Feathered Lectures-Evidence of Perceptual Factors on Social Learning in Kea Parrots (Nestor notabilis)

Abstract

Social learning describes the acquisition of knowledge through observation of other individuals, and it is fundamental for the development of culture and traditions within human groups. Although previous studies suggest that Kea (Nestor notabilis) benefit from social learning, experimental evidence has been inconclusive, as in a recent two-action task, all perceptual factors were ignored. The present study attempts to address this by investigating social learning in Kea with a focus on social enhancement processes. In an experiment with a captive group of Kea, we investigated whether individuals that had the opportunity to observe a conspecific performing a simple task subsequently show better performance in that task than a control group without prior demonstration. This study provides a strong tendency of greater success in skill acquisition in Kea as a result of social learning. Kea that observed a conspecific solving a task showed clear evidence of perceptual factors drawing attention to the relevant parts of the experimental apparatus and manipulated these significantly more (100% of trials) than control birds (77.8% of trials). Combined with a strong trend (p = 0.056) of the test subjects solving the task more than the control subjects, this shows conclusively that Kea, at least when required to solve a task, do attend to perceptual factors of a demonstrated action.

Keywords: avian cognition; parrot behavior; parrot cognition; stimulus enhancement.

Figure 1

Kea aviary at Haidlhof Research Station. (a) Main aviary with hanging branches, ponds, shelter structures and feeding tables. (b) Schematic plan of the aviary.

Figure 2

Schematic of experimental compartment.

Figure 3

Test apparatus. (a) Schematic of apparatus with two differently colored strings on each side of the test box and a tube that released the reward into the feeding tray in front of it. (b) Kea manipulating the test box. The board on top was necessary to prevent the Kea from manipulating the top of the box or the strings from a position other than standing on the ground.

Figure 4

Schematic of social learning tests. (a) Demonstration phase, where the test subject is located in the observation compartment while the demonstrator solves the task in the test compartment. A sliding wire-mesh door separates the two compartments while allowing the observer to see the demonstration. (b) Test phase, where the demonstrator is gone and the test subject is allowed access to the box for 2 min or until it solves the task, whichever comes first. Functional (red) and non-functional (blue) strings shown.

Figure 5

Schematic of control group tests. (a) The control subject is given two minutes to observe the box without having access to it. The subject can see the apparatus through the wire-mesh door. (b) Test phase, where the control subject is allowed into the test compartment and has a maximum of two minutes to solve the box through trial and error.

Figure 6

Photographs of the experimental box. (a) Side view of the box showing the functional (red) string attached to a lever and threaded through a pulley. When this string is pulled, a small piece of peanut is released into the reward tray at the bottom. (b) Top view of box with open lid. By pulling the string, a lever moves and turns the hopper to release a peanut. Only the red string on the right is functional. The blue string is attached to a dummy lever and is non-functional.

Figure 7

This figure shows the mean number of sessions where the subject was successful in solving the task, organized into control and test groups. The control group was successful in 14% of sessions (5/36), and the test group was successful in 44% of sessions (16/36). There was a non-significant trend towards the test groups being more successful (p = 0.056).

Figure 8

This figure shows each individual subject’s success over all three trials (test or control), organized by whether that subject had past experience with string-pulling. More experienced subjects were successful in solving the task, but not all experienced subjects managed. One inexperienced subject in the test group, Di, solved the task, whereas no inexperienced subjects in the controls group solved the task.

Figure 9

This figure shows the mean proportion of time that the subjects spent manipulating the correct string during a trial, compared to the total string manipulation time, organized into control and test groups. The control group manipulated the correct string in a proportion of 0.51 of the time, and the test group manipulated the correct string significantly more, in a proportion of 0.67 of the time (* p = 0.029).