Cognitive ecology – ecological factors, life-styles and cognition

Cognitive ecology integrates cognition, ecology and neurobiology in one topic and has recently broadened into an exciting diversity of themes covering the entire range of cognition and ecological conditions. The review identifies three major environmental factors interacting with cognition: environmental variation (predictable and unpredictable), environmental complexity and predation. Generally, variable environments favour cognitive abilities such as exploration, learning, innovation, memory and also result in larger brains as compared to stable environments. Likewise, cognition is enhanced in complex versus simple environments, whereas the relationship between predation and cognitive abilities can be positive or negative. However, organisms have often evolved entire life-styles (e.g. residency vs migration, food-caching vs non-caching, generalism vs specialism) to deal with these environmental factors. Considering cognition within this framework provides a much more diverse picture of how cognitive abilities evolved in conjunction with other adaptations to environmental challenges. This integrated approach identifies gaps of knowledge and allows the formulation of hypotheses for future testing. Several recently emerged approaches study cognitive abilities at a new and in part highly integrated level. For example, the effect that environment has on the development of cognitive abilities during ontogeny will improve our understanding about cause and effect and gene x environment interactions. Together with two recently emerged highly integrative approaches that link personality and pace-of-life syndromes with cognitive ecology these new directions will improve insight how cognition is interlinked with other major organisational processes

Personality traits in resident and migratory warbler species.

Animals are often confronted with environmental challenges and the way in which they cope with these challenges can have important fitness consequences. There is increasing evidence that individuals differ consistently in their reaction to the environment (personality traits). However, little is known about whether different life-styles (e.g., resident or migratory) influence personality traits and if so, in what manner. We compared neophobic and exploratory behaviours, both of which play an important role in personality traits, between two closely related species, the resident Sardinian warblers and the migratory garden warblers, at two different times during the year. Neophobia was tested by placing a novel object, a mop, beside the feeding dish and measuring the latency to feed (neophobia score). Exploration was tested by offering another novel object, a tube, attached to a perch at a neutral location and measuring latency to approach and investigate the tube (exploration score). Both tests were carried out at the end of the breeding season and repeated ten months later in spring. The Sardinian warblers showed consistent behavioural reactions over time. Furthermore, neophobia and exploration scores were negatively related. The garden warblers neither behaved consistently over time nor was there a correlation between neophobia and exploration. Overall, Sardinian warblers were less neophobic and more explorative than garden warblers. The different reactivity may be due to a different frequency distribution of the individuals of the two species along a reactivity axis. It can be concluded that the Sardinian warblers have personality traits. The situation is less clear in the garden warblers. Possibly, different life-styles require different organisation of behaviours

Residency and a broad feeding spectrum are related to extensive spatial exploration in parrots

Resident and nomadic species differ substantially in their mobility, with the former spending most of their lives in a restricted area and the latter encountering many areas while tracking spatiotemporal unpredictable resources. Earlier studies have shown that information gathering differs alongside this mobility axis—resident species pay more attention to changes in their familiar environment than nomadic ones. However, little is known about spatial exploration in resident and nomadic species. We investigated spatial exploration in 10 closely related parrot species that differed in their mobility by giving them access to two unfamiliar aviaries left and right of the familiar aviary. For analyses, mobility and some diet and habitat variables were related to spatial exploration. Nomadic species spent less time exploring the novel aviaries and also started tactile exploration later than resident/nomadic and pure resident species. Furthermore, diet specialists visited more new locations in relation to their overall movements than diet generalists. The variables were not correlated with the molecular phylogeny (mitochondrial cytochrome b) of the species. The results indicate that nomads invest less in spatial exploration than residents possibly because they stay only for limited periods of time in one particular area or use easier-to-assess cues. Residents, in contrast, assess a novel environment in detail as they may collect information about future breeding sites for which they need short- and long-term information. Finally, diet specialists may pay attention to fewer environmental cues than generalists, which allows them to move faster through a novel environment

When to return to normal? Temporal dynamics of vigilance in four situations

Vigilance is an important behaviour to monitor the environment from detecting predators to tracking conspecifics. However, little is known about how vigilance changes over time either without disturbance (vigilance decrement) or after a change occurred. The time course of vigilance can indicate how animals perceive a situation and the potential mechanism used to deal with it. I investigated the time course of vigilance in Gouldian Finches in four situations (familiar environment, two changed environments – novel object at a neutral location (exploration trial) or above the feeder (neophobia trial), novel environment). The frequency of head movements was assessed in four consecutive 15-minute blocks in same sex pairs with a high frequency generally seen as indicative of high vigilance. Vigilance decreased over time in the familiar situation in-dicating vigilance decrement with a similar time course in the exploration trial. Vigilance was consistently high in the neophobia trial and only returned to normal in the last block. Finally, vigilance plummeted in the novel environment and did not return to normal within an hour. Results suggest that perceived threats affected vigilance and that information gathering reduced uncertainty allowing vigilance to return to normal levels but with different time courses depending on the situation

Energy Reserves, Information Need and a Pinch of Personality Determine Decision-Making on Route in Partially Migratory Blue Tits

In facultative partial migrants some individuals in a population are migratory and others are resident and individuals decide each year anew which strategy to choose. While the proportion of birds migrating is in part determined by environmental conditions and competitive abilities, the timing of individual departure and behaviours on route are little understood. Individuals encounter different environmental conditions when migrating earlier or later. Based on cost/ benefit considerations we tested whether behaviours on route were affected by time constraints, personality and/or age in a partially migrating population of Blue tits (Cyanistes caeruleus). We captured female Blue tits on migration at the Southern tip of Sweden during early, peak and late migration and measured latency to feed in an unfamiliar environment, exploration of a novel object and hesitation to feed beside a novel object (neophobia). Lean birds and birds with long wings started feeding earlier when released into the cage indicating that foraging decisions were mainly determined by energetic needs (lean and large birds). However, juveniles commenced feeding later with progression of the migratory season in concordance with predictions about personality effects. Furthermore, lean birds started to explore earlier than birds with larger fat reserves again indicating an effect of maintaining threshold energy reserves. Moreover, late migrating juveniles, started to explore earlier than early migrating juveniles possibly due to time constraints to find high-quality foraging patches or a suitable winter home. Finally, neophobia did not change over the migratory season indicating that this behaviour is not compromised by time constraints. The results overall indicate that decisions on route are mainly governed by energetic requirements and current needs to learn about the environment and only to a small extent by differences in personality

Cognition in a changing world: Red-headed Gouldian finches enter spatially unfamiliar habitats more readily than do black-headed birds

Human activities are increasingly confronting animals with unfamiliar environmental conditions. For example, habitat change and loss often lead to habitat fragmentation, which can create barriers of unsuitable and unfamiliar habitat affecting animal movements and survival. When confronted with habitat changes, animals’ cognitive abilities play an important, but often neglected part in dealing with such change. Animals must decide whether to approach and investigate novel habitats (spatial neophilia) or whether to avoid them (spatial neophobia) due to potential danger. For species with strict habitat preferences, such as the Gouldian finch (Erythrura gouldiae), which is an open habitat specialist, understanding these novelty responses may be especially important for predicting responses to habitat changes. The Gouldian finch is a polymorphic species, with primarily red or black head colors, which are linked to differing behavioral phenotypes, including novelty reactions. Here we investigate responses to novel habitats (open, dense) in the Gouldian finch, manipulating the color composition of same-sex pairs. Two experiments, each consisting of novel open and novel dense habitat, tested birds in opposite head color combinations in the two experiments. We measured the number of approaches birds made (demonstrating conflict between approach and avoidance), and their entry latency to novel habitats. Gouldian finches showed more approach attempts (stronger approach-avoidance conflict) towards the dense as compared to the open habitat, confirming their open habitat preferences. Black-headed birds also hesitated longer to enter the dense habitat as compared to the open habitat, particularly in experiment 1, appearing less neophilic than red-headed birds, which showed similar entry latencies into both habitat types. This is surprising as black-headed birds were more neophilic in other contexts. Moreover, there was some indication that pairings including at least one black-headed bird had a stronger approach-avoidance conflict than pairings of pure red-headed birds. Results suggest that the black-headed birds use a cognitive strategy typical for residents, whereas red-headed birds use a cognitive strategy known for migrants/nomads, which may cognitively complement each other. However, as 70% of the population in the wild are black-headed, the spatial wariness we document could be widespread, which may negatively affect population persistence as habitats change

Is vigilance a personality trait? Plasticity is key alongside some contextual consistency

Animals regularly scan their environment for predators and to monitor conspecifics. However, individuals in a group seem to differ in their vigilance linked to age, sex or state with recent links made to personality. The aims of the study were to investigate whether a) individuals differ consistently in their vigilance, b) vigilance is linked to other personality traits and c) other factors affect vigilance in the colour polymorphic Gouldian finch. Birds were tested in same (red-headed or black-headed) or mixed head colour morph same sex pairs in four contexts (novel environment, familiar environment, two changed environments). Vigilance was measured as horizontal head movements. Vigilance showed contextual consistency but no long-term temporal consistency over a year. Head movements were only weakly linked to other personality traits indicative of a risk-reward trade-off with more explorative individuals being less vigilant. Vigilance was highly plastic across situations and affected by group composition. Mixed head colour morph pairs made more head movements, potentially linked to higher social vigilance. Results indicate that vigilance is a highly plastic trait affected by personality rather than a personality trait on its own, which allows adapting vigilance to different situations

Watch out! High vigilance at small waterholes when alone in open trees

An animal’s environment contains many risks causing animals to scan their environment for potential predators and threats from conspecifics. How much time they invest in such vigilance depends on environmental and social factors. Most vigilance studies have been conducted in a foraging context with little known about vigilance in other contexts. Here we investigated vigilance of Gouldian finches at waterholes considering environmental and social factors. Gouldian finches are colour polymorphic with two main head colours in both sexes co-occurring in the same population, black-headed and red-headed. Data collection was done on birds sitting in trees surrounding waterholes by measuring the frequency of head movements, which reflects how frequently they change their field of view, i.e., scan different areas in their environment. A higher frequency generally reflects higher vigilance. Gouldian finches had a higher frequency of head movements when at small waterholes and when sitting in open, leafless trees. Moreover, head movements were higher when birds were alone in the tree as compared to groups of birds. Finally, birds in same head colour morph groups had a higher frequency of head movements than birds in mixed head colour groups. Results indicate heightened vigilance with increased perception of predation risk (small waterholes, open exposed perch, when alone) but that social vigilance also played a role (group composition) with particularly the aggressive red-headed birds being more vigilant when together with other red-headed birds. Future research should investigate the effect of smaller waterholes as global warming will cause smaller waterholes to become more common for longer periods of time, which can increase stress in the birds

The effects of social conformity on Gouldian finch personality

Consistent individual differences in behaviour observed within a population are termed ‘personality’. Studies of personality typically test subjects in isolation, ignoring the potential effects of the social environment, which might restrict the expression of individual behaviour via conformity, or enhance it by facilitation. The Gouldian finch, Erythrura gouldiae, exhibits polymorphism in head colour (red or black) which is related to different personalities: black-headed birds are bolder and less aggressive than red-headed birds. As such, this species provides a unique opportunity to investigate the effects of the presence of a social partner on the expression of individual behaviour. Using two behavioural tests that reflect individual ‘boldness’, exploration of a novel object and time taken to return to feeding following a predator threat, we show that Gouldian finches adjusted their behaviour according to the personality of their partners: where a bird's partner was bolder, it became bolder; where a bird's partner was shyer, it became shyer. This social conformity effect was reduced, however, for black-headed birds paired with red-headed partners in the novel object test; in keeping with previous research findings, bolder individuals were less plastic in their responses. Since variation in personality can promote group cohesion and improve the functioning of social groups in a variety of contexts, we hypothesize that head colour could act as a cue, facilitating preferential associations with those of similar or dissimilar personalities in large mobile flocks of Gouldian finches

Migratory New World blackbirds (icterids) are more neophobic than closely related resident icterids.

Environments undergo short-term and long-term changes due to natural or human-induced events. Animals differ in their ability to cope with such changes which can be related to their ecology. Changes in the environment often elicit avoidance reactions (neophobia) which protect animals from dangerous situations but can also inhibit exploration and familiarization with novel situations and thus, learning about new resources. Studies investigating the relationship between a species' ecology and its neophobia have so far been restricted to comparing only a few species and mainly in captivity. The current study investigated neophobia reactions to experimentally-induced changes in the natural environment of six closely-related blackbird species (Icteridae), including two species represented by two distinct populations. For analyses, neophobic reactions (difference in number of birds feeding and time spent feeding with and without novel objects) were related to several measures of ecological plasticity and the migratory strategy (resident or migratory) of the population. Phylogenetic relationships were incorporated into the analysis. The degree of neophobia was related to migratory strategy with migrants expressing much higher neophobia (fewer birds feeding and for a shorter time with objects present) than residents. Furthermore, neophobia showed a relationship to diet breadth with fewer individuals of diet generalists than specialists returning when objects were present supporting the dangerous niche hypothesis. Residents may have evolved lower neophobia as costs of missing out on opportunities may be higher for residents than migrants as the former are restricted to a smaller area. Lower neophobia allows them approaching changes in the environment (e.g. novel objects) quickly, thereby securing access to resources. Additionally, residents have a greater familiarity with similar situations in the area than migrants and the latter may, therefore, initially stay behind resident species