Grey-headed woodpecker Concern" rating is primarily based on the large distribution of the species. The grey-headed woodpecker is long and weighs . Specimens of the more widespread of the two Eastern subspecies, "P. c. jessoensis", are usually a little larger and heavier than individuals from the type locality. On average, it is somewhat smaller and lighter than the European green woodpecker. In the field, this distinction in size is difficult to make. Its size is approximately that of a Eurasian collared dove. Grey-headed woodpeckers have uniformly olive green upperparts, transitioning across the neck to a light grey, the head being that latter
Imperial woodpecker Imperial woodpecker The imperial woodpecker ("Campephilus imperialis") is a species of bird, a member of the woodpecker family Picidae. The genus "Campephilus" is essentially a tropical one, embracing 13 species, including the imperial woodpecker. If it is not extinct, it is the world's largest woodpecker species, at long. Researchers have discovered that the imperial woodpecker has slow climbing strides and a fast wing-flap rate compared with other woodpeckers. Owing to its close taxonomic relationship, and a similarity in appearance, to the ivory-billed woodpecker, it is sometimes called the "Mexican ivorybill", but this name is also used for the pale-billed woodpecker.