1. Birds – Class Aves

2. Evolution and Classification
Birds are Vertebrates of the Class Aves
Warm blooded
The study of birds is called Ornithology

3. Origin and Early Evolution
Evidence from fossils and from studies of comparative anatomy indicates that birds evolved from reptiles
Their features and their fragile hollow bones do not preserve well.

5. Archaeopteryx
The fossil genus Archaeopteryx link between reptiles and birds, these mammals possessed characters of both reptiles and birds.
Like reptiles it had a large skull with teeth, bones that weren’t hollow, claws on its forelimbs, and a long tail.
Its strong legs and rounded wings indicated that it glided rather than flew

7. Characteristics of Birds
Body covered with feathers
Bones are thin and hollow
A toothless, horny beak in present
Endothermic
The 4-chambered heart
Amniote eggs are encased in hard, calcium-containing shells.

8. Endothermy Generate and regulate body heat internally
Enables birds to inhabit both cold and hot climate
Body temperature ranges from degrees Celsius.(104 – 113 degrees F)
To help conserve body heat, birds fluff out there feathers to insulation.
Birds have a 4-chambered heart that allows oxygen to be distributed with maximum efficiency. The heart will beat up to 150 to 1000X/minute.

9. Respiration To maintain body temperature bird’s breathe rapidly
Air sacs in lungs bring in more oxygen
One-way flow of air from air sacs to lungs.

10. Digestive and Excretory system
Food passes from the mouth cavity straight to the esophagus.
Enlargement of the esophagus called the crop stores and moistens food.
In the first chamber, The proventriculus, gastric fluids begin breaking down the food.
Then passes through the gizzard, a muscular organ that kneads and crushes the food

11. Excretory System
The avion excretory system is also efficient and light weight
The two kidneys filter a nitrogenous waste called uric acid from the blood
 highly concentrated uric acid travels by ducts called ureters to the cloaca, where along with undigested matter from the intestines, it is excreted in a semisolid, usually white mass

14. Beaks and feet
Hawks and eagles have powerful beak and clawed talons that help them capture and then rip their prey.
Swifts have a tiny beaks that opens wide like a catcher’s mitt to share insects in midair.
The feet of flightless birds, on the other hand are modified for walking and running

15. Skeletons and Muscles Combine lightness and strength
Bones are thin and hollow
Furculum (wishbone) fused collarbone that stabilizes bird in flight.
Fused bones form a sturdy frame that anchors the powerful breast muscles during flight and supports the muscles when a bird is walking or at rest.

16. Skeleton The keeled sternum supports the large breast muscles
The humerus, ulna, and radius, along with the pectoral girdle and the sternum, support the wing.
Flight muscles (pectorals) are attached to wing & keeled sternum
Muscles make up 50% of the birds body weight.

17. Classification
Most taxonomist classify the nearly 9,000 species of Class Aves into 27 orders
To classify birds into orders and families taxonomists most often use morphological evidence from beaks, feet, plumage, bone structure, and musculature.

18. Feathers Modified scales Function: lift for flight
help conserve body heat
Feathers are the single most important characteristic that separates birds from living reptiles and all other living animals. Made from proteins in pits in the bird’s skin.

19. Parts of a feather Follicles, shaft, two vanes, barbules.
Barbules – have microscopic hooks that hold barbules together
Birds preen their feathers to clean them & coat them with oil.
Preen glands are oil glands located at the base of the tail.

20. Types of feathers Down feathers Soft and fluffy Cover body of babies
Provide undercoat insulating adult birds

21. Countour Feathers: Flight Feathers Give streamline shape to body
Provide coloration to adult birds
Give additional insulation to body
Flight Feathers
Specialized contour feathers
Found on wings & tail

22. Molting Birds shed or molt feathers periodically
Usually in late summer between breeding & migration.
Flight feathers are replaced
Some birds molt before courtship

23. Order - Passeriformes Includes half of all bird species.
“perching” birds
Large rear toe to provide better grip on branches.
Food: nectar, seeds, fruit & insects
Examples: robins, blue jays, wrens, cardinals

24. Order - Apodiformes Small, fast flying birds. Tiny feet
Long, slender beak
Eat insects (sometimes in flight) or lap nectar from flowers.
Examples – hummingbirds and swifts

26. Order - Columbioformes
Plump-breasted
Small head
Short neck, legs, beak
Slender bill
Feed on fruit and grain
Examples – pigeons and doves

29. State Bird of Alabama
Yellowhammer
Northern Flicker