The state bird of Pennsylvania (4), the ruffed grouse (Bonasa umbellus) gets its name from the tufts of black feathers on its neck, which are raised into a ruff by the male during its courtship display (2) (4) (5) (6) (7).
The cryptic colouration of the ruffed grouse is generally mottled grey, brown, buff and black (2) (6) (8). The plumage is lighter and barred on the lower breast and belly (2) (7). Two colour morphs of this species exist: a grey morph and a red morph, with the differences between them being most noticeable on the dorsal parts of the bird, particularly the tail (2) (4) (6) (7) (8).
The grey morph is dominant in the northern parts of the ruffed grouse’s range, while the red morph predominates in the south (2) (5). Intermediates between these are also known to occur (2) (6).
Other key features of the ruffed grouse’s plumage include a short, ragged head crest (2) (4) (5) (7) (8), and a square tail (6), which has a broad, black band towards the tip (2) (5) and can be fanned out (5) (6) (8). The ruffed grouse has feathers that extend from the forehead over the thick, brown, curved bill (6).
As in other grouse species, the legs of the ruffed grouse are also covered in fine, wispy feathers all the way down to the ankle (2) (6) (8), while the grey-blue feet are bare (6). During the autumn, the ruffed grouse grows numerous rows of firm protrusions, called pectinations, along the outside edge of its toes (2) (5) (6) (8). These growths are thought to help the ruffed grouse to walk on snow and cling to icy branches, and are shed in the spring (2) (5) (6).
Both sexes of the ruffed grouse look very similar, and the tail patterning is one of the few ways in which the plumage of the male differs from that of the female (4) (6) (8). The tail band of the female is often broken and the rump feathers each contain a single dot, while the tail band of the male is unbroken and the rump feathers contain more than one white dot each (4) (8). The male ruffed grouse typically has a red or orange eye comb, a coloured patch above the eye, whereas the eye comb is less distinct or absent in the female (2) (8).
The juvenile ruffed grouse looks similar to the female, but does not have the dark band near the tip of the tail and it has a less distinctly marked head (2). Ruffed grouse chicks are tan coloured with dark brown stripes (3).
Twelve subspecies of ruffed grouse are currently recognised, each differing slightly in size, colour and food habits (6).
- Male length: 43 - 50 cm (2)
- Female length: 40 - 47 cm (2)
- Male weight: 500 - 750 g (2)
- Female weight: 450 - 600 g (2)
- Wingspan: 55.9 - 63.5 cm (3)