Watching a bird's posture helps place the bird in a specific group. Examples are horizontal, standing and vertical postures.
Crows, kinglets, vireos and warblers perch with their tails pointing out at an angle.
Robins and other members of the thrush family hold their breasts forward and have an alert, upright posture.
Flycatchers, hawks and owls are some of the birds with a vertical posture. They sit upright with their tails pointing straight down.