Steve Gettle / Eastern Screech Owl (Megascops asio) gray morph, Howell Nature Center, Michigan

Brent Stephenson / Grey morph Dimorphic Egret (Egretta dimorpha) a subspecies of little egret in which there is a white and grey morph. Aldabra Atoll, Seychelles.

Gerrit Vyn / Adult male Gyrfalcon (Falco rusticolus) perched on rocks. This bird is intermediate between a typical gray-morph and a white morph. Seward Peninsula, Alaska, USA, May.

Gerrit Vyn / Eastern Screech-Owl (Otus / Megascops asio) in gray morph plumage, roosting in a Pileated Woodpecker (Dryocopus pileatus) excavation hole in a Red Pine tree, Autumn, Tompkins County, New York, USA

Gerrit Vyn / Common Pauraque (Nyctidromus albicollis) adult, gray morph of the subspecies N. a. merrilli. These birds are often seen perched on dirt roads at night. Starr County, Texas

Jim Brandenburg / Timber Wolf (Canis lupus) black morph peering through foliage, North America

Michael Quinton / Great Gray Owl (Strix nebulosa) in blonde phase perching in tree, Idaho

Steve Gettle / Eastern Screech Owl (Megascops asio) gray morph, Howell Nature Center, Michigan