Pre-exposure effect in social foraging: A study with groups of pigeons (Columba livia)

In collective foraging situations, the members of a group use two different kinds of responses to obtain food: producing and/or scrounging. Previous studies indicate that the frequency of use of both responses depends on the conditions to which the members of the group have been previously exposed to, which shows the importance of studying learning factors specifically. The aim of this study was to assess the effect of pre-training under different foraging conditions with the strategies used in collective foraging. Six groups of pigeons were assessed, with three pigeons per group. Three of these groups received a pre-exposure under individual conditions in which they engaged in production responses to have access to food; the other three groups were pre-exposed under collective conditions in which they were able to have access to food by producing or scrounging with a mixed strategy. The groups under both conditions were subsequently assessed during three collective foraging sessions in equal conditions. The assessed indicators were: the producer-scrounger response rate; the percentage of exploited patches and the time between opening of patches; the results showed that the pre-exposed groups under individual conditions used the production response more frequently compared to scrounging. When performing a correlation between the percentage of patches opened and the percentage of individuals that opened one patch at least, a high and positive rate was obtained between both variables. In summary, the findings in this paper show the impact of learning in collective foraging situations.