Birds meet their needs on Land, in Water, and in the Air

• BIRD SPECIES LIVE IN MOST ENVIRONMENTS

• BIRDS CAN MAINTAIN BODY TEMPERATURE

• MOST BIRDS CAN FLY• BIRDS LAY EGGS WITH HARD SHELLS• MOST BIRDS TAKE CARE OF THEIR

OFFSPRING

Birds live in most Environments• Penguins in Antarctica, parrots in the

tropics. Pelicans scoop food from water, cardinals crack open seeds. Over 10,000 species of vertebrae animals called birds.

• Many birds travel long distances during their lives. Some migrate with changing seasons, while others travel great distances looking for food.

• Birds have the following characteristics:

– 1: have feathers and a beak

– 2: have 4 limbs (Pair of wings and pair of scaly legs)

– 3: their eggs have hard shells

Birds maintain body temperature• Birds are Endotherms (keep a constant body temp.

regardless of environment). Stay active in colder climates by generating body heat & keeping it near bodies.

• Endotherms eat lots of food to generate heat (not like ectotherms); so birds in cooler climates must eat more.

• Soft feathers (down) keeps warm air close to bird’s bodies. Contour feathers cover the down & usually are water resistant.

• Birds shiver when cold, causing muscles to generate heat. They also cool down by fluffing feathers, releasing heat (instead of sweating).

Most Birds can Fly• Only 3 animals adapted flight: birds, bats,

& insects.

Most Birds Can Fly• Birds must be strong & light :

– Endoskeleton: some bones fused without joints so lighter & stronger but not flexible

– Wings & Feathers: contour flight feathers designed for lifting & gliding, to push against air.

– Special Respiratory System: air sacs & lungs let lots of oxygen move through birds body to release energy

– Hollow Bones: Many bones are hollow, with crisscrossing structures inside giving much strength without too much weight.

Birds also have internal gizzards to grind food so don’t need heavy jaws & teeth. Have keen sense of sight & hearing, important for flight.

Flight lets birds search for food in & migrate to different environments & escape danger

Birds lay Eggs with Hard Shells• Birds reproduce sexually. Many ways

to attract mates (sing, colorful feathers, fight, build neat nests, show off flight skills, etc.)

• After internal fertilization, (hard)shell forms around fertilized egg while inside female

• Female usually chooses where to lay eggs (often in nest). Bird eggs needed constant warm temp. to develop properly, so birds usually sit on nest to incubate them.

• Baby birds must be cared for (usually both parents provide food, protection & warmth).

• Some birds (ducks) hatch already seeing & walking so 1 parent needed.