Birdshot is a type of metal shot which is designed to be used in shotgun shells. It consists of spheres of metal milled to be the same size so that they can be packed together into a shell. When the shell is fired, it separates, allowing the birdshot to fly out at the intended target. Classically, birdshot is made from lead, although shot from steel, tungsten, and other materials has become more popular due to environmental concerns about lead.
This style of shot is thusly named because it is designed for use in hunting game birds. Larger shot is known as “buckshot,” in a reference to the fact that it can be used to hunt deer, pigs, and larger game. The shot is packed into a cartridge backed with padding and gunpowder for the purpose of being loaded into a weapon and fired.
The varying sizes of birdshot are customized, as you might imagine, for game of different sizes. The hunter's goal is to be able to fire from a reasonable distance and achieve enough penetration with the shot to kill or at least stop an animal. If shot which is too large is used, it can cause severe damage, making the game worthless for the table or trophy room. Shot which is too small can inflict injuries, but it will not be effective enough to actually kill the animal. In addition to being inefficient, small shot can also be inhumane, as the bird may suffer considerably as a result of the birdshot injury.
Although birdshot is designed for birds, it can certainly injure larger animals, as American Vice-President Dick Cheney proved in 2006 when he accidentally shot a fellow hunter while the men were pursuing quail. Although Cheney's victim was not severely injured, the condition did cause pain and later medical complications due to a migrating piece of shot which interfered with his heart. Birdshot has also been historically used as a deterrent to poachers and trespassers by landowners.
Many hunting supply stores sell birdshot, or shotgun pellets which are packed with birdshot to be ready for use. As with any type of ammunition, it is important to understand the appropriate uses for birdshot before using it, and you should always practice basic firearms safety when working with munitions and guns. As a general rule of thumb, do not aim a gun anything you do not want to shoot, as even lightweight ammunition can cause eye and face injuries.