Transcript Ch. 34 - Birds

Ch. 42 - 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.
• Video
Characteristics of Birds
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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
• Video
• 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
• Video
• 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 bird’s skin.
• Most water fowl use their
tail gland to spread oil on
their feathers to keep
them water proof.
• What’s the term for birds
replacing their feathers?
• A grown feather is a dead
structure that eventually
breaks off through
shedding.
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 can’t fly.
Examples???
• Birds usually molt during late
summer after nesting season
before migration.
• Video
Skeleton
• Hollow bones that have
struts.
• Long neck with a atlas
and axis vertebrae that
rotate the bird’s head.
• Sternum or breastbone
that is fused to the
clavicle.
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 bird’s body temperature is
between 104 –107 F.
• This is one of many reasons
why human can’t fly
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.
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.
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
• Video
Nervous System
• Birds have large brains for
their size
• 3 main parts
• 1. Cerebellum – balance &
mov’t
• 2. Cerebum – controls all
intelligence
• 3. Optic lobes – for vision
– Rods  for dim vision
– Cones  for color vision
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.
• 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
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?
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?
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
• 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.
• Video
• 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