1. Chapter 21-Birds

2. Class Aves- Birds ~8,700 species Forelimbs modified into wings
Amniotic eggs (hard-shelled)
Scaled feet and legs
Strong, light-weight skeleton
Endothermic metabolism (104° F to 108° F)
Completely divided ventricle
Oxygenated and deoxygenated blood completely separate
Highly efficient lungs
Syrinx- Bird’s song box

3. Bird Heart

4. Highly Efficient Lungs
One-way air flow
Air sacs store gas (more efficient)
Lungs exposed to only oxygenated air
Blood travels in opposite direction
Endothermic metabolism, completely divided ventricle, and efficient lungs account for energy needed for flight

5. Highly Efficient Lungs

6. Bird Skeleton Thin Hollow
Many bones fused for sturdy muscle attachment
Keel- Enlarged breastbone and fused collar bone
Breast muscles attachment (30% of weight)

7. Class Aves- Birds Brain to body size ratio second only to mammals
Digestion:
Beak lacks teeth
Crop- Expanded portion of esophagus stores food
2-chamber stomach:
Proventriculus - 1st – Digestive acids partially break down food
Gizzard- 2nd – Muscular; grinds and crushes
Waste exits cloaca
Covert nitrogenous wastes to uric acid in a harmless white paste form

8. Feathers Camouflage Covered in feathers (modified reptilian scales)
Develop from follicles (tiny pits in skin)
Molt feathers individually
Also function as camouflage or attracting mates
Sexual dimorphism- Males and females have different appearances
Males more brightly colored to attract females

9. Feathers Attract Mates
Male and female cardinals

10. Feathers Preening- Pulling feathers to relink connections
Follicles- Small sacs in skin where feathers develop
Two types:
Contour feathers- Cover body and give shape
Flight feathers- wings and tail
Protect and streamline
Rachis- Broad, flat part of feather
Vane- central shaft of feather
Branches (barbs) w/barbules (projections with hooks) interlock
Quill- bottom section of rachis (calamus)
Preening- Pulling feathers to relink connections
Preen gland- Secretes oil to clean and waterproof feathers
At base of tail
Down feathers- Insulate under contour feathers

11. Bird Feathers

12. Amazing Bird Flights
Hummingbird
Hummingbirds flap their wings rapidly (20-80 beats per second)
Smallest birds
Migrating birds can travel up to 2,000 miles in 6 days
Gulls and vultures use upward air movement to use little energy
Turkey Vulture

13. Bird Reproduction and Offspring
Monogamous- many bird species have mating pairs and mate for life
Clutch- a group of eggs in a nest
Incubate- Male or female parents keep eggs warm
Albumin- Egg white (protein)
Altricial- birds helpless at birth
Few eggs at a time
Stay in nest a long time
Ex: songbirds (i.e. American Robin)
Precocial- birds well developed at birth
Large numbers of eggs
Feed themselves
Ex: Ducks and chickens

14. Bird Diversity 28 orders (see page 329)
60% order Passiformes (song birds)
5,300 species; largest group of terrestrial vertebrates
Robin
Mocking bird

15. Bird Adaptations Adaptations based on habits and diet Sea gull
Beak (bill)
Legs
Feet
Some adaptations include
Stream-lined bodies for flying over water
Low-light vision for feeding at night (nocturnal)
Wings adapted for swimming
Sea gull
Barn owl

16. Flightless Birds Ostriches (Africa) & Emus (Domesticated)
Largest birds
Body to heavy for flight
Penguins (Antarctica)
Adapted wings for swimming
Emperor penguin family

17. Avian Adaptations

18. Avian Adaptations

20. North American Flyways

21. Long Migration Flight

22. http://player. discoveryeducation. com/index. cfm