Acute exogenous corticosterone treatments have few effects on courtship and pair bonding in zebra finches.

Stress impacts social relationships. In turn, social relationships buffer the stress response in some species. Studies that have investigated the role of corticosterone (CORT) on courtship, mate choice, mating, and pairing have found mixed results. We therefore tested the role of CORT in these steps of the pairing process in the monogamous zebra finch. Male and female zebra finches received either one of 2 doses of corticosterone (CORT, 10 μg and 20 μg, referred to as low and high dose) or a vehicle control (peanut oil). Subjects were then given the opportunity to pair in mixed sex aviaries. Courtship and pair bonding behaviors were observed over 3 days. Overall, zebra finches of both sexes were equally likely to pair or not pair regardless of treatment, although a high dose of CORT increased the latency to form a pair bond. There were no effects of CORT on courtship behavior in either sex, though the low dose increased undirected (non-courtship) singing in males relative to the high dose. Animals treated with CORT, regardless of dose, engaged in fewer copulations than did control animals. When we examined pairing behaviors, we found a decrease in co-nesting in low dose animals. Our results suggest that acute CORT has few effects on pair bonding, suggesting species-specific effects of CORT on behavior.