 In fall, they start to move south around early October, and by mid-November, only the last stragglers still remain up North.Geographic variation in the "iliaca" complex is minor compared to individual variation, both in morphology and molecular data samples.The western Yukon fox sparrow (Passerella iliaca zaboria) differs from the nominate subspecies, the eastern fox sparrow (Passerella iliaca iliaca) only in having a grayer head and browner malar stripe on average.