Western Bluebird

In the middle of the New Mexican desert, I saw an unexpected burst of blue. Western bluebirds, Sialia mexicana, were hopping across the ground at a roadside rest stop. Unlike mountain bluebirds, Western bluebirds do not visit Wyoming, instead preferring to migrate further to the northwest.  Western bluebird males have a darker, royal blue head and a rusty breast compared to the brilliant sky blue of the male mountain bluebirds.

These pretty birds are one of the species declining in numbers due to competition for nest sites from invasive European starlings and house sparrows as well as from logging and other habitat destruction.  Western bluebirds nest in cavities like those made by woodpeckers in dead trees (they cannot make their own cavities with their little bills), so human-provided nest boxes are very important.  They promise to provide good insect control in exchange for a well-situated nest box.