Behavioural factors underlying innovative problem-solving differences in an avian predator from two contrasting habitats.

Innovative behavior is considered one of the main factors facilitating the adaptation of animals to urban life. However, the relationship between urbanization and innovativeness is equivocal, perhaps reflecting aspects of urban environments that influence differently the behavioural traits underlying the occurrence of an innovation. In this work, we analysed the variation in innovative problem-solving performance between urban and rural individuals of the Caracara Chimango (Milvago chimango), with the goal of determining which behavioural trait (or combination) most explained such variation. We found that urban raptors outperformed rural ones in their solving speed and solving level (number of solutions) with a multiaccess box. They also showed more persistence, motor flexibility and diversity, as well as higher effectiveness in their solving attempts than rural chimangos. Sex was not an important factor. Urban chimangos showed less neophobia and spent more time exploring the box than rural birds during the initial habituation period, which probably determined the amount of information about the system that each individual had at the beginning of first problem solving trial. This difference in novelty response both directly and indirectly, through its relationship with persistence, motor flexibility and proportion of effective attempts, explained variability in solving performance. All individuals showed a decrease in solving latency, and an increase in solving level with experience, indicating that learning occurred in both raptor groups. This improvement occurred in parallel with changes in the afore-mentioned traits, though the pattern of improvement differed between urban and rural chimangos. We suggest that the characteristics of urban areas modulate the novelty response of chimangos, along with other correlated non-cognitive behavioural traits, which act in combination to increase the chances that novel problems could be quickly solved, and the resulting new behaviours established in city populations of this species.

Innovative problem-solving in a threatened gull species, the Olrog's Gull (Larus atlanticus).

Innovation, a process that plays an important role in the ecology and evolution of species, is considered an expression of behavioral flexibility in animals. Here we analyzed innovative problem-solving ability and performance enhancement through learning in the Olrog's Gull (Larus atlanticus), under controlled processes and experimental conditions. Trials were undertaken with nine adult individuals captured at a highly urbanized coastal area of Argentina. Each individual was presented with a Plexiglas box that could be opened by pushing or pulling two lids, each lid leading to a separated food reward. We measured problem-solving ability through consumption latency and the number of solved lids. As explanatory variables, we measured contact rate, as a measure of persistence, and the number of effective contacts. The results showed that the contact rate and effective contacts did not affect variables related to problem-solving ability during the first confrontation of the individuals with the closed box. Consumption latency decreased significantly throughout the trials, and with increasing contact rate and effective contacts. The number of solved lids increased through the trials independently of the contact rate and the total effective contacts with the box. Although persistence did not influence individuals' performance during the problem-solving test; this variable affected individuals' ability to solve the task throughout trials. Learning was evidenced by the decrease in the resolution time across experiments, suggesting that successful individuals improved their performance probably through a trial-and-error process. Evaluation of behavioral responses of a threatened seabird to a novel problem-solving task adds knowledge to previous field studies and provides a better understanding of the ability of individuals to adjust their foraging behavior in highly urbanized areas used during the non-breeding season.

Neophobia is negatively related to reversal learning ability in females of a generalist bird of prey, the Chimango Caracara, Milvago chimango.

In an ever-changing environment, the ability to adapt choices to new conditions is essential for daily living and ultimately, for survival. Behavioural flexibility allows animals to maximise survival and reproduction in novel settings by adjusting their behaviour based on specific information and feedback acquired in their current environments. However, a growing body of evidence indicates that an individual's personality type can limit the extent to which the individual might behave flexibly, by influencing the way an individual pays attention to novelty and how much information it collects and stores, which in turn affects the individual's decision-making and learning process. In this study, the behavioural flexibility of a generalist predator, the Chimango Caracara, Milvago chimango, was analysed using the reversal learning paradigm, focusing on the comparison between age classes, and the relation of learning flexibility with a personality trait, the level of neophobia. Due to the low number of male individuals captured, this study was carried out only with female birds. The results showed that age had no significant effect either on the acquisition of a stimulus-reward association, or on the capacity of reversing this previously learned association. Reversal of the response was a harder task for these birds in comparison with the initial acquisition process. The individual's performances in the learning tasks seemed to be uncorrelated with each other, suggesting that they involve different neural mechanisms. Contrary to the general pattern observed in the majority of previous work on personality and cognition in non-human animals, the level of neophobia did not correlate with the initial associative learning performance in both adults and juveniles, yet it showed a significant negative relationship with reversal learning ability, mainly in the regressive phase of this task, for the two age classes. Our results suggest that the predatory and generalist lifestyle of female individuals of M. chimango along with the selective pressures of the environment of the individuals studied might play a critical role in the degree and direction of the linkage between novelty response and learning flexibility observed in this study.

The role of stimulus complexity, age and experience in the expression of exploratory behaviour in the Chimango Caracara, Milvago chimango.

Exploration represents an important way by which organisms evaluate environment information. The decision of whether or not an animal should investigate environmental changes may influence the extent to which animals learn about their surroundings and cope with habitat modifications. We analysed exploration behaviour in a suburban population of a raptor species, the Chimango Caracara, Milvago chimango, by examining how age, previous experience and object complexity influence novel object exploration. Our findings showed that object complexity did not influence caracaras initial approach and contact with objects, but did influence the degree of engagement during exploratory activities, as measured by total exploration time and number of exploration events. These variables were higher for complex objects than for simple objects. Experience resulted in less exploration of simple objects. It is likely that, for caracaras, simple objects are easier to encode and recall than complex objects, so additional exploration of such objects would not provide further information. Results suggest that exploratory behaviour in this raptor was guided more by the benefits of a greater quantity of information obtained by exploring complex objects, than by the risks associated to this activity. We can conclude that caracaras cope with novel features in their surroundings with a novelty-seeking strategy, characteristic for generalist species in discovering early new resources opportunities, and which might be a determining factor for adaptive responses to environment modification.

Inter-individual and age differences in exploration, neophobia and problem-solving ability in a Neotropical raptor (Milvago chimango).

Animal innovations have far-reaching ecological and evolutionary consequences. The occurrence and persistence of an innovation require several processes, including exploration, social and asocial learning, and low neophobia. In addition, the identity of the innovator may determine how these new behaviours are socially transmitted. Taking into account inter-individual and age differences, we investigated three correlates of animal innovation: object exploration, neophobia level and novel problem-solving ability in an opportunistic generalist raptor, the Chimango Caracara (Milvago chimango). Eighteen individuals (7 adults and 11 juveniles) were caught during the non-breeding period and housed in individual cages in outdoor aviaries. Each bird was given three tests: exploration, neophobia and problem-solving. Individuals differed in their response to novel situations both within and between age groups. Most of the juveniles were more explorative and had a lower neophobic response to a strange object than adult birds, but both age groups were able to solve a novel problem when given a food reward. In juveniles, neophobia level and problem-solving performance were inversely related; however, we found no relationship between these behaviours in adults. Exploration did not correlate with neophobia or problem-solving ability for either age group. This research is one of the few studies exploring the inter-individual and age differences in behavioural innovation and their correlates in a bird of prey. The explorative tendency, low neophobia and ability to innovate showed by M. chimango may be advantageous for this generalist and opportunistic raptor and might be some of the factors underlying its ecological success.