1. Chapter 15.1b
Birds

2. Wings
Not all bird fly, but most wings are used for flight. Wing are attached to powerful chest muscles. Birds will flap their wings to gain thrust and go forward, lift, and stay in the air. Wings will move up and down, and back and forth.
The shape of the birds wings will help it fly. Wings are curved on top and flat or slightly curved on the bottom.
When a bird flies the air below the wing moves slower than air on top of the wing. This creates greater pressure on the bottom of the wing pushing the wing up.
Larger wings allow birds to be able to soar and glide without beating their wings.
Birds that don’t fly use their wings to swim or in courtship, or to maintain balance.

3. Digestive System
Birds need a lot of high energy food, like nuts, seeds, nectar, insects, and meat, so they can fly.
Food is broken down quickly in the digestive system to get energy.
From a bird’s mouth the unchewed food moves to the crop. This is an area that will store food until it absorbs enough moisture to move on. The food then enters the stomach where it is partially digested. It then moves into a gizzard. The gizzard grinds and crushes, with small stones, the food. Digestion finishes in the intestine and then the nutrients move to the blood stream.

4. Respiratory system
Body heat is made when food is combined with oxygen. A bird needs a good respiratory system to get energy.
Birds have 2 lungs. Each lung has balloonlike air sacs. Air flows one direction in the bird’s lungs. The receive air with oxygen when they inhale and when they exhale. This gives a constant supply of oxygen.

5. Circulatory System
A bird has a heart, arteries, capillaries, and veins.
They have a large 4 chambered heart.
A bird has a very fast heartbeat.

6. The Importance Of Birds
Birds can be a source of food and raw materials. Many birds are kept as pets.
Owls help controls pest by eating rodents.
Many birds eat insects and help keep insect populations in check.
Other birds are pollinators. They also help disperse seeds for plants.
Birds can be pests when they have a large population and their droppings causes a lot of damage.

7. Uses of Birds Humans hunt birds for food or fancy feathers.
Many birds have been domesticated to be used for meat and eggs (turkeys and chickens).
Feathers are used in mattresses and pillows. Down feathers are good insulators.
Bird droppings can be used as fertilizer.

8. Visualizing Birds Birds look very different based on what they eat.
Birds of prey have large claws and sharp beaks because they eat meat.
Seed eaters have a strong beak to crack seeds.
Insect eaters have a point beak that can pry bark or bore wood to find insects.
Waterbirds have webbed feet that help them move through water.
Flighless birds can be fast runners.
Wading birds usually have long legs so they can walk in shallow water.