Mountain quail (Oreortyx pictus) breeding biology is poorly understood in part because sexes of birds cannot be readily identified. We demonstrated that presence or absence of high-molecular-weight microsatellite DNA of the repeated sequence thymine-cytosine-cytosine ([TCC] n ) accurately indicates mountain quail gender. Genetic methods correctly identified the sex of all 18 (12 F, 6 M) mountain quail tested. Additionally, for 30 of 31 captive mountain quail, we evaluated such morphological characteristics as plumage color of the neck, hypothesized to be associated with mountain quail gender. No single morphological characteristic (i.e., wing, tarsus, claw, and head plume length, body mass, and head width) consistently indicated gender. Despite controlling for age, stage of molt, and environmental factors among captive quail, presence or absence of olive feathers on key areas of the neck and upper breast failed to indicate gender for individuals within each sex. Three of 18 females resembled males in lacking olive feathers laterally on the upper neck. Three of 12 males resembled females in exhibiting olive feathers laterally on the lower neck. Using presence of olive feathers at the junction of pectoral and sternal feather tracts as a female-specific characteristic incorrectly indicated the gender of 3 of 30 (10.0%) quail (1 F, 2 M).