eWestern BirdsThe Quarterly Journal of Western Field Ornithologists
Vol. 31, No. 4
Western Field Ornithologists
Breeding Biology of Lucy's Warbler in Southwestern New Mexico
Scott H. Stoleson, Roland S. Shook, Deborah M. Finch
ABSTRACT: We found Lucy’s Warblers breeding abundantly in mid-elevation broadleaf riparian forests in the lower Gila River valley of southwestern New Mexico. They arrived en masse in the third week of March. Patterns of singing suggested that Lucy’s Warblers might raise two broods. Few were heard or seen after late July. Estimated population densities ranged from 1.7 to 3.3 territories per ha, and Lucy’s Warblers constituted up to 10% of the total bird territories in our study plots. We found 24 nests placed in cavities or behind loose bark. Large cottonwoods and willows were the preferred nesting substrates. Nesting success was high (83%). We found only two nests that had been parasitized by cowbirds but observed five pairs feeding fledgling cowbirds.