I n their recent paper “In Pursuit of Mobile Prey,” Bird et al. (2009) find no relationship between body size and return rates among prey taken by Martu hunters in western Australia. They attribute this trend to an often overlooked correlation between body size and mobility: larger animals are often highly mobile, which leads to frequent hunting failure. When the authors ac- count for the costs of these failures, their estimates of post-encounter return rates for large animals drop substantially and become uncorrelated with body size. This phenomenon, which the authors suggest may be quite common, has clear implications for archaeological applications of foraging models that assume body size and on-encounter returns are positively correlated and is also at odds with a great deal of experimental and ethnographic observation (as discussed by Broughton et al. 2010). The Martu pattern also depends strongly on the manner in which returns were calculated, and it is worth considering both the validity of the method and the generality of the results. We take this opportunity to outline what we perceive as problems with Bird et al.’s approach, to point out areas in which we are in agreement their position, and to suggest what we see as more productive ways to approach the application of evolutionary theory to questions of provisioning and the trade- offs between immediate returns and future bene- fits derived from social interaction and obliga- tions. Key to Bird et al.’s argument is their charge of pursuit time to specific prey types beginning with a forager’s observation of tracks or other sign. Whether tracking is incorporated as handling time is important because it drives subsequent pat- terns and arguments about body size and return On Prey MObility, Prey rAnk, And FOrAging gOAlS Andrew Ugan and Steven Simms In their recent paper “In Pursuit of Mobile Prey”, Bird, Bliege-Bird, and Codding (2009) identify a negative relationship between body size and post-encounter returns among Martu prey in western Australia, attributing the phenomena to the greater mobility of large animals and associated risk of hunting failure. While this phenomenon has implications for archae- ological applications of foraging models that assume body size and on-encounter returns are positively correlated, the Martu data may be less exceptional than they appear. Here we outline the reasons for our skepticism, point out areas in which we are in agreement, and build upon their findings by exploring the trade-offs between foraging to maximize efficiency and immediate returns and foraging for purposes other than immediate provisioning. En su reciente artículo “On the Pursuit of Mobile Prey”, Bird, Bliege-Bird, y Codding (2009) identifican una relación entre el tamaño y la tasa de rendimiento post-encuentro de la presa de los Martu en el oeste de Australia, y atribuyen el fenómeno al mayor movilidad de animales grandes y el riesgo asociado de no matarlas. Aunque esto fenómeno tiene implicaciones por las aplicaciones de modelos de forrajear que asumen que el tamaño del cuerpo y la tasa de rendimiento son positivamente correlacionados, los datos del Martu pueden ser menos excepcional que parecen. Aquí presentamos las razones por nuestras dudas, indicamos áreas en que estamos de acuerdo con la posición de Bird et al., y aprovechamos sus resultados para discu- tir los compromisos entre forrajear para maximizar eficiencia y retornos inmediatos y forrajear para propuestos además de abastecimiento inmediato. Andrew Ugan  Departamento de Antropología, Museo de Historia Natural, Parque Moriano Moreno, (5600) San Rafael, Mendoza, Argentina Steven Simms  Department of Sociology, Social Work, and Anthropology, Utah State University, Logan, Utah 84322 (s.simms@usu.edu) American Antiquity 77(1), 2012, pp. 179–185 Copyright ©2012 by the Society for American Archaeology 179 AQ77(1)Ugan_Layout 1 1/9/12 4:55 PM Page 179