1. BIRDS
Class Aves

2. Characteristics Integumentary Skeletal
Feathers, bipedal (two legs covered in scales), syrinx (song box)
Skeletal
Endoskeleton; hollow bones; most can fly, large muscles for flight

3. Characteristics Circulatory Reproductive
4 chambered heart, 2 separate loops, complete separation of oxygen rich and oxygen poor blood
Reproductive
Internal fertilization, oviparous, amniotic eggs with hard outer shells
Right atrium
Left atrium
Complete division
Heart
Domestic pigeon
Left ventricle
Right ventricle

4. Characteristics Nervous Respiratory
Brain, adapted to quickly interpret signals, keen sight, good hearing, poor smell and taste
Respiratory
Lungs & posterior air sacs for gas exchange, air flows in a single direction, helps maintain metabolic rate

5. Characteristics Digestive Excretory
Esophagus
Crop
Liver
First chamber of stomach
Gizzard
Small intestine
Cloaca
Pancreas
Air sac
Kidney
Heart
Lung
Brain
When a bird eats,
food moves down
the esophagus and
is stored in the crop.
As digestion continues,
the food moves through
the intestines.
Undigested food is
excreted through the
cloaca.
Large intestine
The muscular walls
of the gizzard squeeze
the contents, while small stones grind the food.
Moistened food passes to the stomach, a two-part chamber. The first chamber secretes acid and enzymes. The partially digested food moves to the second chamber, the gizzard.
Digestive
Beaks that are adapted to type of food they eat, no teeth, crop, stomach, and gizzard
Excretory
Uric acid deposited in cloaca where water is absorbed

6. Characteristics
Body Temperature
Endothermic
Habitat
Land, migrate

7. Evolution
Evolved from extinct reptiles

8. Groups of Birds Pelican & Relatives Birds of Prey Parrots
Cavity-nesting birds
Perching birds
6. Herons & Relatives
7. Ostriches & Relatives