Shuttlecock

A shuttlecock (often abbreviated to shuttle and also - improperly - known as a bird or birdie) is a high-drag projectile, with an open conical shape: the cone is formed from sixteen overlapping goose feathers embedded into a rounded cork base. The cork is covered with thin leather or synthetic material.

Shuttles with a plastic or nylon skirt are often used by recreational players to reduce their costs as feathered shuttles break easily. These nylon shuttles may be produced with a cork made of a hard sponge instead of natural cork.

Additionally, nylon shuttlecocks come in three varieties, each variety for a different range of temperatures. These three varieties are known as green (slow speed), blue (middle speed), and red (fast speed). The colors, and therefore speeds, are indicated by colored strips fastened around the cork. In colder temperatures, a slower shuttle is used, and in hotter climates, a faster one is chosen.

www.wikipedia.org