CLASS AVES

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CLASS AVES BIRDS
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• External structures
• A. Plumage- feathers
• 1. Function-
• a. for flight (lift steering)
• b. Maintain body temp.
• 2. Structure-
• a. Contour feathers- cover body,
  wings, and tail- used for flight.

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b. Down feathers- under contour-
used for insulation. c. Filoplume
feathers- under contour used as sensory
structures.
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3. Maintenance- a. Preening- use oil from
preen gland at base of tail to
waterproof feathers. Also
reattaches feathers to keep in good
flying condition
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b. Anting - rub ants on feathers. Formic
acid secreted by ants kills
feather mites. c. Molting - several
times throughout life. Contour
feathers shed a few at a time so
that they are still able to fly.
Passive anting- birds lays flat, ants crawl over
body.
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• Beaks and feet adapted for habitat feeding
  habits

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C. Wings- 1. Wings used for flight
2. Tails used for steering, balance, braking.
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• Bones
• A. Lightweight yet strong
• B. Porous w/internal struts for support
• C. Fewer skull bones
• D. No teeth- lightweight bill instead
• E. Sternum- large breastbone with keel
• for attachment of large flight muscles

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III. Muscles A. Must contract quickly
fatigue slowly. B. Have many mitochondria
to produce lots of ATP/energy for
flight. C. Some have special tendons that
lock ankle joints in place so they can
sleep without falling out of trees.
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• Circulation-
• A. 4 chambered heart
• B. Heart beats fast- distributes nutrients
• oxygen fast for production of energy

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• Respiration
• A. breathe in through nares(nostrils)
• B. pathway of air
• nostrils trachea - larynx(voice box)
  -
• lungs - air sacs
• C. air sacs store extra oxygen for production
• of energy.
• D. air sacs are always full
• of oxygen

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• Temperature Regulation-
• A. Endothermic- warm-blooded
• B. Enables them to live on every continent
• C. Adaptations to control temp.
• 1. Fluff feathers when cold.
• 2. Tuck beaks into feathers- reduces heat
• lost from respiratory tract
• 3. Shiver
• 4. Pant

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• Nervous/Sensory
• A. Forebrain- includes region called corpus
  striatum that functions in visual learning,
  feeding, courtship and nesting instinct.
• B. Vision is the dominant sense
• C. Nictitating membrane
• D. Olfaction- not very strong except in
• scavenging birds
• E. Hearing is well developed

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• Excretion
• A. Excrete uric acid
• B. Cloaca reabsorbs water before wastes
  pass out. Results in chalky white residue
• C. Salt glands- marine birds have these
  to excrete excess salt from bodies.

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• Digestion/Nutrition-
• A. Beaks and tongues are adapted for different
  food sources
• B. Path of food
• 1. Mouth
• 2. Esophagus
• 3. crop (storage)
• 4. proventriculus (secretes
• gastric juice to begin digestion)
• 5. ventriculus (gizzard for grinding)
• 6. intestines (absorb nutrients)
• 7. cloaca (where wastes eliminated)

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C. Ravenous appetites a. Need to maintain
energy for flight b. Helps maintain body
temperature D. Digest food quickly- so are not
weighed down
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X. Reproduction development A. Oviparous B.
Fertilization occurs by close cloacal
contact during brief mating sessions. C. No
external genitalia to transport sperm to
egg. D. Amniotic egg- eggshells are fragile
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• E. Males bright colors to attract females.
• F. Females dull color to blend in with nest.
• G. 90 of all birds are monogomous- stay with
  same mate throughout season. (some for life-
  ducks)
• H. Usually one parent stays with eggs while
  other searches for food.

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I. Some are polygamous- males mate with more
than one female. (Chickens)

• J. Nest is made by female after mate found
• K. of eggs vary. Usually turn eggs to prevent
  membranes from sticking causing deformed embryo.
• L. Eggs incubate 10-80 days.

Bluebird eggs
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• Chick breaks air sac at blunt end of egg with
• egg tooth at tip of beak.

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N. Hatchlings can be 1. Altricial- naked when
they hatch and entirely dependent on
parents. Ex bluebird robin
Usually tree dwelling birds.
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• 2. Precocial- some down feathers when they
  hatch and can walk, run, swim and feed themselves
• O. Only 50 of eggs laid will yield birds that
  leave nest. Strongest, most vociferous will get
  food survive.
• P. Migration- in response to temp, instinct,
  seasonal changes.

Usually ground dwelling birds.
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• Which characteristic do reptiles and birds share?
• a. Amniotic eggs b. Feathers c. Jacobsons
  organ
• A hatchling that can walk, feed, etc by itself
  (like a duck) is a/an __________ hatchling.
• a. Altricial b. precocial
• Birds are the only animals on earth that have
• a. Amniotic eggs b. Feathers c. Dry scaly
  skin
• Birds belong to class
• a. Raptor b. Reptilia c. Aves
• The feather that is used for insulation is
• a. Contour b. Down c. filoplume

Daily Quiz 1