In spring, the Orange-crowned Warblers (Oreothlypis celata) are frequently seen flitting around in bushes and small trees looking for insects. They can be spotted crossing open meadows as they move from one woodland area to another where willow, alder, and maple are plentiful.
The males arrive each year before the females to establish territory, which they do by signing frequently—a long trill of clear notes—sometimes heard as a single pitch or occasionally with a slight rise in the middle and end. Once a pair is established, females build the nest of dead leaves and other coarse material in the shape of a cup, usually on or near to the ground in an area that has protective vegetation. She lays 3 to 6 eggs that are white or cream-colored and speckled in reddish-brown.
The Orange-crowned is the smallest warbler at 4.5 to 5.5 inches, and is very plain, with yellow-olive coloring. Despite the name, the bird only shows its orange crown when agitated, most often with the males during territorial displays, when they flash their head feathers to expose the patch; otherwise, the orange is rarely seen.