Urbanization has greatly affected wildlife and will continue to do so into the future, but we know little about whether traits of closely related species respond similarly to this environmental change. To address this gap, we tested the association between urbanization and morphological traits of two congeneric songbird species-northern cardinals (Cardinalis cardinalis) and pyrrhuloxia (C. sinuatus)-that largely share a niche in and around the Sonoran Desert city of Tucson, Arizona over 137 years. We measured museum and field-collected specimens and used novel hindcast models of urban areas to score urbanization over time. Both urbanization and time of sampling were associated with larger bills in male pyrrhuloxia and in female northern cardinals, which may affect foraging, song, and heat tolerance. Degree of urbanization was also associated with changes in coloration of male northern cardinal face masks and female northern cardinal breast patches. We demonstrate that the effects of urbanization can differ even in two closely related species, with effects on traits involved in visual signaling, heat tolerance, and foraging.