Sol, D., Duncan, R. P., Blackburn, T. M., Cassey, P., & Lefebvre, L. (2005). Big brains, enhanced cognition, and response of birds to novel environments. Proc. Natl. Acad. Sci. U.S.A., 102(15), 5460–5465.
Abstract: The widely held hypothesis that enlarged brains have evolved as an adaptation to cope with novel or altered environmental conditions lacks firm empirical support. Here, we test this hypothesis for a major animal group (birds) by examining whether large-brained species show higher survival than small-brained species when introduced to nonnative locations. Using a global database documenting the outcome of >600 introduction events, we confirm that avian species with larger brains, relative to their body mass, tend to be more successful at establishing themselves in novel environments. Moreover, we provide evidence that larger brains help birds respond to novel conditions by enhancing their innovation propensity rather than indirectly through noncognitive mechanisms. These findings provide strong evidence for the hypothesis that enlarged brains function, and hence may have evolved, to deal with changes in the environment.
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Giraldeau, L. - A., & Lefebvre, L. (1986). Exchangeable producer and scrounger roles in a captive flock of feral pigeons: a case for the skill pool effect. Anim. Behav., 34(3), 797–803.
Abstract: We investigated the foraging producer-scrounger system of a captive flock of feral pigeons (Columba livia) by monitoring the number of food patches each individual produced. In one experiment, three different patch types were tested on the whole flock while, in a second, flock composition was varied for one patch type. In all cases we found non-uniform distributions of the number of patches produced per individual, which suggests the existence of producer and scrounger roles. This result could not be explained by either dominance or variability in individual learning ability. Individuals switched roles in response to changes both in food patch type and flock composition. These results are discussed in light of the skill pool hypothesis, which suggests that, in a group, different foraging specialists will profit by parasitizing each other's food discoveries.
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Lefebvre, L., Whittle, P., Lascaris, E., & Finkelstein, A. (1997). Feeding innovations and forebrain size in birds. Anim. Behav., 53(3), 549–560.
Abstract: The links between ecology, behavioural plasticity and brain size are often tested via the comparative method. Given the problems in interpretating comparative tests of learning and cognition, however, alternative measures of plasticity need to be developed. From the short notes section of nine ornithological journals, two separate, exhaustive data sets have been collated on opportunistic foraging innovations in birds of North America (1973-1993;N=196) and the British Isles (1983-1993;N=126). Both the absolute and relative frequencies (corrected for species number per order) of innovations differ between bird orders in a similar fashion in the two geographical zones. Absolute and relative frequency of innovations per order are also related to two measures of relative forebrain size in the two zones. The study confirms predicted trends linking opportunism, brain size and rate of structural evolution. It also suggests that innovation rate in the field may be a useful measure of behavioural plasticity.
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Ducatez, S., Audet, J. N., & Lefebvre, L. (2013). Independent appearance of an innovative feeding behaviour in Antillean bullfinches. Anim. Cogn., 16(3), 525–529.
Abstract: Behavioural innovations have been largely documented in birds and are thought to provide advantages in changing environments. However, the mechanisms by which behavioural innovations spread remain poorly known. Two major mechanisms are supposed to play a fundamental role: innovation diffusion by social learning and independent appearance of the same innovation in different individuals. Direct evidence for the independent emergence of the same innovation in different individuals is, however, lacking. Here, we show that a highly localized behavioural innovation previously observed in 2000 in Barbados, the opening of sugar packets by Loxigilla barbadensis bullfinches, persisted more than a decade later and had spread to a limited area around the initial site. More importantly, we found that the same innovation appeared independently in other, more distant, locations on the same island. On the island of St-Lucia, 145 km from Barbados, we also found that the sister species of the Barbados bullfinch, the Lesser Antillean bullfinch Loxigilla noctis developed the same innovation independently. Finally, we found that a third species, the Bananaquit Coereba flaveola, exploited the bullfinches’ technical innovation to benefit from this new food source. Overall, our observations provide the first direct evidence of the independent emergence of the same behavioural innovation in different individuals of the same species, but also in different species subjected to similar anthropogenic food availability.
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Giraldeau, L. - A., Lefebvre, L., & Morand-Ferron, J. (2007). Can a restrictive definition lead to biases and tautologies? Behav. Brain Sci., 30(4), 411–412.
Abstract: We argue that the operational definition proposed by Ramsey et al. does not represent a significant improvement for students of innovation, because it is so restrictive that it might actually prevent the testing of hypotheses on the relationships between innovation, ecology, evolution, culture, and intelligence. To avoid tautological thinking, we need to use an operational definition that is taxonomically unbiased and neutral with respect to the hypotheses to be tested.
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Giraldeau, L. - A., & Lefebvre, L. (1987). Scrounging prevents cultural transmission of food-finding behaviour in pigeons. Anim. Behav., 35(2), 387–394.
Abstract: Living in groups should promote the cultural transmission of a novel behaviour because opportunities for observing knowledgeable individuals are likely to be more numerous in this condition. However, in this study pigeons who shared the food discoveries of others (scroungers) did not learn the food-finding technique used by the discoverers (producers). Individually-caged pigeons prevented from scrounging easily learned the technique from a conspecific tutor. When caged pigeons obtained food from the tutor's performance, most naïve observers failed to learn. In a flock, scroungers selectively followed producers. In individual cages, scrounging during the tutor's demonstration was equivalent to getting no demonstration at all. This effect of scrounging did not interfere with subsequent acquisition of the food-finding behaviour when scrounging was no longer possible.
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Seferta, A., Guay, P. - J., Marzinotto, E., & Lefebvre, L. (2001). Learning Differences between Feral Pigeons and Zenaida Doves: The Role of Neophobia and Human Proximity. Ethology, 107, 281–293.
Abstract: Learning differences predicted from ecological variables can be confounded with differences in wariness of novel stimuli (neophobia). Previous work on feral pigeons (Columba livia), as well as on group-feeding and territorial zenaida doves (Zenaida aurita), reported individual and social learning differences predicted from social foraging mode. In the present study, we show that speed of learning a foraging task covaries with neophobia and latency to feed from a familiar dish in the three types of columbids. Pigeons were much faster than either territorial or group-feeding zenaida doves on all tests conducted in captivity, but showed unexpectedly strong neophobia in some urban flocks during field tests. Human proximity strongly affected performance in group-feeding doves both in the field and in captivity. They were slightly faster at learning than their territorial conspecifics in cage tests. In multiple regressions, species identity, but not social foraging mode, significantly predicted individual variation in learning, as did individual variation in neophobia. Wariness of novel stimuli and species differences associated with artificial selection appear to be more important than foraging mode and wariness of humans in accounting for learning differences between these columbids.
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Bouchard, J., Goodyer, W., & Lefebvre, L. (2007). Social learning and innovation are positively correlated in pigeons (Columba livia). Anim. Cogn., 10(2), 259–266.
Abstract: When animals show both frequent innovation and fast social learning, new behaviours can spread more rapidly through populations and potentially increase rates of natural selection and speciation, as proposed by A.C. Wilson in his behavioural drive hypothesis. Comparative work on primates suggests that more innovative species also show more social learning. In this study, we look at intra-specific variation in innovation and social learning in captive wild-caught pigeons. Performances on an innovative problem-solving task and a social learning task are positively correlated in 42 individuals. The correlation remains significant when the effects of neophobia on the two abilities are removed. Neither sex nor dominance rank are associated with performance on the two tasks. Free-flying flocks of urban pigeons are able to solve the innovative food-finding problem used on captive birds, demonstrating it is within the range of their natural capacities. Taken together with the comparative literature, the positive correlation between innovation and social learning suggests that the two abilities are not traded-off.
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Lefebvre, L., Reader, S. M., & Sol, D. (2004). Brains, Innovations and Evolution in Birds and Primates. Brain. Behav. Evol., 63(4), 233–246.
Abstract: Abstract
Several comparative research programs have focusedon the cognitive, life history and ecological traits thataccount for variation in brain size. We review one ofthese programs, a program that uses the reported frequencyof behavioral innovation as an operational measureof cognition. In both birds and primates, innovationrate is positively correlated with the relative size of associationareas in the brain, the hyperstriatum ventrale andneostriatum in birds and the isocortex and striatum inprimates. Innovation rate is also positively correlatedwith the taxonomic distribution of tool use, as well asinterspecific differences in learning. Some features ofcognition have thus evolved in a remarkably similar wayin primates and at least six phyletically-independent avianlineages. In birds, innovation rate is associated withthe ability of species to deal with seasonal changes in theenvironment and to establish themselves in new regions,and it also appears to be related to the rate atwhich lineages diversify. Innovation rate provides a usefultool to quantify inter-taxon differences in cognitionand to test classic hypotheses regarding the evolution ofthe brain.
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Lefebvre, L. (1995). Ecological correlates of social learning: problems and solutions for the comparative method. Behav. Process., 35(1-3), 163–171.
Abstract: Interspecific variation in learning and cognition is often accounted for by adaptive specialization, an ecological framework where variation between species in the environmental problems they face is thought to select for quantitatively and/or qualitatively different abilities. Adaptive specialization theory relies on the comparative method for testing its hypotheses and assumes a naturally selected basis for the predicted differences. This review examines social learning as a specialization to group-living and scramble feeding competition. It points out one important problem with current studies in the area, the lack of quantitative controls for confounding variables that may cause type 1 or 2 error in comparative tests. A linear regression technique is proposed to measure and remove interspecific differences on control tests for which there is no predicted adaptive specialization; as in other areas of comparative biology, the adaptive prediction is then made on the residual deviation from the regression of these confounding variables. Examples are given from research on opportunistic Columbids, the group-living feral pigeon Columbia livia, and the territorial Zenaida dove, Zenaida aurita.
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