BIRDS
class: Aves Chapter 42
Birds are the most
diverse &
widespread
terrestrial
vertebrates
What characteristic is unique to birds?
• Wings?
– Also found in bats (mammals), flying
arthropods
• Beaks?
– Also found in Turtles (reptiles), (squid)
cephalopods
• Bills?
– Also found in : platypuses (mammals)
Feathers are unique to birds
There are seven characteristics
all birds share:
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Feathers
Wings
Lightweight, rigid skeleton
Endothermic metabolism
Unique respiratory system
Beak
Oviparity
1. Feathers
*Unique to birds (NO OTHER ANIMALS HAVE THEM!)
*are modified scales that serve 2 functions:
-providing lift for flight
-conserving body heat.
*Feather Parts:
-shaft
-two vanes
-barbs
-barbules
How do birds stay warm in
the winter?
• Feathers!!!
– Down feathers
are very
insulating vs
cold.
• Down jacket anyone?
3 Types of Feathers:
• Down feathers - soft, fluffy feathers
that cover young birds and provide an
insulating undercoat in adults
• Contour feathers - smooth feathers
that give adult birds’ bodies a streamlined
shape and provide insulation
• Flight feathers - specialized contour
feathers located on the wings and tail that
are long and rigid
3 types feathers
Downy
Contour
Flight
http://www.kidwings.com/bodyparts/feathers/types/index.htm
Feather Care:
• Preening occurs when birds use their
beaks to rub their feathers with oil.
• Preen gland
– located at the base of the tail
– secretes oils that keep feathers healthy &
waterproof.
• Molting - Birds periodically shed and
regrow their feathers.
Birds who’s feathers get soaked
through with oil usually freeze to death
These guillemots are covered in oil. The feathers on their bellies should be pure white.
Dozens of oil victims are cared for every year in the bird sanctuary at Ecomare. They are
washed in a special bird washing machine. Afterwards, they need time to gain back their
strength and get their plumage back to its water-repellent state. Eventually, they are
returned to the open sea. Only 10% of the birds immersed in oil wash ashore alive. The
rest die at sea.
http://www.ecomare.nl/kijkje_ecomare/detail.asp?pageid=518&page=1
2+3. Wings & Light-weight Skeleton
• Skeleton is light and strong.
• Bones are thin and hollow.
• Many bones are fused
*more rigid than a
reptile or mammal‘s.
* Furcula- The fused
pair
of collar bones = “WISHBONE”
*A large keel-shaped sternum allows
attachment of large flight muscles.
Avian Skeleton
More Flying Adaptations
• Birds have large, powerful flight
muscles in the breast and wings.
• In some birds, flight muscles account
for up to 50% of the body weight.
• The Pygostyle, fused terminal
vertebrae, supports the tail feathers.
• Pectoral muscles form the bulk of the fleshy mass &
about 15 to 20 percent of the bird's total body weight.
• www.paulnoll.com
4. High Metabolism
• Endothermic.
• Very high metabolic rate.
– Rapid breathing
– Rapid digestion of lots of food
(A thrush can eat blackberries, digest them & excrete
seeds 45 mins later.)
• Maintains a body temperature of 104-106
degrees F.
The avian circulatory system is
similar to that of both crocodiles and
mammals.
• Birds have a four chambered heart.
• Deoxygenated blood is completely
separated from oxygenated blood in the
heart.
• Birds have a relatively rapid heartbeat.
• Unlike mammals, avian red blood cells
have nuclei.
5. Unique Respiratory System
• Most efficient respiratory system of any
terrestrial vertebrate.
6. Beak
• Jaws covered by tough
horny sheath
• No modern birds have
teeth.
– (Achaeopteryx (bird
ancestor) had teeth)
• Birds must swallow
gravel
or small rocks to help
grind food in the
gizzard.
www.mun.ca
The Avian Digestive System:
• Beak - breaks open or tears apart food
• Esophagus - passage from the mouth to
the crop
• Crop - stores and moistens food
• Stomach - consists of two parts
– proventriculus - digestive enzymes break
down food
– gizzard - kneads and crushes food aided by
stones which the bird swallows
• Small intestine - absorbs nutrients
• Large intestine - absorbs water
• Cloaca - eliminates wastes from the body
7. Oviparity
• Lay Amniotic eggs in a hard
calcium containing shell.
• Internal fertilization.
• Usually lay their eggs in a nest.
• One or both parents warm (incubate) the eggs
and guard the nest.
• Birds sit on their eggs and cover them with a
thickened featherless patch of skin called the
brood patch.
• Birds usually provide extensive parental care.
Birds have two general patterns
for rearing young.
• Precocial:
– Young incubate for long periods.
– Young can walk, swim, and feed as soon as
they hatch.
– This pattern is most often seen in groundnesting birds.
• Altricial:
– Eggs hatch quickly.
– Young hatch blind, featherless, and helpless
and require extensive parental care.
– This pattern is most often seen in birds that
nest above ground.
Parts of a Bird
www.geocities.com/easternbirds/Birds.html
Internal structures of a bird
Phylogenic diagram of relationships to birds
Similarities between birds &
some dinosaurs:
• Flexible S-shaped neck
• Unique ankle joint
• Hollow bones
Oldest known bird fossils: genus Archaeopteryx,
which date from the late Jurassic period, have
characteristics of both dinosaurs & birds.
Hypothesizes on Origin of Flight
• Ancestors of birds were tree dwellers
that developed the ability to glide
between trees.
• Ancestors of birds were grounddwelling & first used feathers to
stabilize them when they leapt after
prey.
How many different kinds of
birds can you name?
•Pennsylvania Game Commission photo
gallery:
•http://www.pgc.state.pa.us/pgc/cwp/vie
w.asp?a=458&q=162298
Good Field guide to birds
http://www.bdi.org
Birds are divided into 23 orders.
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Ten of the most familiar orders are listed:
Anseriformes (swans, geese, ducks)
Strigiformes (owls)
Apodiformes (hummingbirds & swifts)
Poittaciformes (parrots,parakeets, macaws,cockatoos)
Piciformes (woodpeckers, toucans)
Passeriformes (*the biggest group w/more than
half total # bird species) (Robins,warblers,bluejays,wrens)
• Columbiformes (pigeons & doves)
• Ciconiiformes (penguins, storks, herons, egrets,
raptors, vultures)
• Galliformes (Turkeys, pheasant, chickens, quail)
• Struthioniformes (**largest birds)
(ostriches, emus, cassowaries)
Pennsylvania Audubon Society
• http://pa.audubon.org/AboutUs_History.html
• Another good site:
• URL:
http://www.ohiovalleyoutdoors.com/id_on_th
e_wing.htm
Assignments:
1. Read page 850 in textbook
• Answer 3 questions page 850
2. Read section 42-3
• Answer questions 1-8
3. Write the name of each of the ten most common orders
listed in your book, then write down the type of birds in
the order & at least 3 adaptations for each group
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Anseriformes
Strigiformes
Apodiformes
Poittaciformes
Piciformes
Passeriformes
Columbiformes
Ciconiiformes
Galliformes
Struthioniformes
Avian Adaptations
Questions
1.
Which of the following characteristics of Archaeopteryx
is not shared by modern birds?
A. tail
B. teeth
C. furcula
D. feathers
2. Which of the following characteristics do birds share with
dinosaurs?
F. crop
G. lack of teeth
H. presence of feathers
J. structure of the ankle joint
3. What is the function of the preen gland?
A. to produce digestive enzymes
B. to control salt balance in the body
C. to release scents that help attract mates
D. to produce an oily substance used to condition
the feathers
4. Which bone supports the tail feathers?
F. ulna
G. furcula
H. pygostyle
J. pelvic girdle