Cassin's Vireo are the westernmost "solitary vireo" and they are heading to back to California from their winter grounds in Mexico. The bird breeds in dry forests on mountain's and hillsides. Its nest is cup-shaped and suspends from a hanging tree branch. The male Cassin's Vireo will court the female by presenting his nest building stance. Nests can be made of a variety of materials: grass, feathers, hair, moss, and litter. Click here to watch a video of a nest being built.

(Photo by Peter LaTourrette)