The blackcock is the male of the black grouse, a bird native to moorland and heath in parts of northern Europe and Britain. In poetry, “blackcock feather” often refers not simply to the bird but to the dark plume worn in Highland dress, especially on a tartan bonnet. The image can suggest Scottish identity, ceremony, military-style pageantry, or the rugged landscape of heather and hills.

“Blackcock” is a compound noun: “black” + “cock,” with “cock” meaning a male bird. The female black grouse is called a greyhen. The black grouse is known for the male’s dark plumage, distinctive lyre-shaped tail, and dramatic spring courtship displays, often called lekking. In Scottish dress, a blackcock feather may be associated with a bonnet or cap; in this context, it is an item of costume rather than a live bird. Do not confuse blackcock with a generic black bird. It names a particular species, the male black grouse. Related terms include black grouse, grouse, greyhen, tartan, bonnet, and Highland dress.