What is "birch partridge"

Ruffed \Ruffed\, a. Furnished with a ruff.

Ruffed grouse (Zo["o]l.), a North American grouse ( Bonasa umbellus) common in the wooded districts of the Northern United States. The male has a ruff of brown or black feathers on each side of the neck, and is noted for the loud drumming sound he makes during the breeding season. Called also tippet grouse, partridge, birch partridge, pheasant, drummer, and white-flesher.

ruffed lemur (Zo["o]l.), a species of lemur ( lemur varius) having a conspicuous ruff on the sides of the head. Its color is varied with black and white. Called also ruffed maucaco.