Birds

Birds-

Birds are a class of the chordates or vertebrate phylum. They are similar to other chordates in that they have a backbone. They are unique in the fact that they are covered with feathers and fly. There are four types of feathers for birds:

• Down Feathers - These keep both young and old birds warm. They are soft.
• Filoplumes - These are thin and hairlike with tufts on the end.
• Contour Feathers - These cover and protect the body and give the bird its color. The color of these feathers can depend on whether the bird is the male or female of the species.
• Quill Feathers - These large, strong feathers are in the wings and tail and help the bird with flying.

There are about 9000 species of birds, with 24 orders and 146 families. Scientists believe that birds evolved from reptiles and dinosaurs.

Birds are found throughout the world, from the tropics to polar regions. One unique characteristic of many birds is their tendency to migrate. This means that the birds move from colder to warmer areas as the winter approaches.

Birds can be both helpful and harmful to man. They are helpful as they frequently eat harmful insects. They provide food for man. They are pets and can be very decorative. They are harmful when they eat crops and kill animals.

Eagles
The bald eagle is 30-31 inches in length with a wingspan of 6-7 feet. It has a dark brown body, a white tail and a white head and shoulders. It has bright yellow eyes, a large hooked yellow bill, and powerful yellow legs and talons. Young bald eagles won't have a white head and shoulders until they are about five years old. Males and females look alike, although the female is a little larger.



Ducks
Duck is the common name for a number of species in the Anatidae family of birds. The ducks are divided between several subfamilies listed in full in the Anatidae article; they do not represent a monophyletic group but a form taxon, being the Anatidae not considered swans and geese. Ducks are mostly aquatic birds, mostly smaller than the swans and geese, and may be found in both fresh water and sea water. The overall body plan of ducks is elongated and broad, and the ducks are also relatively long-necked, butnot as long-necked as the geese and swans. The body shape of diving ducks varies somewhat from this in being more rounded. The bill is usually broad and contains serrated lamellae which are particularly well defined in the filter-feeding species. In the case of some fishing species the bill is long and strongly serrated. The scaled legs are strong and well developed, and generally set far back on the body, more so in the highly aquatic species. The wings are very strong and are generally short and pointed, and the flight of ducks requires fast continuous strokes, requiring in turn strong wing muscles. Three species of steamer duck are almost flightless however. Many species of duck are temporarily flightless while moulting; they seek out protected habitat with good food supplies during this period. This moult typically precedes migration.

Emu

The emu is a flightless bird called ratites, meaning it has a flat breastbone. Ratites differ from other birds in the lack of a keel, a breast bone to which flight muscles are attached. The animals also lack the "preen gland" — so that the feathers are dry and not oily. General characteristics of flightless birds include large legs and feet well developed for running, small wings, and soft feathers not suited for flight. In the emu, the main and secondary feather shafts are of equal length, so that every feather appears to be double. The feathers feel almost like "hair." The emu is a ratite of Australia second in size among living birds only to Africa's ostrich. Emus are capable of running up to 30 m.p.h. when alarmed or threatened. They are adept at swimming and may stand six feet in height and weigh up to 120 pounds. They are often quite tame and approachable when left unmolested.