Birds

1. Birds Chapter 4 – Birds and Mammals Lesson 1

2. Characteristics of Birds • A bird is an endothermic vertebrate that has feathers and a four0chambered heart. • A bird also lays eggs.

3. Adaptations for Flight • The bodies of most birds are adapted for flight. • Feathers are not all the same. • A contour feather is one of the large feathers that gives shape to a bird’s body. • The long contour feathers that extend beyond the body on the wings and tails are called flight feathers. • Birds also have short and fluffy feathers known as down feathers which are specialized to trap heat and keep the bird warm. They are soft and flexible.

4. Obtaining Oxygen • Air sacs and a four chambered heart help birds obtain oxygen and move it to their cells. • The advantage of a four chambered heart over a three chambered heart is the oxygen rich blood does not mix with the oxygen poor blood. Therefore, blood carried to the cells of the body has plenty of oxygen.

5. Obtaining Food • Birds must obtain a lot of food to provide the energy needed for flight. • To capture, grip, and handle food birds mainly use their bills. • Many birds have internal storage tanks, also known as the crop for storing their food inside their bodies after swallowing it. • The stomach has two parts to break it down. In the first part food is bathed in chemicals in order to break it down. Than the food moves to a thick-walled, muscular part of the stomach called the gizzard. The gizzard squeezes and grinds partially digested food.

6. Keeping Conditions Stable • Birds use their food for energy. • To maintain their body temperature, birds use their feathers as well as their energy from food.

7. Reproduction and Caring for Young • Like reptiles, birds have internal fertilization and lay eggs. • Bird eggs are similar to reptile eggs except that their shells are harder. • Bird eggs develop at a temperature close to the body temperature of the parent bird. • Chicks may take from 12-80 days to develop, depending on its species.

8. Birds in the Environment • Birds are adapted for living in diverse environments. You can see some of these adaptations in the shapes of their legs, claws, and bills. • Birds play an important role in the environment. Some are pollinators and they are chief predators of animal that may be pests.