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In laboratory studies of vocal behavior in animals, subjects are normally isolated in a sound-insulated chamber for recording, but such socially isolated conditions may reduce the chances that they will vocalize. Indeed, past studies using such methods have faced the challenge that subjects remained silent. Knowledge of conditions under which subjects are more likely to vocalize could thus improve experimental design. This study investigated (a) whether kea (Nestor notabilis) could be trained to increase vocal production using operant conditioning and (b) the conditions under which such training was feasible. We found that visual contact with other kea increased the chances that a subject would vocalize spontaneously, therefore making training through positive reinforcement possible. In the conditions where kea could only hear but not see the rest of the group, they were much less likely to vocalize. Subjects were quickly trained to increase vocal production while in visual contact with other kea, and the training remained effective even when visual access later was removed. The procedure described here could be used as a first step in future laboratory studies of vocal behavior, carried out before subjects are isolated, to overcome the challenge of inducing isolated subjects to vocalize. [ABSTRACT FROM AUTHOR]

The ability to forego an immediate reward in favor of a bigger or better one at a later point has been linked with advanced cognitive skills, such as impulse control and forward-planning, and can be assessed by the classic food exchange paradigm. While the ability to perform in such tasks has long been regarded as an exclusive trait of humans and some mammals, that is, primates and dogs, in recent years some bird species have been found to perform similarly as primates. Here we test 10 captive kea (Nestor notabilis), using a food exchange paradigm standardized in earlier experiments, but adding the use of a container to hold the initial item. The subjects reached waiting times of up to 160 s. They also showed significantly different results depending on the difference in the preference level for the presented food items, as well as clearly nonrandom waiting times, displaying forward-planning and economic evaluation of the situation at hand. As in most other species, results were markedly better when exchanging for quality as opposed to quantity. These results provide further evidence for temporal discounting in birds and fit in with the data gained on corvids and parrots in recent years. [ABSTRACT FROM AUTHOR]