--> Aerodynamics of Animals ...Birds & Bats

Introduction

We love to watch birds. They fly! From the very start of time we have been
looking at them. They do such great things.

Birds take off

Birds soar and dive

Birds twist and turn in the air

Birds land without help on the ground

It has taken man a long, long time to learn about flight. We first tried to
do what a bird can do. But we could not.

We had to make a special engine that could move man through the air. The
engine had to be powerful but light. We had to be able to fly in a controlled
way.

A bird is a wonder. It is a natural flying machine. What is it about a bird?

Everything about a bird is made for flight. We need to look at the parts of a
bird. We also need to look at how birds take off, fly and land.

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What Makes a Bird a Bird?

Birds are very special. Birds have feathers. Birds live in a hurry.

Birds are fast. They breathe faster than any other animals. Their heart
beats faster. Their body temperature is higher. Birds lay eggs. All birds
have wings. But not all birds fly.

Birds play a big role in the balance of nature. Some birds eat seeds.
Because of this lots and lots of weeds do not grow on the earth.

We eat eggs from birds. We make pillows and quilts from bird feathers.

We see birds as symbols. The dove for peace. The owl for wisdom.

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Physical Characteristics of a Bird

Looking at a bird is fun. There are many things that make a bird a bird.

Feathers

The first thing we see is a bird's feathers. Feathers make birds special.
They are strong and tough. But the feathers are light and move easily.

Feathers do not grow all over a bird. They grow on "feather tracks".
In between the feather tracks down feathers grow.
Birds need their feathers. A bird takes time to clean them. Birds have lotsof feathers. When they wear out new feathers grow.
Feathers keep the bird
warm.


The shape of the wing helps the bird to fly. The shape is made by the
feathers. The tail of the bird is like a rudder. It helps the bird steer.
When the bird lands the tail is used as a brake.

Beaks and Feet

The beak of a bird is special. Other animals have a jaw and teeth. Birds get
their food with their beak only. Some beaks are long and pointed to spear
fish.

All birds have 2 legs and 2 feet. On the ground the birds walk, hop or climb.
Birds with short legs mostly fly. All birds have claws on their toes.

Internal Structures of a Bird

The insides of a bird are made for the most power and the lightest weight.
The biggest flying bird today is the Great Bustard. They weigh 32 pounds and
are 4 feet long.

But most birds are smaller. This is the best way to fly. Another way is to
use light weight `stuff' to make the bird.

Feathers are light. Birds have less bones. The bones they have are hard but
thin. Some birds have bones weighing less than their feathers.

Birds have less muscle. Their bones are "glued" together . This keeps them
lighter too.

The biggest muscles a bird needs are its flight muscles. These muscles need
to raise the entire body weight into the air.

The eyes of the bird are very strong. Their hearing is also.

Internal Power System

Birds have a natural machine. It helps them with power in lift and take-off.
The inside organs of a bird run at high speed. They need to eat "high-octane"
foods.

A hummingbird would not live through the night if his heart, breathing and
body temperature did not slow down.
Oxygen is taken into the body through the lungs. It then passes into the
blood cells. In the cells it mixes with the food to make energy.

In birds there are air sacs next to the lungs. They never run out of breath.

The heart is the key for pumping their blood. A bird's heart beats much
faster than other animals. A bird's temperature is higher than mans'.

BATS:

A long time ago people thought bats were mice. People thought bats were birds.
Bats are mammals. Their bodies have fur. Bats are born alive. Bats do not come from eggs. They drink milk from their mother's breasts.
Bats live all over the earth. Most live in Africa.

Flight
Bats love to fly. Most bats fly at night. Bats are the only mammals that can fly.
A bat's body is made for flying. The neck is short. The chest is big. The stomach is small.
The bat's wings push the bat through the air.
A bat's wing has long bones. The long bones are covered with skin. The skin is very thin. Light can shine through skin.
The sides of the bat's body, legs and tail are covered with skin. The skin is special. It is thin and flat. The thin, flat skin helps bats fly.
A bat has thumbs. The thumbs do not have skin. A bat's thumbs help it to climb trees. A bat wing is like an airplane wing.
Some bats use their tails to catch insects.
Bats fly with a rowing motion.
Bats have large muscles in their backs and chests. These large muscles help bats move their wings.
Bats can move their wings one at time. Moving one wing helps bats stop.
Bats are true fliers. They use energy to flap their wings. Bats can glide through the air.