Parental strategies and family life of American coots: Brood parasitism, sibling rivalry, and life history

Life history theory predicts that animals will employ strategies to optimize parental investment. Yet, observed patterns of parental investment often do not seem optimal. Why do avian hosts feed brood parasitic offspring to whom they are not related? Why do parents often fail to compensate for competitive asymmetries among their offspring, even when dominant chicks outcompete their younger siblings? This dissertation describes two extraordinary parental strategies of American coots, which actively mitigate the costs related to selfish offspring.;First, I provide empirical evidence that American coots are able to recognize and reject brood parasitic offspring: a parental strategy rarely observed in other species. Coots accomplish this rare feat even though the parasitism occurs within species, such that host and parasitic offspring are similar in appearance. I then apply the findings of the empirical study to construct and parameterize a model that describes the costs and benefits of this host adaptation. The combination of these two studies presents a unique perspective on the evolutionary dynamics of brood parasites and their hosts.;In the last chapter of this dissertation, I characterize another unique aspect of the coot life history strategy: coots use aggression and favoritism to compensate for the costs of hatching asynchrony while reaping the benefits of brood reduction. My study presents, in unprecedented detail for any avian species, the suite of parental strategies that optimize brood size and balance the tradeoffs between chick number and quality. This work expands our view of the limits of avian life history.