Ch' 44 Birds

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Ch. 44 - Birds

• Class ? Aves
• No other vertebrate is as well adapted to life on
  land, air, water.
• The study of birds ? Ornithology
• Archaeopteryx was the 1st reptile-like bird
  fossil known.

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Characteristics of Birds

• 1. Feathers
• 2. Endothermic warm-blooded
• 3. 4-chambered heart
• 4. All lay eggs
• 5. Most without teeth (beaks)
• 6. Hollow bones (most)
• 7. Forelimbs modified into wings
• 8. Hind limbs for walking, swimming, or perching

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• These are modified scales in a bird.
• Feathers
• The 2 main types of feathers are contour down
  feathers.
• Parts of a Feather Quill? Shaft? Vane (made up
  of barbs) ? Barbules with hooks
• Draw a feather

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• Each barb on the vane is attached to the next
  barb by the barbules hooks.
• A bird uses a preening technique to repair any
  split vanes by rehooking the barbules with its
  beak.
• The down feathers are the fluffy short feathers
  close to a birds skin.

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• Most water fowl use their tail gland to spread
  oil on their feathers to keep them water proof.
• Whats the term for birds replacing their
  feathers?
• A grown feather is a dead structure that
  eventually breaks off through shedding.

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2 Types of Molts

• 1. Serial molt feathers are lost in series
  flight is still possible.
• 2. Eclipse molt contour feathers are all lost a
  once the bird cant fly. Examples???
• Birds usually molt during late summer after
  nesting season before migration.

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Skeleton

• Hollow bones that have struts.
• Long neck with a atlas and axis vertebrae that
  rotate the birds head.
• Sternum or breastbone that is fused to the
  clavicle.

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Metabolism

• All birds undergo endothermy, which is the
  maintanance of a constant body temperature.
• Birds need a high metabolism in order to sustain
  flight.
• A birds body temperature is between 104 107 F.
• This is one of many reasons why human cant fly

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Digestive System

• Enters an elastic esophagus ? crop ? stomach (
  proventriculus gizzard) ? intestine ? cloaca
• Most birds swallow gravel for their gizzard to
  grind food.
• Birds of prey form pellets of indigestible
  materials that are regergetated as owl pellets.

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Respiratory System

• 2 cycle system
• Mouth ? trachea ? syrinx ? brochii (2) ? lungs ?
  posterior air sac 1st cycle is complete
• 2nd cycle back to the lungs ? anterior air sac ?
  back out through the mouth (exhale)
• This allows the bird to have air in its body at
  all times.

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Circulatory System

• How many chambers?
• Draw the heart
• Heart Beats
• Turkey ? 93 beats/min
• Chicken ? 250 beats/min
• Black-capped chickadee ? 1,000 beats/min

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Nervous System

• Birds have large brains for their size
• 3 main parts
• 1. Cerebellum balance movt
• 2. Cerebum controls all intelligence
• 3. Optic lobes for vision
• Rods ? for dim vision
• Cones ? for color vision

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Reproductive System

• The male bird produces sperm in the 2 testes,
  which travels through the vas deferens to be
  released.
• The female bird usually have 1 ovary on the left
  side, which releases an egg into the oviduct
  where it is fertilized.

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• The eggs are then incubated with a featherless
  patch of skin on their abdomen called a brood
  patch.
• Can you name some different types of nests?
• Some birds lay their eggs in others nest.
• Cuckoo, starling, cowbird

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Hatchlings (2 types)

• 1. Precocial
• Birds born with down feathers
• Ex. Ducks, quail, geese (water birds)
• 2. Altricial
• Birds born naked helpless
• Demand a lot of food
• Ex. Most birds
• Which one of these is incubated longer?

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Migration

• Greatest adventure risk for a bird.
• Do all birds migrate?
• Many birds migrate back to the same spot each
  year.
• Several male bird species undergo courtships to
  display their colors and dominance. This is
  called a lek. Examples?

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Ratites ? Flightless Birds

• 1. Ostrich
• Africa, 2 toes, very fast (35 mph)
• 2. Rhea
• S. America, 3 toes, smaller than the ostrich
• 3. Emu
• Australia

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• 4. Cassowary
• Australia, very tem0permental bird
• Known to attack humans with long dagger-like
  claws
• 5. Kiwi
• New Zealand, smallest ratite
• Lays a 5 in. egg that is about 1/3 its body
  weight.

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• Penguins are also flightless, but they had flying
  ancestors that lost the use of their wings
  flight was no longer useful to their mode of
  life.
• Binocular vision
• Overlapping vision
• Owls have the best binocular vision (flat face)
• Sparrows have very little eyes near their sides
• Woodcocks have little if any.

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