An Experimental Study of Predator Recognition in Great Tit Fledglings

Studies of naturally predator-naïve adult birds (finches on predator-free islands) and birds experimentally hand reared in isolation from predators indicate that birds can recognise predators innately; that is, birds show anti-predator behaviour without former experience of predators. To reduce predation risk efficiently during the vulnerable fledgling period, we would predict an innate response to be fully developed when the chicks leave the nest. However, 30-day-old naïve great tit fledglings ( Parus major ) did not respond differently to a model of a perched predator than to a similarly sized model of a non-predator. Although chicks showed distress responses such as warning calls and freezing behaviour, they did not differentiate between the stimuli. In contrast, wild-caught first-year birds (4 mo old) and adults responded differentially to the two stimuli. Lack of recognition of a perched predator might be one explanation for the high mortality rate found in newly fledged great tits. Our results imply that parental care is not only important for food provisioning, but also to reduce predation risk during the time when fledglings are most vulnerable.     

Ranging Patterns of Two Syntopic Howler Monkey Species (Alouatta guariba and A. caraya) in Northeastern Argentina

To avoid competition, ecologically similar and closely related species tend to differ in their patterns of habitat use when they live in sympatry. We compared ranging patterns of brown howler (Alouatta guariba) and black and gold howler (A. caraya) monkeys living syntopically, i.e., co-occurring and overlapping their ranges in the same habitat within the zone of sympatry, in the Atlantic Forest of northeastern Argentina with the objective of evaluating whether their use of space contributes to the avoidance of interspecific competition for food resources. During 12 mo we collected data on the ranging behavior of 2 groups of each howler species. We analyzed annual and seasonal daily path lengths and movement rates, home range size, use and overlap, habitat and vertical strata use, and intergroup encounters. Black and gold howlers traveled farther and faster during the time of relative food abundance (abundant season) than during the time of relative food shortage (lean season), and their movement rates were affected by group identity and increased with the proportion of fruits in the diet. Brown howlers’ traveling patterns were not affected by any of these factors. Home ranges for both species (95% fixed kernel; brown howlers: 31–70 ha, black-and-gold howlers: 17–112 ha) were among the largest recorded for Alouatta. For both species, core areas (50% fixed kernel) were larger for larger versus smaller groups, and decreased in the lean season compared to the abundant season. Both species showed similar patterns of habitat use, except for a slight vertical stratification. Groups of different species overlapped their ranging areas consistently more and responded to one another less aggressively during encounters than groups of the same species, suggesting that interspecific spatial niche separation for these two syntopic species is not occurring. The vertical stratification, as well as a day-to-day avoidance strategy, may be the only responses of species to one another that could reduce the potentially high levels of competition for food suggested by their elevated trophic niche overlap. A high degree of niche overlap may explain the parapatric distribution of howlers and other closely related and ecologically similar species of primates.     

Social interactions among captive brushtail possums (Trichosurus vulpecula)

A biological control strategy relying on a self-disseminating agent may provide the only affordable long-term technique for reducing brushtail possum (Trichosurus vulpecula) numbers throughout New Zealand. The objective of this study was to determine the frequency and patterns of social interactions in single and mixed-sex groups of possums, in order to identify interactions that may assist in the dissemination of biocontrol agents. Thirty-two sexually mature wild-caught possums (16 female, 16 male) were housed in captive groups (of four) in enclosures during the breeding and non-breeding seasons. Groups consisted of either all females, females and males or all males. Four types of social interactions were defined: threats, fights, affiliative and sexual interactions. Interactions only occurred between two animals at one time and were most frequent in the non-breeding season. Within all female groups, possums readily engaged in interactions that had either an agonistic or affiliative nature. Mixed-sex groups interacted less frequently than females, but also engaged in both agonistic and affiliative interactions. In contrast, possums in all male groups rarely interacted, with only a few fights and no affiliative interactions observed. Some mixed-sex dyads appeared to 'associate' during the breeding period. Young were produced by three females that regularly associated with a male and one female that showed little associative behaviour. Given the different interaction patterns observed in each group type, biological control agents that rely on specific interaction patterns for dissemination, are likely to spread at different rates among different possum groups and in different seasons.     

Dietary Flexibility of the Brown Howler Monkey Throughout Its Geographic Distribution

Habitat loss and fragmentation constrain the survival of most forest‐living mammals, particularly strictly arboreal primates. Because fragment size directly affects food availability, primate survival in small fragments may depend on dietary flexibility. Here, we review the literature on the diet of 29 wild groups of Alouatta guariba clamitans inhabiting forest fragments in Brazil and Argentina. We identify general feeding patterns and analyze the influence of fragment size and latitude on diet composition. Brown howlers presented a diet composed of 402 plant species belonging to 227 genera and 80 families. Rarefaction curves suggest that the richness of top food species is similar among groups living in larger (>100 ha), medium (11–100 ha) or small (1–10 ha) fragments. On average, only 12% of the plant species used as food sources by a given group was also consumed by groups from other sites. The shorter the distance between sites, the higher the diet similarity among groups. Despite their diet flexibility, brown howlers spent >80% of the total feeding records on 6–24 species belonging to genera such as Ficus, Zanthoxylum, and Eugenia. Leaves and fruits were the plant items most consumed (65% and 22% of the total feeding records, respectively). Leaf consumption was not affected by fragment size, but it was inversely related to latitude, which may be linked to an increase in the concentration of secondary metabolites in leaves at higher latitudes. We suggest that the ability of brown howlers to exploit a large number of plant food species, including native and exotic trees, shrubs, vines, and lianas, is an important trait that contributes to their survival in highly fragmented habitats along the Atlantic forest. Similar meta‐analyses of data from other howler species are necessary to test whether such dietary flexibility is a genus‐wide pattern. Am. J. Primatol. 75:16‐29, 2013. © 2012 Wiley Periodicals, Inc.     

New Zealand island restoration: seabirds, predators, and the importance of history

New Zealand?s offshore and outlying islands have long been a focus of conservation biology as sites of local endemism and as last refuges for many species. During the c. 730 years since New Zealand has been settled by people, mammalian predators have invaded many islands and caused local and global extinctions. New Zealand has led international efforts in island restoration. By the late 1980s, translocations of threatened birds to predator-free islands were well under way to safeguard against extinction. Non-native herbivores and predators, such as goats and cats, had been eradicated from some islands. A significant development in island restoration in the mid-1980s was the eradication of rats from small forested islands. This eradication technology has been refined and currently at least 65 islands, including large and remote Campbell (11 216 ha) and Raoul (2938 ha) Islands, have been successfully cleared of rats. Many of New Zealand?s offshore islands, especially those without predatory mammals, are home to large numbers of breeding seabirds. Seabirds influence ecosystem processes on islands by enhancing soil fertility and through soil disturbance by burrowing. Predators, especially rats, alter ecosystem processes and cause population reductions or extinctions of native animals and plants. Islands have been promoted as touchstones of a primaeval New Zealand, but we are now increasingly aware that most islands have been substantially modified since human settlement of New Zealand. Archaeological and palaeoecological investigations, together with the acknowledgement that many islands have been important mahinga kai (sources of food) for Maori, have all led to a better understanding of how people have modified these islands. Restoration technology may have vaulted ahead of our ability to predict the ecosystem consequences of its application on islands. However, research is now being directed to help make better decisions about restoration and management of islands, decisions that take account of island history and key drivers of island ecosystem functioning.     

Remembering the good and the bad: memory-based mediation of the food–safety trade-off in dynamic landscapes

Predator–prey interactions are central to fitness as animals simultaneously avoid death and consume resources to ensure growth and reproduction. Along with direct effects, predators can also exert strong non-consumptive effects. For example, prey shift habitat use in the presence of predators, a potentially learned behavior. The impact of cognition on movement and predator interactions is largely unexplored despite evidence of learned responses to predation threat. We explore how learning and spatial memory influence predator–prey dynamics by introducing predators into a memory-driven movement modeling framework. To model various aspects of risk, we vary predator behavior: their persistence and spatial correlation with the prey’s resources. Memory outperforms simpler movement processes most in patchy environments with more predictable predators that are more easily avoided once learned. In these cases, memory aids foragers in managing the food–safety trade-off. For example, particular parameterizations of the predation memory reduce encounters while maintaining consumption. We found that non-consumptive effects are highest in landscapes of concentrated, patchy resources. These effects are intensified when predators are highly correlated with the forager’s resources. Smooth landscapes provide more opportunities for foragers to simultaneously consume resources and avoid predators. Predators are able to effectively guard all resources in very patchy landscapes. These non-consumptive effects are also seen with the shift away from the best quality habitat compared to foraging in a predator-free environment.     

Intragroup Social Relationships of Male Alouatta palliata on Barro Colorado Island,Republic of Panama

We examined social and spatial relations of adult males in one group of mantled howling monkeys (Alouatta palliata) on Barro Colorado Island (BCI) in central Panama to document patterns of association. Beyond the existence of an alpha male, we could not distinguish any linear dominance hierarchy among the 6 study males. All males copulated with estrous females. Our findings contrast with reports of intragroup male behavior in Costa Rican howlers. Study males engaged in little or no affiliative or agonistic behavior with one another, but engaged in significantly more such interactions with females. The alpha male, the oldest male and a younger male were most frequently in association with females. Of group males, the oldest male associated significantly more with other males. Overall, male behavior in mantled howling monkeys on BCI generally followed the van Hooff and van Schaik (1994) model of male relationships. The low incidence of intragroup social interactions of any type in the focal males may reflect the energetic costs of social behavior. We suggest that intragroup social relationships among mantled howler males are structured by more subtle means than overt physical interactions, possibly including vocal communication, relationships with individual group females, and kinship.     

Roaring Behavior of Two Syntopic Howler Species (Alouatta caraya and A. guariba clamitans): Evidence Supports the Mate Defense Hypothesis

Long-distance calls are loud vocalizations involved in within and between group communication in animals. These calls may maintain cohesion with group members or communicate the ownership of valuable resources such as territory, food, or mates to individuals from other groups. In howlers (Alouatta spp.), three nonmutually exclusive hypotheses suggest that the ultimate function of roaring (howling) behavior is to protect resources from neighboring groups. The space/food defense hypothesis maintains that roars are used to gain exclusive access to food; the mate defense hypothesis holds that roars ensure exclusive access to mates; and the infanticide avoidance hypothesis states that the roaring behavior serves to avoid male takeovers and infanticide. To test these three hypotheses, we conducted a study on black-and-gold howlers (Alouatta caraya) and brown howlers (A. guariba clamitans) living in syntopy at El Pi?alito provincial park in northeast Argentina. We recorded 12 mo of data on the roaring behavior of two groups of each species, along with data on food availability and diet. Although all four groups overlapped extensively in their use of food resources during the study period, roars occurred much more frequently during interactions between groups of the same species than between groups of different species. Roaring frequency was not higher during the lean season, when high-quality food was less abundant. Howlers did not roar more frequently at home range boundaries, nor were roaring bouts spatially associated with valuable feeding resources. Males participated in all of the roaring bouts, whereas females participated in only 29% of them. Adults did not roar more frequently when there were unweaned infants in the group, as expected if roaring behavior decreases infanticide risk. These results provide no support for the food defense or infanticide avoidance hypotheses, but support predictions derived from the mate defense hypothesis.     

Forest Fragmentation Modifies Habitat Quality for Alouatta palliata

Fragmentation reduces habitat area, increases the number of habitat patches, decreases their size, and increases patch isolation. For arboreal mammals such as howlers (Alouatta palliata), canopy modifications from fragmentation processes could also negatively affect habitat quality. We analyzed changes in the composition and plant structure of 15 fragments (1–76 ha) and compared them with vegetation from a continuous tropical rain forest reserve (700 ha) in Los Tuxtlas, Mexico. At each site, we sampled 1000 m² of all trees, shrubs, and lianas with a diameter at breast height (DBH) ≥10 cm. We obtained estimates of species richness, density, and basal area for different ecological groups, DBH ranges, and top food resources for howlers. We used a stepwise multiple regression analysis to determine relationships between fragment characteristics (size, shape index, and isolation) and plant variables. Compared to continuous forest, fragments have altered composition and plant structure, with large trees absent from the canopy. The basal area of top food resources is higher in continuous forest. Fragment size is the best explanation for the differences in composition and plant structure. The largest fragments had greater basal area of top food resources and more large primary trees in the canopy. Overall, our results suggest that fragmentation altered the habitat quality for howlers.     

Establishment of a free-ranging colony of Stumptail macaques (Macaca arctoides): Relations to the ecology I

A group of 20 Stumptail macaques was released free on the island of Totogochillo in lake Catemaco, Veracruz, Mexico, on August 15 of 1974. Initial adaptations to the island geography and ecology are reported for the first 83 days of observation. The island of Totogochillo is a lava formed island with vegetation type consisting of secondary tropical rain forest. The Stumptail group composition consisted of one adult male, five adult female and 14 non adult individuals. Individuals and matrilineal genealogies are identifiable. Home range is limited by the island's size. The macaques only have one sleeping site. The use of resting areas seems to be related to variations in the travelling and foraging patterns of the Stumptails. Five travelling routes have been identified and changes in these are associated to changes in the availability and distribution of natural edibles. Feeding adaptations consitst of consumption of vegetal matter such as leaves, seeds, roots, flowers, and tree bark. Of 65 major plant species identified the Stumptails consume 28% (N: 18). Sex differences in foods eaten were not observed but age differences do exist. The macaques prey on crickets, spiders, birds, and water snails. A food pressures is suggested to induce the monkeys to locate new food resources. Predators on the island are not existent but avian predators are present in the area. The Stumptails respond to their presence with alarm calls and an attack by a hawk on the group was witnessed. Sentinele behaviour was performed by an adult female while protecting and scouting were carried out by the adult male in the group. During the course of the study four deaths occurred, two infants were born and on November 7th, 12 more Stumptails were released on the island. Continuing research consists of studies of the ontogeny of social relations and of the sexual behaviour in the Stumptail group against a background of known social structural relations and kinship ties. This work was supported by grants from Behavioral Sciences Foundation and by NSF-No. GB42235.     

Why are some weta (Orthoptera: Stenopelmatidae) vulnerable yet others are common?

The large (4 g) to very large (40 g) stenopelmatid orthopterans of New Zealand are known collectively as weta. A consideration of 20 species of Hemideina, Deinacrida and tusked weta reveals that at one end of a vulnerability gradient are those species which thrive in the presence of key predators (rats), while at the other end are species that have become extinct on the mainland but still survive on predator-free island refuges. Habitat modification does not appear to be a factor in these extinctions. This paper reviews the lifestyles and some important biotic parameters that seem to determine their relative vulnerability along this gradient. When predators are present, the factors leading to extinction are large body size, use of temporary refuges, protective quality of the refuges, time spent on the ground and the effectiveness of their defensive behaviour.     

An examination of a compensatory relationship between food limitation and predation in semi-domestic reindeer

A central issue in ecology is to what extent food limitation and predation affect animal populations. We studied how survival and reproductive success was related to the female's size in a population of semi-domesticated reindeer during 2 years where there was a large difference in snowfall during winter. The females were kept within a predator-free enclosure for about 5 weeks during the calving period and thereafter released to their natural summer pastures. Small females were more likely to fail to reproduce and they produced smaller calves than large females. Additionally, small females were more likely to loose their calves due to starvation within the predator-free enclosure and to predators outside the enclosure. Food limitation during the harsh winter appeared to be the major cause of deaths. However, food limitation interacted with predation and led to high calf losses when the females experienced low food availability during the harsh winter. In contrast, predators killed no calves after the mild winter. Apparently, the interaction between predation and food limitation is due to small females favouring their own growth and survival over calf production in summers following harsh winters with food shortage. Our results indicate that a compensatory relationship exists between mortality due food limitation and predation. Thus, the impact of calf predation on reindeer demography and population dynamics may be limited.     

Grooming,kinship, and co‐feeding in captive spider monkeys (Ateles geoffroyi)

Allo‐grooming is perhaps the most powerful affiliative behavior observed in non‐human primates. However, the functional significance of grooming in New World monkeys has not yet been fully understood, perhaps because grooming is less frequently observed in platyrrhines. To differentiate the potential role of affiliative investment and/or kinship on sharing access to food (co‐feeding) in spider monkeys, behavioral data on grooming, embracing, and feeding were collected from two different groups of captive study subjects: a familiar/kin group and a non‐familiar/non‐kin group. The results of this study suggest that family‐related spider monkeys that engage in grooming tend to share access to food resources more than unfamiliar conspecifics that do not groom. One explanation for this difference is that the unfamiliar study subjects had not yet invested in the affiliative social network, were not reciprocating their affiliative investments and hence, had a higher tendency toward single animal monopolizing resources. Degree of relatedness alone was not found to be a determinant for sharing the access to food, suggesting that familiarity in spider monkeys is based on the extent to which animals invest in affiliative relationships. In this study, only animals that had engaged in long‐term grooming and recognized each other as familiar shared the access to food. Therefore, it might be likely that in spider monkeys, long‐term grooming of high intensity has to be developed for co‐feeding to occur. Zoo Biol 20:293–303, 2001. © 2001 Wiley‐Liss, Inc.     

Foraging Behavior and Activity Patterns of Alouatta caraya in the Northeastern Argentinean Flooded Forest

Howling monkeys (Alouatta spp.) are colonizer species, showing a plasticity in behavior that allows them to inhabit different sorts of forests. There is a series of hypotheses relating demography to behavioral and ecological characteristics of howlers: (1) as howler density increases, home range size will decrease; (2) howler groups occupying small home ranges will have a high proportion of leaves in their diet; and, (3) the proportion of mature leaves in the diet is negatively correlated with group daily travel distance. To test hypotheses about howler diet and ranging pattern in relation to food resources, we studied the foraging ecology and general activity patterns of 2 groups of black howlers (Alouatta caraya) inhabiting in flooded forest of Paraná River (Argentina), the habitat with the highest density recorded for Alouatta. We found, in addition to the highest densities, also the smallest home ranges for Alouatta (Group I: 1.7 ha and Group II: 2.2 ha). However, diet was not dominated by leaves, and high quality items—flowers, fruits, new leaves—were a high proportion of the diet all year. Also, daily travel distance is not correlated with the proportion of mature leaves in the diet, but is positively correlated with the number of group confrontations. Finally, we propose a model integrating and interpreting our results as a function of the spatial and temporal distribution of high quality food resources in the Argentinean flooded forest.     

Alien predators are more dangerous than native predators to prey populations

Alien predators are widely considered to be more harmful to prey populations than native predators. To evaluate this expectation, we conducted a meta-analysis of the responses of vertebrate prey in 45 replicated and 35 unreplicated field experiments in which the population densities of mammalian and avian predators had been manipulated. Our results showed that predator origin (native versus alien) had a highly significant effect on prey responses, with alien predators having an impact double that of native predators. Also the interaction between location (mainland versus island) and predator origin was significant, revealing the strongest effects with alien predators in mainland areas. Although both these results were mainly influenced by the huge impact of alien predators on the Australian mainland compared with their impact elsewhere, the results demonstrate that introduced predators can impose more intense suppression on remnant populations of native species and hold them further from their predator-free densities than do native predators preying upon coexisting prey.     

Interactions between gray-sided voles (<Emphasis Type="Italic">Clethrionomys rufucanus</Emphasis>) and bilberry (<Emphasis Type="Italic">Vaccinium myrtillus</Emphasis>), their main winter food plant

We compared the abundance, population structure and palatability of bilberry ramets on vole-free islands, islands with voles but no predators (predator-free islands) and mainland sites with both voles and predators. As expected, bilberry biomass was strongly correlated with the herbivory pressure exerted by the voles, since it was significantly lower on the mainland, and much (>80%) lower on the predator-free islands, than on the vole-free islands. However, another finding, which conflicts with hypotheses postulating that herbivory generally induces plant defenses, was that voles preferred ramets from predator-free islands. Bilberry plants were fairly tolerant to grazing since they compensated for some of the lost tissue by producing more new ramets. This response should promote stability in the plant–herbivore interaction by reducing the impact of past grazing on current food production and thus minimizing time delays in the interactions that could potentially generate population cycles.     

Hunt or hide: How insularity and urbanization affect foraging decisions in lizards

Foraging decisions should reflect a balance between costs and benefits of alternative strategies. Predation risk and resource availability in the environment may be crucial in deciding how cautious individuals should behave during foraging. These costs and benefits will vary in time and context, meaning that animals should be able to adjust their foraging behaviour to new or altered environments. Studying how animals do this is essential to understand their survival in these environments. In this study, we investigated the effect of both insularity and urbanization on risk‐taking and neophobia during foraging in the Dalmatian wall lizard (Podarcis melisellensis). Small islets tend to have both a lower number of predators and less resources. Therefore, islet populations were expected to show more risk‐taking behaviour and less neophobia in a foraging context. Previous studies on behaviour of urban lizards have yielded inconsistent results, but due to a lack of both predators and arthropod prey in urban habitats, we expected urban lizards to also take more risks and behave less neophobic. We sampled several inhabited and uninhabited locations on Vis (Croatia) and surrounding islets. Risk‐taking behaviour was tested by measuring the latency of lizards to feed in the presence of a predator model, and neophobia by measuring the latency to feed in the presence of a novel object. We found that islet lizards do indeed take more risks and were less vigilant, but not less neophobic. Urban and rural lizards did not differ in any of these behaviours, which is in sharp contrast with previous work on mammals and birds. The behavioural differences between islet and island lizards were novel, but not unexpected findings and are in line with the theory of “island tameness”. The effect of urbanization on the behaviour of animals seems to be more complex and might vary among taxa.     

Feeding Strategies of Brown Howler Monkeys in Response to Variations in Food Availability

Primates display varying degrees of behavioral flexibility that allow them to adjust their diet to temporal changes in food availability. This trait might be critical for the survival of folivorous-frugivorous species inhabiting small forest fragments, where the availability of food resources tends to be lower than in large fragments and continuous forests. However, the scarcity of studies addressing this issue hampers our understanding of the adaptive behaviors that favor the survival of these primates in low-quality habitats. We conducted a 36-mo study testing the hypothesis that brown howler monkeys (Alouatta guariba clamitans) are able to adjust their diet in response to local and seasonal changes in resource availability. We compared the diet of six free-ranging groups inhabiting three small (<10 ha) and three large (>90 ha) Atlantic forest fragments in southern Brazil and estimated the temporal availability of their top food species (i.e., those species that together contribute ≥80% of total feeding records). We found that brown howlers exploited similarly rich diets in small (45, 54, and 57 plant species) and large (48, 51, and 56 species) fragments. However, intermonth diet similarity was higher for groups in small fragments, where howlers also fed on plant items from nine alien species. Fruits and leaves were the most consumed plant items in both small (42% and 49% of feeding records, respectively) and large (51% and 41%, respectively) fragments. The consumption of young leaves was higher in small than in large fragments, whereas the consumption of other plant items did not show a pattern related to fragment size. Regarding the contribution of growth forms as food sources, only the exploitation of palms showed a pattern related to fragment size. Palms contributed more to the diet of groups inhabiting large fragments. The availability of seasonal food items–ripe fruits and young leaves–influenced their consumption in both habitat types. Therefore, brown howlers cope with local and seasonal fluctuations in food availability by opportunistically exploiting resources. We believe that this feeding flexibility is a key component of the phenotypic plasticity that enables howlers to thrive in disturbed habitat patches, where periods of scarcity of preferred foods shall be more common.     

Experimental Manipulation of Food Accessibility Affects Conflict Management Behaviour in Ravens

Conflict management strategies such as reconciliation and bystander affiliation have been described for a variety of species. A common determinant seems to be a ‘complex’ social life, with individuals relying on affiliate relationships or social bonds. Little is known, however, about the strategic and flexible use of conflict management skills in experimental settings in species other than primates. We here investigated conflict and post‐conflict behaviour of ravens by manipulating the accessibility of food and, thus, the likelihood of aggressive interactions while foraging. Specifically, we presented birds with a certain amount of highly preferred food that varied in the number of pieces (one piece, two pieces or, as a control, small pieces matching the number of participating birds) and observed their agonistic behaviour during feeding and their affiliative behaviour afterwards. The results showed that high levels of conflicts during feeding in the 1‐piece and 2‐piece conditions led to high levels of affiliation after feeding. Depending on the experimental condition, this effect is best explained (a) by the affiliative behaviour of former aggressors (1‐piece condition) and (b) by the affiliation directed to the receivers of aggression after feeding (2‐piece condition). Those dyads that engaged in allo‐preening after feeding also engaged in allo‐preening outside the experimental setting, suggesting that socially bonded individuals provided third‐party affiliation to victims of aggression. Moreover, socially bonded ravens fed close to each other in the experiment when food was clumped, indicating that they actively coordinated their behaviour when there was a high conflict potential. Taken together, these findings support the assumption that ravens use their social bonds to avoid conflicts by choosing with whom to feed, and to buffer effects of conflicts by engaging in third‐party affiliation as post‐conflict behaviour.     

Post-Conflict Affiliation in Barbary Macaques is Influenced by Conflict Characteristics and Relationship Quality, but Does Not Diminish Short-Term Renewed Aggression

Many group living primates have evolved mechanisms to repair their social relationships after conflicts ('reconciliation'). We analysed the post-conflict behaviour of female Barbary macaques, Macaca sylvanus , living in the enclosure 'La Forêt des Singes' at Rocamadour, France. Based on a sample of 914 conflicts, we investigated whether relationship (kinship, rank, affiliation, support and sex) and conflict characteristics (conflict intensity, context and duration) affected the quality and frequency of affiliative post-conflict interactions. Thirty-two per cent of all conflicts were followed by post-conflict affiliation. Rates of socio-positive interactions and support were better predictors of post-conflict affiliation than kinship or rank. Short conflicts were followed by post-conflict affiliation relatively more frequently, after a shorter latency, but only briefly, and such interactions were initiated by both parties equally frequently. The majority of affiliative post-conflict interactions occurred immediately after the end of the conflict. In sum, female Barbary macaques invest more in post-conflict affiliation with valuable partners, and they modulate their post-conflict behaviour in relation to conflict characteristics. Remarkably, affiliative post-conflict interactions increased the short-term probability of renewed aggression by the former aggressor to 16% compared with 9% for conflicts that were not followed by affiliative behaviour. Such renewed aggression after post-conflict affiliation occurred particularly frequently among females and after conflicts over food, suggesting that post-conflict affiliation sometimes falsely lures the former victim to stay in the vicinity, even at the risk of receiving renewed aggression.