1. Bird Anatomy Notes

2. Anatomy 1.) Bones -Hollow but very strong
-Honeycombs inside bone for support
-Large eye sockets reduce skull weight
-Wing bones lighter, leg bones heavier
-All vertebrae but neck are fused together
2.) Muscles
-Large and relatively heavy
-Pectoral muscles=25% of total body weight

3. Anatomy 3.) Feathers -Four kinds, need to know 2 of them
a.) Contour feather (flight feather)
- Stiff central shaft
- Many side branches called barbs
- Barbs have interlocking barbules
b.) Downy feather – clustered at base of contour
-Short shafts with long fluffy barbs
-Insulate bird  trap air close to body
Preening = zipping up barbs that separated

4. Anatomy 4.) Crop and Gizzard -Crop is a storage area at the end of the
esophagus  softens food
- Gizzard contains small stones (and muscular
walls)  breaks food into small pieces
which travel to the intestines, where
nutrients are absorbed

5. Anatomy 5.) Reproduction -Male and female sex organs incredibly small
until mating season (hormones kick in!!)
- Testes swell as much as 300x bigger
-Most males have no external reproductive
structures = no penis
-Mating = touching male & female cloaca
(male stands on her back) *Some do while flying!
-Shelled egg, more yolk!
-Lots of parental care BOTH before & after
hatching

6. Anatomy 6.) Respiration -Continuous
-Lungs have a series of air sacs that are
always filled with fresh air, even when the
bird is exhaling!
-Birds need huge amounts of O2:
-Extremely high metabolism
-Extremely active

7. Bird Ecology “Barometers of an ecosystem’s health” Canary in coal mine
Important Roles of birds:
Pollination
Seed Dispersal
Insect Control
Rodent Control
Scavengers
**Key members of food chains!

8. Important Bird Behaviors
Complex mating behaviors
Nest building
Singing
Dances
Caring for young
**All inborn behaviors = not learned!
Example: Eagle nest can be 3m x 7m and weigh over 1,000 lbs! They also mate for life and use the same nest for life!

9. Important Bird Behaviors
Migration
Travel great distances (feeding grounds to mating grounds)
How?
Use landmarks (rivers, mountains, coastlines)
Star position
Follow the flock
Earth’s magnetic field
Greatest migrator= Arctic Tern
Flies from Greenland to Antarctica and back
22,320 miles!!

10. Bird Watching Builds appreciation and empathy Beautiful colors & songs
Interesting behaviors
(feeding, mating…)
ALSO
Indicators or environment’s health
If see/hear less birds:
Habitat loss (more farm, less forest = Cowbird parasites!!)
Introduction of Exotics (Guam snakes)
Pollution
Population of humans
Overharvest/Overconsumption (pet trade of tropical birds & chicken farming)