The role of intervening variables in learning differences between group-foraging and territorial columbids /

Previous work on feral pigeons (Columba livia) and zenaida doves (Zenaida aurita) suggests that both individual and social learning varies with type of competition: rapid non-aggressive feeding is associated with rapid individual learning as well as rapid social learning from the tutor types a bird usually feeds with in the field. Comparative learning tests, however, may be influenced by intervening variables like neophobia and tameness: tests are always run on captive animals by human experimenters using novel stimuli.This thesis compares pigeons to territorial and group-feeding zenaida doves on their response to novel stimuli in the field and in captivity, in the presence or absence of humans. In single cages, tameness and neophobia co-vary with learning: pigeons are more rapid than doves at learning, at interacting with a novel apparatus and at feeding in the absence of the human; territorial zenaida doves are slower than group-feeding doves on all three tests. Multiple regressions show that neophobia and tameness explain an important part of the variance in learning. These results are confirmed by a re-analysis of data previously obtained on finches (Whittle, 1996), where neophobia predicts individual learning which in turn predicts social learning.In the field, however, neophobia has opposite effects: territorial zenaida doves now show the smallest effect of novel stimuli on feeding latency. Experiments that test evolutionary predictions about learning using captive animals are thus open to questions of internal and external validity: when we measure comparative performance on a captive learning test, is it really learning we are measuring and does it mirror, as it should, adjustment to environmental novelty in the field