Can you teach an old parrot new tricks? Cognitive development in wild kaka (Nestor meridionalis)

Abstract

Despite recent efforts to characterize innovative individuals within a species, we still know very little about the ontogeny of innovation ability. A number of studies have found that innovation rates are correlated with personality traits, such as neophilia and exploration. Juvenile birds are frequently more neophilic and explorative, yet few studies have found evidence of age-related differences in innovative problem-solving success. Here, we show consistently higher innovation efficiency in juveniles of a wild, omnivorous parrot species across a variety of tasks and contexts. We tested 104 kaka (Nestor meridionalis), ranging in age from four months to 13 years. Twenty-four individuals participated in all three of our problem-solving tasks, two of which involved a familiar feeder and one an entirely novel apparatus. Juveniles were the most efficient problem-solvers in all three tasks. By contrast, the adults' success was context dependent and limited to the novel apparatus, which did not require modification of a pre-learned behavioural response. This suggests greater behavioural flexibility in the juvenile birds, who also showed higher persistence and exploratory diversity than adults. These traits may enable young kaka to discover efficient foraging techniques, which are then maintained throughout adulthood.

Keywords: Nestor; age differences; exploration; innovation; parrot; problem-solving.

Figure 1.

(a) A kaka using the feeders at Zealandia. (b) The set-up in the block-removal task. (c) A kaka removing the block. (d) A kaka opening the lid in experiment 2. (e) A kaka succeeding in the string-pulling task. (Online version in colour.)

Figure 2.

Mean proportion of successful trials ± s.e. for each experiment and age group for the 24 individuals that participated in all three tasks. (Online version in colour.)

Figure 3.

Mean ± s.e. (a) time spent per trial (individual persistence) and (b) proportion of exploratory behaviours for the different age groups as well as solvers and non-solvers. Data are shown for all individuals for whom these measures could be scored (n is given at the base of the bars). (Online version in colour.)