Interspecific Social Information Research Articles

Social learning of acoustic anti-predator cues occurs between wild bird species.

In many species, individuals gather information about their environment both through direct experience and through information obtained from others. Social learning, or the acquisition of information from others, can occur both within and between species and may facilitate the rapid spread of antipredator behaviour. Within birds, acoustic signals are frequently used to alert others to the presence of predators, and individuals can quickly learn to associate novel acoustic cues with predation risk. However, few studies have addressed whether such learning occurs only though direct experience or whether it has a social component, nor whether such learning can occur between species. We investigate these questions in two sympatric species of Parids: blue tits (Cyanistes caeruleus) and great tits (Parus major). Using playbacks of unfamiliar bird vocalizations paired with a predator model in a controlled aviary setting, we find that blue tits can learn to associate a novel sound with predation risk via direct experience, and that antipredator response to the sound can be socially transmitted to heterospecific observers, despite lack of first-hand experience. Our results suggest that social learning of acoustic cues can occur between species. Such interspecific social information transmission may help to mediate the formation of mixed-species aggregations.

Social information drives ecological outcomes among competing species.

Through its behavior, an organism intentionally or unintentionally produces information. Use of this "social information" by surrounding conspecifics or heterospecifics is a ubiquitous phenomenon that can drive strong correlations in fitness-associated behaviors, such as predator avoidance, enhancing survival within and among competing species. By eliciting indirect positive interactions between competing individuals or species, social information might alter overall competitive outcomes. To test this potential, we present new theory that quantifies the effect of social information, modeled as predator avoidance signals/cues, on the outcomes from intraspecific and interspecific competition. Our analytical and numerical results reveal that social information can rescue populations from extinction and can shift the long-term outcome of competitive interactions from mutual exclusion to coexistence, or vice versa, depending on the relative strengths of intraspecific and interspecific social information and competition. Our findings highlight the importance of social information in determining ecological outcomes.

Interspecific information on predation risk affects nest site choice in a passerine bird

BackgroundBreeding site choice constitutes an important part of the species niche. Nest predation affects breeding site choice, and has been suggested to drive niche segregation and local coexistence of species. Interspecific social information use may, in turn, result in copying or rejection of heterospecific niche characteristics and thus affect realized niche overlap between species. We tested experimentally whether a migratory bird, the pied flycatcher Ficedula hypoleuca, collects information about nest predation risk from indirect cues of predators visiting nests of heterospecific birds. Furthermore, we investigated whether the migratory birds can associate such information with a specific nest site characteristic and generalize the information to their own nest site choice.ResultsOur results demonstrate that flycatchers can use the fate of heterospecific nesting attempts in their own nest site choice, but do so selectively. Young flycatcher females, when making the decision quickly, associated the fate of an artificial nest with nest-site characteristics and avoided the characteristic associated with higher nest predation risk.ConclusionsCopying nest site choices of successful heterospecifics, and avoiding choices which led to failed attempts, may amplify or counter effects of nest predation on niche overlap, with important consequences for between-species niche divergence-convergence dynamics, species coexistence and predator-prey interactions.

Understanding how mammalian scavengers use information from avian scavengers: cue from above.

Interspecific social information transfer can play a key role in many aspects of animal ecology from foraging to habitat selection to predator avoidance. Within scavenging communities, avian scavengers often act as producers and mammalian scavengers act as scroungers, but we predict that species-specific cueing will allow for mammalian scavengers to utilize particular avian scavenger species using preferred food sources similar to their own preferences. We use empirical and theoretic approaches to assess interactions between mammalian and avian scavengers in one of the most diverse scavenging guilds in Masai Mara National Reserve, Kenya. Using a spatially explicit model and data from experimental carcasses, we found evidence that mammals benefit from local enhancement provided by vultures and that mammalian-avian following patterns are consistent with the idea that species-specific cueing is occurring. Results suggest that ongoing population declines in avian scavengers may have significant impacts on mammalian scavengers and potentially create trophic cascades.

Interspecific social information use in habitat selection decisions among migrant songbirds

The presence of conspecifics is a social cue frequently used by songbirds in breeding-site selection. In migratory species, conspecific attraction is not possible for individuals that arrive first to breeding grounds, but these individuals may use information from ecologically similar heterospecifics. Resident tits (Paridae) are known to provide cues for migratory songbirds, however, the relevance of resident settlement decisions decreases as the season progresses. We investigated heterospecific attraction within migrant songbirds, and examined whether later arriving species use the presence of earlier arriving species as a cue for breeding habitat selection. We used a song playback experiment to test if wood warbler Phylloscopus sibilatrix settlement decisions are affected by chiffchaff Phylloscopus collybita and blackcap Sylvia atricapilla cues. Our results suggest that wood warblers used cues from heterospecifics when deciding where to breed. Wood warblers settled earlier and more numerously on plots with simulated presence of chiffchaffs, in contrast blackcap presence had a negative effect on settlement, suggesting heterospecific avoidance. Chiffchaffs and blackcaps were attracted to sites with simulated presence of conspecifics, which provides evidence for conspecific attraction in breeding-site selection of these species. Our experiment suggests that heterospecific attraction is not a phenomenon limited to resident-migrant interactions, but acts also between migrant species. Our results show an interplay of attraction and avoidance when using social cues for habitat selection decisions within a migrant songbird guild, and stress the importance of both positive and negative effects of social environment on settlement behaviour of individuals.

The use and relative importance of intraspecific and interspecific social information in a bird community

Lay Summary Information from conspecifics outweighs other information sources for collared flycatchers making their nest site choices late in the spring. Collared flycatchers copy the nest site characteristics apparently chosen by earlier settled flycatchers and competing tits. When the apparent decisions of the fellow flycatchers and competing tits are in conflict, flycatchers copy conspecifics when conspecifics outnumber the competitors, which is the case late in the spring.

Avoiding perceived past resource use of potential competitors affects niche dynamics in a bird community.

BackgroundSocial information use is usually considered to lead to ecological convergence among involved con- or heterospecific individuals. However, recent results demonstrate that observers can also actively avoid behaving as those individuals being observed, leading to ecological divergence. This phenomenon has been little explored so far, yet it can have significant impact on resource use, realized niches and species co-existence. In particular, the time-scale and the ecological context over which such shifts can occur are unknown. We examined with a long-term (four years) field experiment whether experimentally manipulated, species-specific, nest-site feature preferences (symbols on nest boxes) are transmitted across breeding seasons and affect future nest-site preferences in a guild of three cavity-nesting birds.ResultsOf the examined species, resident great tits (Parus major) preferred the symbol that had been associated with unoccupied nest boxes in the previous year, i.e., their preference shifted towards niche space previously unused by putative competitors and conspecifics.ConclusionsOur results show that animals can remember the earlier resource use of conspecifics and other guild members and adjust own decisions accordingly one year after. Our experiment cannot reveal the ultimate mechanism(s) behind the observed behaviour but avoiding costs of intra- or interspecific competition or ectoparasite load in old nests are plausible reasons. Our findings imply that interspecific social information use can affect resource sharing and realized niches in ecological time-scale through active avoidance of observed decisions and behavior of potentially competing species.

Observed Fitness May Affect Niche Overlap in Competing Species via Selective Social Information Use

Social information transmission is important because it enables horizontal spread of behaviors, not only between conspecifics but also between individuals of different species. Because interspecific social information use is expected to take place among species with similar resource needs, it may have major consequences for the emergence of local adaptations, resource sharing, and community organization. Social information use is expected to be selective, but the conditions promoting it in an interspecific context are not well known. Here, we experimentally test whether pied flycatchers (Ficedula hypoleuca) use the clutch size of great tits (Parus major) in determining the quality of the observed individual and use it as a basis of decision making. We show that pied flycatchers copied or rejected a novel nest site feature preference of great tits experimentally manipulated to exhibit high or low fitness (clutch size), respectively. Our results demonstrate that the social transmission of behaviors across species can be highly selective in response to observed fitness, plausibly making the phenomenon adaptive. In contrast with the current theory of species coexistence, overlap between realized niches of species could dynamically increase or decrease depending on the observed success of surrounding individuals.

Facing Uncertainty: How Small Songbirds Acquire and Use Social Information in Habitat Selection Process?

Habitat selection is a decision-making process that birds use to select a habitat in which they live. It is crucial for individuals to make the correct choices, because their living space directly affects their fitness. When making settlement decisions, birds are faced with uncertainty about habitat quality. In order to reduce it, they have to acquire information, which makes their world more predictable. Acquisition and use of information about habitat quality is the central part of the habitat selection process. Individuals can acquire information about habitat quality in various ways, e.g., by using own breeding experience (personal information), or by observing behavior and decisions made by other individuals (social information). In this review I briefly described the types of social information which songbirds use to assess the habitat quality. By using unified approach, I evaluated their value and availability for individuals, concluding that simultaneous use of several types of information provide the most effective way to habitat quality assessment. Furthermore, I argued why tits (Paridae) constitute a crucial link in the chain of interspecific social information transfer within songbirds’ communication networks throughout the Holarctic and suggested that they may be considered as the keystone cue-providers. Moreover, I evaluated current literature on the artificial-attraction methods and highlighted urgent research needs in context of its practical application in the conservation and management of songbirds populations.

Experimental evidence for the use of density based interspecific social information in forest birds

Reproductive success and habitat preference are generally assumed to be negatively associated with densities of con‐ and heterospecific competitors. However, recent theoretical studies have suggested that in some cases habitat preference may have a nonlinear unimodal function in relation to con‐ or heterospecific competitor densities – intermediate densities being preferred. Such a pattern is expected if con‐ or heterospecific densities are used as a proximate cue in habitat selection, which may produce benefits by reducing searching costs and providing information about current habitat quality and costs of competition. At low density the use of such cues, and hence habitat selection, are hampered, whereas at high density costs of competition exceed the benefits of using cues, leading to avoidance. Here, we tested this hypothesis by examining whether arboreal migratory birds use the density of resident titmice (Parusspp.) in habitat selection decisions. Many migrants and titmice species share similar resource needs making titmice density a reliable source of information for migrants. At the scale of habitat patches, we experimentally created a range of titmice densities from low to very high and subsequently measured the density response of migrants. In contrast to the unimodal habitat preference hypothesis, the average species number and total density of migratory birds were positively and linearly correlated with manipulated titmice density. Thus, migrants probably use titmice density as a relative indicator of habitat quality (abundance or quality of food) because foliage gleaners that share similar food resource with titmice, but not ground foragers, showed a positive association with manipulated titmice density. These results emphasize the positive effect of interspecific social information on habitat choice decisions and diversity of migratory bird community.

Mechanisms and fitness effects of interspecific information use between migrant and resident birds

Interactions with potential competitors are an important component of habitat quality. Due to the costs of coexistence with competitors, a breeding habitat selection strategy that avoids competitors is expected to be favored. However, many migratory birds appear to gain benefits from an attraction to the presence of resident birds, even though residents are assumed to be competitively dominant. Thus far the mechanisms of this habitat selection process, heterospecific attraction, are unknown, and the consequences for resident birds of migrant attraction remain untested. Through heterospecific attraction, migrants may gain benefits if the density or territory location of residents positively reflects habitat quality, and/or they gain benefits through increased frequency of social interactions with residents in foraging or predator detection. In this experiment, we examined the reciprocal effects of spatial proximity on fitness-related traits in migrant pied flycatcher (Ficedula hypoleuca) and resident great tit (Parus major) by experimentally forcing them to breed either alone or in close proximity to each other. Surprisingly, great tits bore all the costs of coexistence while flycatchers were unaffected, even gaining slight benefits. In concert with an earlier study, these results suggest that flycatchers use tits as information about good-quality nest-site locations while benefits from social interactions with tits are possible but less important. We suggest that utilizing interspecific social information may be a common phenomenon between species sharing similar resource needs. Our results imply that the effects of interspecific information use can be asymmetric and may therefore have implications for the patterns and consequences of species coexistence.