1. Chapter 4
Section 1 - Birds

2. Characteristics of Birds
A bird is an endothermic vertebrate that has feathers and a four-chambered heart. Also lays eggs.

3. Adaptations For Flight
Birds bones are nearly hollow
Flying birds have large chest muscles that move the wings
Feathers help them fly
Birds are the only animals with feathers

4. Types Of Feathers
1. Contour Feathers – Largest type of feather, it gives shape to it’s body (balance and steer)
2. Down Feathers – Trap heat and keep the bird warm. Found next to the skin. Soft and flexible

5. Obtaining Oxygen
Birds have a system of air sacs that connect to their lungs.
These sacs enable the birds to obtain more oxygen from each breath of air than any other animal
Heart is 4 chambers, 2 atria, 2 ventricles

6. Obtaining Food Use bills to capture, grip, and handle food
Bills are shaped to help birds feed quickly and efficiently
Examples: 1.pointy, curved bill – meat hook 2. duck’s bill – kitchen strainer

7. Obtaining Food Cont. After a bird eats its food, digestion begins
Many birds have an internal storage tank, or crop, for storing food inside the body after swallowing it
Then moves to the stomach where chemicals break down the food.

8. Obtaining Food Cont. The food then moves to the gizzard.
The gizzard squeezes and grinds the partially digested food. (the gizzard acts as teeth)

9. Keeping Conditions Stable
Birds actually eat a quarter of its body weight
Have two types of feathers to keep their bodies warm

10. Reproduction and Caring for Young
Birds have internal fertilization and lay eggs.
Eggs only develop at a temp. close to the body temp. of the parent bird so this is why the parent bird sits on the eggs.
Parent birds protect their young until they are able to fly.

11. The Physics of Bird Flight
Section 2
The Physics of Bird Flight

12. Movement and Air Pressure
Moving air exerts pressure
The reason why the paper blew up is because the air blowing across the top of the paper was in motion. This moving air exerted less pressure on the paper than the air beneath it, so the paper rose.

13. Air Movement Around A Wing
The difference in pressure above and below the wings as a bird moves through the air produces an upward force that causes the bird to rise.
This upward force is called lift

14. Birds In Flight
To get into the air, a bird pushes off with its legs and moves forward at the same time.
Three types of bird flight are: flapping, soaring and gliding, and diving.

15. Flapping
To flap, a bird must sharply pull down its wings as it did when it pushed off the ground
Flapping requires a lot of energy

16. Soaring and Gliding Involves little wing movement
Soar and glide with their wings extended
When soaring, birds use rising currents of warm air to move upward.
When gliding, birds use falling currents of cool air to move downward

17. Diving
This type of flight does not use lift
Birds that hunt their prey from the sky may use diving flight
Pulling in the wings changes the birds’ body shape