2 Cowbird as a Model System for Studying the Development and Evolution of Nestling Begging Displays 9 . 2 . 1 The Influence of Proximate Factors on Cowbird Begging

Although the brown-headed cowbird (Molothrus ater) is the most intensively studied brood parasite in the world, much of the research on cowbirds has focused on the negative effects of parasitism. Here, we argue that negative attitudes toward the cowbird have overshadowed opportunities this species provides for advancing our understanding of social behavior, physiology, evolution, and ecology and conservation of birds. Cowbirds are widely distributed, amenable to captive study, and easy to study in areas where they are abundant. Cowbird nestlings must communicate to unrelated host parents, but unlike some parasitic nestlings, they have no specialized adaptations for doing so. In some areas they often share nests with relatives, which may influence the degree of virulence host experience. The generalist strategy of the cowbird can be used to answer questions about the impact of high reproductive output on female cowbirds, maternal allocation of resources into eggs, and the consequences of exposure to a range of pathogens while visiting host nests. Cowbirds and their hosts provide a contrast to cuckoo-host systems because they are at an earlier stage of B. D. Peer (*) Department of Biological Sciences, Western Illinois University, Moline, IL, USA e-mail: BD-Peer@wiu.edu J. W. Rivers Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, USA L. Merrill Illinois Natural History Survey, Prairie Research Institute, University of Illinois, Champaign, IL, USA S. K. Robinson Florida Museum of Natural History, Gainesville, FL, USA S. I. Rothstein Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, USA # Springer International Publishing AG, part of Springer Nature 2017 M. Soler (ed.), Avian Brood Parasitism, Fascinating Life Sciences, https://doi.org/10.1007/978-3-319-73138-4_9 161