Female Mate Choice, Animal Welfare, and Reproductive Success in Blue‐Gray Tanagers ( <i>Thraupis episcopus</i> ) and Red‐Capped Cardinals ( <i>Paroaria gularis</i> ), at Brookfield Zoo Chicago

Ex-situ breeding programs often utilize pedigree-analysis to select breeding pairs with the goal of maximizing retention of genetic variation and establishing self-sustaining populations. These efforts are limited when selected pairs fail to reproduce successfully. Because mate-choice serves an important role in many mating systems, providing the opportunity to engage in this behavior could lead to greater pair compatibility and offspring survival. In this study, we investigated the impact of female mate-choice on reproductive success and animal welfare of two passerine species: blue-gray tanagers (Thraupis episcopus) and red-capped cardinals (Paroaria gularis). One group of females were allowed to demonstrate a preference between three potential males and were subsequently paired with their preferred mate. A second group of females were paired with their pedigree-assigned partner. We measured a variety of reproductive parameters (onset of nesting, number of eggs, and number of fledglings) and evaluated animal welfare using positive (behavioral diversity) and negative (fecal glucocorticoid metabolite) indicators of welfare. There was no statistically significant difference in reproductive success based on pairing method for either species. Females allowed to choose their mate had significantly higher behavioral diversity than those assigned a mate (p < 0.03), however there was no difference in male behavioral diversity between the two groups. These findings suggest that the opportunity for mate-choice may lead to greater welfare, but only for the individual expressing preference. Outcomes of the study highlight the many variables that can affect reproductive success and the considerable research still needed.