Swans are the largest, and generally considered the most beautiful of the waterfowl. The Mute Swan, or scientifically called Cygnus olor, is one of seven species of swan worldwide. A male is known as a cob, a female is a pen, and the young are called cygnets. As the name may suggest, the Mute Swan is normally quiet. However, if you come too close to them or their territory, usually their nests, they may let out a loud warning snort or hiss.
The Mute Swan is only one species out of thousands, perhaps millions, of different birds. All birds, however, must have some of the same traits and characteristics in order to be classified as a bird. Everything with feathers is a bird. Feathers are the unique feature that sets birds apart from all other animals. No other creature possesses feathers. All birds also have a head with a beak.
"Because the habitats and food of birds differ so greatly, a great variety of beak forms developed; some beaks are shaped like spoons or forceps, and others resemble stilettos or curved daggers." (1) The presence of two legs, two wings, and a tail also complete the description of a bird. "An animal with this combination of features you will identify as a bird, even if you have no zoological training at all." (2)
If a bird is able to fly, they cannot become too heavy. It is necessary for the bones of the bird to be both light and tough; light so that the body is not too heavily loaded for flight, and tough, so that they are not easily breakable with the force of landing. The anatomy of the bird must also be 'shock-resistant' in order to withstand the impact of landing, and the skeleton must provide firm attachment...