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Both adaptive and neutral trait evolution can contribute to divergence, but the relative contributions of the two remain unclear. Oviposition preference, a trait that has been demonstrated to contribute to divergence among populations, is often presumed to be an adaptive trait. Few studies explicitly test this assumption, however, and several researchers have demonstrated non-adaptive oviposition preferences in wildlife populations. In this study, we test whether adaptive divergence can explain current differences in the oviposition preferences of two sister species. In 2012 and 2013, we conducted a demographic study of sympatrically breeding populations of two sparrow species (Ammodramus caudacutus and Ammodramus nelsoni) and measured vegetation characteristics at nest and non-nest points. We found evidence for oviposition preference in both species and significant differences between the species' preferences. The vegetation characteristics that vary between species did not predict nest survival or offspring production, however. Our results provide an example of oviposition preference at a population level that appears non-adaptive as measured by productivity. We discuss other mechanisms by which oviposition preference can be adaptive, and make a case for the role of neutral evolution in shaping the oviposition preferences of these species. If divergence in oviposition preference is at least periodically neutral, as we hypothesize, such differences could provide fodder for future adaptation or reproductive isolation among populations.