We conducted a comparative study of 2 closely related and sympatric species, Northern Bobwhite (Colinus virginianus) and Scaled Quail (Callipepla squamata), to explore the drivers of interspecific variation in alternative reproductive strategies. Specifically, we used parentage analyses to determine rates of extrapair paternity and intraspecific brood parasitism for each species, and evaluated possible mechanisms for explaining variation in these rates between the 2 species. During 2013–2014, we genotyped hatched (n = 388 for Northern Bobwhite and n = 214 for Scaled Quail) and unhatched (n = 32 for Northern Bobwhite and n = 9 for Scaled Quail) eggshells from 34 Northern Bobwhite and 22 Scaled Quail nests in western Oklahoma, USA. Extrapair paternity occurred in 85% of Northern Bobwhite nests and 9% of Scaled Quail nests. The number of sires for each nest was greater in Northern Bobwhite nests (x̄ = 2.29 ± 0.14 SE sires per nest) than in Scaled Quail nests (x̄ = 1.09 ± 0.06 sires per nest). Intraspecific brood parasitism rates varied considerably between Northern Bobwhite (21%) and Scaled Quail (0%). Northern Bobwhites also parasitized Scaled Quail nests. Variation in extrapair paternity and intraspecific brood parasitism rates between the Northern Bobwhite and Scaled Quail appeared to be related to differences in their life history strategies (r-selected vs. K-selected strategy) as well as differences in breeding population densities.