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Hank Kerschen,
Michael Horejs, Sirisha Manyam
Xavier University
Subject Listing - Biology
Advisor: Dr. George Farnsworth
Thursday, Oral Session 2, Presentation 1, Karpen Hall 112
NUMERICAL DISCRIMINATION IN WILD MOCKINGBIRDS
Previous studies have suggested the presence of numerical discrimination abilities in animals. In one recently conducted experiment, five wild northern mockingbirds (Mimus polyglottos) were presented with a bird feeder that released mealworms (larvae of Tenebrio beetles) as a reward. The mealworms were held on a plank suspended by varying numbers of bamboo sticks which protruded from both sides of the feeder. Upon complete removal of sticks from either end of the feeder, mockingbirds received mealworms. However, if the side with fewer sticks was chosen, then the mealworms were more easily attained. Mockingbirds were found to have the ability to distinguish between one and six sticks and two and five sticks, however failed to distinguish between three and four sticks. To further explore the extent of numerical discrimination abilities in wild mockingbirds, a new experiment was begun using a modified feeder. The new feeder was designed to release mealworms only when approached on the end containing the least number of sticks, thus providing a greater incentive for mockingbirds to discriminate between numbers. This experiment examined the ability of mockingbirds to distinguish between two and five, and three and four sticks. As a control to ensure that the subjects were responding to the number of sticks, three sticks were placed on both sides of the feeder. We hypothesized that wild northern mockingbirds would be able to distinguish between two and five, and three and four sticks by repeatedly selecting the fewer number of sticks in order to receive the mealworm reward. In the control trials, we predicted that subjects would choose either end of the feeder equally.
Advisor: Dr. George Farnsworth, Assistant Professor, Biology, Xavier University, Cincinnati, OH