Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Psychology

Supervisor

Branch, Carrie L.

Abstract

In seasonally variable environments, cognitive abilities help animals adapt to changing conditions. Non-migratory food-caching birds, like black-capped chickadees (Poecile atricapillus), rely on specialized spatial cognition for caching and retrieving food, crucial for winter survival. While spatial cognitive performance in chickadees has been linked to fitness benefits like survival and reproduction, it is unclear how females assess male cognitive abilities. This study examined whether song and plumage serve as indicators of cognitive ability when considering dominance rank. For that, wild male chickadees were tested on tasks assessing spatial learning and memory, cognitive flexibility, and long-term memory retention. In addition, plumage reflectance was measured and fee-bee songs were recorded. Results showed that birds with brighter white plumage and greater black-white plumage contrast performed better on spatial learning and memory tasks, but none of the song variables measured were related to cognitive performance. These results suggest that female chickadees may use secondary sexual traits along with direct observation in mate selection, highlighting the complexity of sexual selection and mate choice.

Summary for Lay Audience

Black-capped chickadees are small songbirds found across the United States and Canada. Unlike many birds, they do not migrate, meaning they must find ways to survive during the winter when food is scarce. One common strategy they use is food-hoarding, which consists of storing food in different locations when resources are abundant and retrieving it later, when food is scarce. To do this successfully, they rely on specialized spatial cognitive abilities, including spatial learning and memory, cognitive flexibility (adapting to changes in the environment), and long-term memory. These cognitive skills are not only crucial for survival but also influence reproductive success. Research has shown that female chickadees may invest more in their offspring when paired with males that have better spatial learning and memory, suggesting that females can recognize ‘smarter’ males, but how do they identify them?

In many bird species, females choose mates based on secondary sexual traits, including variation in feather reflectance and song production. To investigate whether these traits reflect cognitive abilities in chickadees, wild male black-capped chickadees were captured and brought into a controlled environment where they completed three cognitive tests: spatial learning and memory, reversal learning, and long-term memory retention. For the secondary sexual traits, feather reflectance, including brightness and contrast, was measured, as well as the structure of their songs. Variation in the cognitive tasks and secondary sexual traits were then analysed to see if these traits serve as signals of cognitive performance.

Our findings revealed a link between variation in cognition and plumage characteristics: males with brighter white feathers and higher contrast between black and white plumage performed the spatial learning and memory task faster. However, we found no significant relationship between cognitive performance and song characteristics. This suggests that female chickadees may rely more on visual cues, such as plumage brightness, along with direct observation of behaviour, to identify males with better spatial cognitive ability rather than using song as an indicator. These results provide new insights into how cognition and morphology might be connected in animals, highlighting the complex ways in which cognition, survival, and reproductive success are interconnected in nature.

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