour suggest a possible role for the crest ornament in status signaling in males, because males that engage in more aggressive interactions tend to have wider crests. There was no evidence for a relation between crest morphology and agonistic behaviour in females.     

Agonistic and grooming behavior of captive crowned lemurs (Lemur coronatus) during the breeding season

Captive breeding of rare and endangered prosimians may be enhanced by an increased understanding of all aspects of their seasonal mating behavior. In this study, the agonistic and grooming behaior of captiveL. coronatus were studied during their annual breeding season. Between October and March, selected aspects of agonistic and grooming behavior of four male-female groups were recorded. Males initiated significantly more allogrooming than females. The frequency of this behavior pattern increased significantly in the weeks of estrus. Females performed significantly more agonistic behavior patterns than males. The mean frequency of agonistic interactions decreased significantly during the breeding season. In successfully reproducing groups males showed much less agonism towards females, than they did in unsuccessful groups. Inter-specific comparisons demonstrated that the patterns of agonistic interactions during the breeding season are very different among closely related species of lemurids. The conclusions drawn from this study are that captive breeding of crowned lemurs may be enhanced by keeping permanent multi-male, multi-female groups.     

Sexual competition in an inbreeding social spider,Stegodyphus dumicola (Araneae: Eresidae)

Summary Sexual competition is shown to occur in the social spiderStegodyphus dumicola (Eresidae). While the secondary sex ratio inS. dumicola was female-biased, the overall operational sex ratio (numbers of breeding males to breeding females over the season) showed no strong female bias. Males matured before females and had a shorter lifespan than the females. Mating took place in the natal colony. Males fought over access to the few mature females available early in the reproductive season, but females appeared to control the duration of mating. Later in the season, some adults of both sexes dispersed alone to breed elsewhere. We conclude that different rates of maturation between the sexes within a colony provide the opportunity for females that mature early in the season to be choosy in selecting a mate and this forces males to compete. Early reproduction may be beneficial for both females and males, because the offspring of females that reproduce early may have a competitive advantage over later (and smaller) offspring in the colony.     

AGONISTIC AND SPACING BEHAVIOUR OF THE NOISY MINER MANORINA MELANOCEPHALA, A COMMUNALLY BREEDING HONEYEATER

The Noisy Miner is a communally breeding Australian honeyeater in which several males feed the offspring of a single female. They reside year-round in colonies, which may number several hundred birds. Miners within colonies unite to mob predators and are successful in defending their colony area against all other species of birds. The species is also highly aggressive intraspecifically. Individuals in a colony in southeastern Queensland were present most of the time in small activity spaces. Most resident males showed extensive overlap of activity space from one season to the next. Males did not defend their activity spaces, so that coalitions of birds occurred whose membership changed with place and time. Certain assemblages of males, termed coteries, were of a more permanent nature. Coterie members showed aggression towards outsiders at border regions. Females' activity spaces were much smaller and less variable than those of males. They showed almost no overlap and were probably maintained by mutual avoidance. Females tended to nest within the activity space they occupied shortly before the breeding period. Thus the spacing of males and females within a colony was quite different. Interactions, often agonistic, were frequent between individuals, between an individual and a group, and between groups. Encounters involving two males in which participants normally lived farther apart were more often agonistic than when participants lived more closely, and more aggression was seen within coteries than between them. When larger groups of birds had agonistic encounters, they more frequently involved birds from different coteries. Very little male-female aggression was seen. Interactions between males and females of different coteries were usually sexual, sometimes involving attempted copulation. Colony sizes are probably too large to permit individual recognition of fellow members, but this could be more likely in coteries. Many males in coteries are doubtless closely related, but outsiders frequently infiltrate them. Coteries are not reproductive units.     

Pre-reproductive alliance formation in female wild house mice (<Emphasis Type="Italic">Mus domesticus</Emphasis>): the effects of familiarity and age disparity

Female house mice (Mus domesticus) are known to perform communal breeding more often with kin than with non-kin partners. When mice are grouped in semi-natural enclosures, related females develop pre-reproductive alliances more frequently than unrelated ones. However, little is known about the behavioural mechanisms and the factors promoting kin preferential cooperative associations in female mice. Here we evaluate the relative importance of familiarity and age disparity on the pre-reproductive development of agonistic behaviour and spatial associations within groups of three related females, freely interacting in semi-natural indoor enclosures. We found that familiarity clearly promoted female alliance formation by reducing aggression and enhancing spatial cohabitation, while genetic relatedness per se did not alleviate the effects of unfamiliarity on female grouping. Older sisters clearly dominated younger ones, even if they had lower body weights, or if they had to confront two allied littermate sisters. Hence, our findings corroborate previous findings on familiarity as a proxy for kin-preferential alliance formation in female mice. Moreover, we observed a strong impact of age stratification on female aggression-mediated dominance development. We suggest that this age effect could be expected from a queuing-for-reproduction view of younger house mouse females.Communicated by I. Schlupp     

Hierarchy,kinship and social interaction among Japanese monkeys (Macaca fuscata)

The study reports the relationship between hierarchy, genetic relatedness and social interaction in captive Japanese macaques. Grooming and proximity were found to be positively related to both dominance rank and degrees of relatedness. Ranks also positively correlated with threats while no relationship was observed between genetic relationships and agonistic interactions. The removal of a-male tightened the male hierarchy while the female hierarchy became relatively loose. Affiliative behaviour became more correlated with ranks than degrees of genetic relatedness. In the absence of α-male, the next dominant male avoided involvement in either agonistic or afliliative interactions with reintroduced animals and group females.     

Variation in Female Grey Seal (Halichoerus grypus) Reproductive Performance Correlates to Proactive-Reactive Behavioural Types

Consistent individual differences (CIDs) in behaviour, indicative of behavioural types or personalities, have been shown in taxa ranging from Cnidaria to Mammalia. However, despite numerous theoretical explanations there remains limited empirical evidence for selective mechanisms that maintain such variation within natural populations. We examined behavioural types and fitness proxies in wild female grey seals at the North Rona breeding colony. Experiments in 2009 and 2010 employed a remotely-controlled vehicle to deliver a novel auditory stimulus to females to elicit changes in pup-checking behaviour. Mothers tested twice during lactation exhibited highly repeatable individual pup-checking rates within and across breeding seasons. Observations of undisturbed mothers (i.e. experiencing no disturbance from conspecifics or experimental test) also revealed CIDs in pup-checking behaviour. However, there was no correlation between an individuals’ pup-checking rate during undisturbed observations with the rate in response to the auditory test, indicating plasticity across situations. The extent to which individuals changed rates of pup-checking from undisturbed to disturbed conditions revealed a continuum of behavioural types from proactive females, who maintained a similar rate throughout, to reactive females, who increased pup-checking markedly in response to the test. Variation in maternal expenditure (daily mass loss rate) was greater among more reactive mothers than proactive mothers. Consequently pups of more reactive mothers had more varied growth rates centred around the long-term population mean. These patterns could not be accounted for by other measured covariates as behavioural type was unrelated to a mother’s prior experience, degree of inter-annual site fidelity, physical characteristics of their pupping habitat, pup sex or pup activity. These findings are consistent with the hypothesis that variation in behavioural types is maintained by spatial and temporal environmental variation combined with limits to phenotype-environment matching.     

Colony and nest site fidelity of the rock shag ( Phalacrocorax magellanicus )

The rock shag (Phalacrocorax magellanicus) is an endemic species from southern Argentina and Chile. In Argentina, the population is distributed along the Patagonian coast in 143 small colonies (5–377 pairs). We studied colony and nest site fidelity of rock shags at Punta Loma, Patagonia, Argentina. We banded 37 adults from December 2001 to June 2003, during two breeding and two non-breeding seasons. Nest site fidelity was extremely high during consecutive breeding and also non-breeding seasons. The high percentage of banded birds residing in the colony in consecutive seasons suggests that rock shags are highly faithful to breeding sites and supports the idea of low post-breeding dispersion.     

Correlates of complete brood failure in blue tits: could extra‐pair mating provide unexplored benefits to females?

Behavioural ecologists have for decades investigated the adaptive value of extra‐pair copulation (EPC) for females of socially monogamous species. Despite extensive effort testing for genetic benefits, there now seems to be a consensus that the so‐called ‘good genes’ effects are at most weak. In parallel the search for direct benefits has mostly focused on the period surrounding egg laying, thus neglecting potential correlates of EPC that might be expressed at later stages in the breeding cycle. Here we used Bayesian methods to analyse data collected over four years in a population of blue tits Cyanistes caeruleus, where no support was previously found for ‘good genes’ effects. We found that broods with mixed paternity experienced less brood failure at the nestling stage than broods with single paternity, and that females having experienced complete brood failure in their previous breeding attempt had higher rates of mixed paternity than either yearling or previously successful females. To better understand these observations we also explored relationships between extra‐pair mating, male and female phenotype, and local breeding density. We found that in almost all cases the sires of extra‐pair offspring were close neighbours, and that within those close neighbourhoods extra‐pair sires were older than other males not siring extra‐pair offspring. Also, females did not display consistent EPC status across years. Taken together our results suggest that multiple mating might be a flexible female behaviour influenced by previous breeding experience, and motivate further experimental tests of causal links between extra‐pair copulation and predation.