Tiny, but tough, the Verdin is one of the smallest birds in North America. It is gray overall, and adults have a bright yellow head and rusty shoulders. They are adaptable little birds and prefer the harsh low elevation habitats of the Sonoran Desert. They are usually seen singly or in pairs, flitting about actively in the brush, plucking insects from leaf surfaces. Verdins build nests for both breeding and roosting. Because of their small size, heat loss is an issue in the winter and roosting nests help it stay warm. Winter nests have thicker insulation, and may reduce energy requirements for thermoregulation by as much as 50%.