Phylum Chordata

Subphylum Vertebrata

Class Aves

Body Structure

Feathers are actually dead structures kind of like a nail or hair. The birds cannot replace their own feathers so they have to replace the entire feather. It takes a lot of energy for them to regrow their new feather. The feathers also can support them in their environment and their lifestyle.
Feathers are designed to perfection - they are light and strong, they are flexible and very tough. Feathers do not grow all over the bird, they grow in areas called feather tracks. In between the feather tracks are down feathers. They keep down the body weight and keep the bird warm. Feathers are made of tough and flexible material called keratin. Feathers look solid, but they are not. The spine down the middle, called the shaft, is hollow. The veins are on two halves of the feather. They are made of thousands of branches called barbs. Because there are many space between these barbs, a feather has as much air as matter.
Birds have between 1,000 and 25,000 feathers. Feathers can be divided into 6 categories: contour feathers, semi-plume feathers, down feathers, filoplume feathers, bristle feathers and powder-down feathers.
A bird does not have a heavy jaw bone and teeth, they have a lightweight beak. The shape of a bird's beak varies with the type of food it eats.
All birds have 2 legs and 2 feet. On the ground most birds get around by walking, hopping or climbing. The shape of the feet and legs is different for each type of bird. It is dependent upon use and function. Birds have hollow bones so that it is easier to fly. Also it makes the birds light weight so it easier for them to get of the ground, but some birds don't fly they run or walk.
There is a weight limit for a flapping bird. If an animal is heavy then its wings need to be big, but the bigger the wing, the more muscle it needs. The biggest flying bird is called the Great Bustard. They weigh at the most 32 pounds and 4 feet long. Birds do not have sweat glands but they might cool off in shade or water.

Obtaining Food

As with other bird systems, the digestive system is modified for flight, a beak instead of teeth, a large esophagus to swallow unchewed food, and a muscular gizzard for swallowing and grinding, the food continues through the esophagus into the crop. The crop stores and may begin digesting the food, and passes the food to the stomach. Other species might store their food in their crop. The stomach has two chambers. The gizzard has two sets of obtaining muscles and may contain grit which could be a filter for bones. Birds eat certain food such as earthworms, seeds, mice, frogs, snails, and the most common thing they eat are insects. Some birds also eat nectar from flowers, such as the humming bird.


Most birds look at the color of feathers to determine their mate. Others have dances or will hang upside down. After the birds have chosen their mates they will usually build a nest.Some will build a couple of nests, others will build just one. Birds will lay between one and twenty-five eggs. The larger the population usually means a smaller clutch for birds. If the clutch is laid later in the season it is usually smaller. The further from the equator the bird gets the larger the clutch.


Most birds rely on there wings to travel. Some birds cannot rely on there wings to fly because they cannot fly. Flightless birds rely on their feet to run quickly or swim. Flightless birds that run have very long legs. The ostrich, the largest bird in the world, runs up to 40 mph (65 km/h). Birds that swim rely on their wings not for flight, but for swimming quickly in the water.
Birds that fly rely on their wings to get them airborne. Birds use their wings to push air behind them and make them move forwards in the air. The way their wings are shaped makes the air coming toward them, push up on the bird's wings, allowing the bird to glide in the air.
Most birds fly for breeding,feeding,predator avoidance, and escape. Birds use wings to fly. Birds can run, but they are not fast at all. So, when birds feel dangered, they fly to a place where they think it is safe. That is how they survive. Some birds fly faster than others. Bird of prey have to fly fast to catch their food.


Bird adaptations are often linked to the environment they live in. Vultures are a type of bird called a scavenger. Vultures are not fussy eaters and will eat many kinds of carrion. Other birds, like the finch species that live in the Galapagos Islands, have specific niches. They do not directly compete with the other finch species. Some eat seeds, while others eat insects. Some birds adapt by making their nest in a tree. Some also live areas where most predoters can not get into like a cactus, which is an ideal home for most animals near the bottom of the food chain.
Bird adaptations are linked to what they eat and how they get food. Bird beaks, in particular, reflect the variation not only in the types of foods these animals consume but in where and how they get their food. Some birds, for example, catch their prey in water. Stilts, herons, spoonbills, and oyster catchers wade in shallow water, searching for fish, crustaceans, and mollusks. Stilts and herons have long, pointed beaks to snatch fish they've spotted, while spoonbills move their broad, rounded beaks through the water to catch their prey by feel. As their name implies, oyster catchers eat oysters, clams, and mussels. Their beaks, not surprisingly, are very strong and stiff, enabling them to pry open mollusk shells and extract their contents in a matter of seconds. Birds use a type of sleep called vigilant sleep which allows them to sleep but then also take periodic "peeks". This helps them to keep a weather eye for all incoming predators. Another thing birds do to keep watch and also to keep warm is communal roosting where they roost with other families of birds and trade off watching for the entire nest.

Importance to Humans

All birds are important to humans because they carry seads to other places where new plant life can grow. Birds also provide us with food for our energy. Birds provide food for other animals. So, when those animals get fat and they are ready to be eaten, thats when humans come in and eat them. That is another reason how birds help us to live. Birds also supply us with eggs. Some birds, for example the chicken, produce eggs that us humans can eat! Since birds are highly visible and common animals, humans have had a relationship with them since man has existed. Sometimes, these relationships are mutualistic.


Flightless Birds

There are many types of flightless birds.
Ostrich: Found in Africa, this bird is known for its long neck and legs. Because of its long legs, the ostrich can run up to 40 mph (65 km/h). It is the fastest running bird. It is the largest bird in the world and lays the largest eggs.
Emu: The emu, found in Australia, is the second largest bird in the world. It does not run as fast as its relative, the ostrich, but can run up to 30 mph (50 km/h).
Cassowary: The cassowary is native to the rainforests of New Guinea and Northeastern Australia. Cassowaries are not meat eating birds, but can kill a predator in a life threatening situation. The cassowaries three toed feet have sharp claws that can slice with one kick! This bird can run up to 32 mph (50 km/h) in the dense forests and can jump up to 5 feet (1.5 m)!
Rhea: Rheas are native to South America. Being omnivorous, the rhea prefers broad-leafed plants. They also eat seeds, roots, fruit, insects, and small vertebrates.
Kiwi: Kiwis are located in New Zealand and is the national symbol of New Zealand. Instead of having very long legs to run, the kiwi's special ability is to smell. They have a very keen sence of smell. Kiwi eat small invertebrates, seeds, grubs, varieties of worms, fruit, small crayfish, eels and amphibians.
Penguin: The penguin is found mostly in the southern hemisphere. The penguin does not rely on its feet as the ostrich and emu do. Penguins don't run, they swim. Most penguins feed on krill, fish, squid, and other forms of sealife. They spend half of their life on land and half in the oceans.

Birds of Prey

Birds of prey hunt their food mainly on the wing, using their keen senses especially vision. Their talons and beak tend to be large, and adapted for tearing and piercing skin. Some birds of prey are eagles, kites, true hawks, buzzards, harriers, vultures, falcons, and owls. Some birds of prey are nocturnal, such as the owl.

Perching Bird
Perching birds make up the largest order of birds in the world. There are 59 families and about 5,100 species, which means perching birds are about 60% of all living birds.The perching birds are classified as "Passeriformes," or passerines. The name means "sparrow-shaped". The passerines are also known as songbirds. They are: chipping sparrow, titmouse, wren tit, wren, pipit, waxwing, starling, nuthatch, creeper, bulbul.

Water Birds

Sea Birds-- primarily feeding in open ocean
Wading Birds-- feed by wading in fresh waters
Sea birds eat things such as krill, squid, and fish. Some of them can dive to great lengths to capture food. Those birds can hold their breath for a very long time. Sea birds often migrate after the breeding season. But some don't migrate at all, and stay near the bredding colonies year-round. Water birds are graceful and adept as we watch them gliding, bobbing and diving.