Master of Science
Traditionally, dominant animals have been regarded as better competitors in all aspects of life, including cognition. However, the survival and reproductive advantages of being a dominant chickadee are surprisingly modest. It is possible that subordinate individuals compensate for the disadvantages of a lower rank with better cognitive abilities. If dominants are monopolizing prime food sources, subordinates may have developed better associative learning skills by learning to associate novel types of stimuli with food rewards. In this thesis, I asked whether dominance rank is correlated with cognitive ability in Black-capped Chickadees. I determined dominance rank in six flocks of six chickadees, and then tested each bird individually on two different associative learning tasks. I used artificial trees with holes that held food reward in both tasks. The first task was a colour associative learning task, in which birds learned that only holes marked with a specific colour contained a food reward. The second task was a spatial associative learning task, in which birds learned that only holes in specific locations contained a food reward. There were no differences in associative learning or spatial memory between dominant and subordinate birds, showing no support for the hypothesis that there are differences in learning and memory between chickadees of different dominance ranks.
Summary for Lay Audience
Traditionally, we think of dominant animals as the ones who have the best territories, the most successful offspring, and the best chances of survival. However, evidence suggests that the advantages of being dominant have been exaggerated and that lifetime reproductive success does not differ much between dominant and subordinate animals. This may be because subordinate animals have better learning and memory abilities to make up for the disadvantages of low rank. I gave black-capped chickadees two learning tasks to see if subordinate birds had better learning and memory than dominant birds. In both tasks, birds were presented with trees that had holes drilled into them. Some holes contained sunflower seeds, while others did not. In the first task, birds learned that only holes marked with a specific colour contained sunflower seeds, and in the second task, birds learned that only holes in specific locations contained sunflower seeds. Both dominant and subordinate birds showed equal performance on both learning tasks, showing that learning and memory ability does not differ between chickadees of different rank.
Cho, Gloria Hyun Young, "Is Social Rank Correlated With Cognitive Ability in Black-capped Chickadees?" (2020). Electronic Thesis and Dissertation Repository. 7338.
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