How to learn to recognize conspecific brood parasitic offspring

Recognition systems evolve to reduce the risk and costs of making recognition errors. Two sources of recognition error include perceptual error (error arising from inability to discriminate between objects) and template error (error arising from using the wrong recognition template). We focus on how template error shapes host defense against avian brood parasites. Prior experiments in American coots (Fulica americana), a conspecific brood parasite, demonstrated how hosts learn to recognize brood parasitic chicks by using predictable patterns of hatching order of host and parasite eggs. Here, we use these results to quantify the benefit of chick rejection as well as the cost of template error, and we then use mathematical models to explore fitness payoffs of chick recognition from different template acquisition mechanisms. We find that fitness differences between mechanisms do not fully explain aspects of the learning mechanism, such as why coots reacquire their recognition template each...