Grouse - Reproduction

Reproduction

In all but one species (the Willow Ptarmigan), males are polygamous. Many species have elaborate courtship displays on the ground at dawn and dusk, which in some are given in leks. The displays feature males' bright-colored combs and in some species, bright-colored inflatable sacs on the sides of their necks. The males display their plumage, give vocalizations that vary widely between species, and may engage in other activities such as drumming or fluttering their wings, rattling their tails, and making display flights. Occasionally males fight.

The nest is a shallow depressions on the ground, often in cover, with a scanty lining of plant material. The female lays one clutch, but may replace it if the eggs are lost. She begins to lay about a week after mating and lays one egg every day or two; the clutch comprises 5 to 12 eggs. The eggs have the shape of hen's eggs and are pale yellow, sparsely spotted with brown. On laying the second-last or last egg, the female starts 21 to 28 days of incubation. Chicks hatch in dense yellow-brown down and leave the nest immediately. They soon develop feathers and can fly a little before they are two weeks old. The female (and the male in the Willow Grouse) stays with them and protects them till their first autumn, by which time they reach their mature weight (except in the male capercaillies). They are sexually mature the following spring but often do not mate until later years.