The ontogenesis of innovative tool use in an American crow (Corvus brachyrhynchos).
Date
2004
Authors
Cole, Patricia D.
Journal Title
Journal ISSN
Volume Title
Publisher
Dalhousie University
Abstract
Description
The genus Corvus (crows, ravens, rooks and jackdaws) is distinguished among avian tool users by the sheer quantity and diversity of their tool use acts. However, almost nothing is known about how these behaviors develop. This six-year study traced tool use ontogenesis in a single American Crow (C. brachyrhynchos) to determine if and to what extent innate behaviors, social, asocial, or insightful learning processes contributed to the development of specific tool use acts. Over the course of the study, Loki spontaneously developed five kinds of tool use involving five different objects. He used a small Frisbee, a water-bottle nozzle, and a plastic cup to acquire and transport water, food, and other objects; he moved a lightweight tripod perch in a way that allowed him to access a previously out of reach item; and he secured a plastic Slinky to his perch and used the free end as a headscratcher. It was found that social learning, in the form of movement imitation, was not a contributing factor in the development of any of Loki's tool use acts. Additionally, the lengthy incubation periods (5--16 months) and incremental behavioural changes that hallmarked the development of Loki's tool use, were inconsistent with insightful, or cognitive, explanations. It is concluded that these complex, innovative, tool use behaviors developed via the modification of species-typical crow behaviors, such as caching, food soaking, and object-directed play, through instrumental learning mechanisms (Thorndikian conditioning, operant conditioning, and skill learning). Finally, contrary to most reports of avian tool use, much of Loki's tool use was not subsistence-oriented. Furthermore, his object-directed play has persevered with familiar items over several years. Thus, it is proposed that, in some instances, object-directed play may qualify as a form of tool use for which the effects are simply less tangible to the casual observer than acts of subsistence-related tool use.
Thesis (Ph.D.)--Dalhousie University (Canada), 2004.
Thesis (Ph.D.)--Dalhousie University (Canada), 2004.
Keywords
Biology, Ecology.