Transcript Unit 1 Notes

Elective Ornithology
Spring
Semester
What is Ornithology?
• Ornithology is the
study of birds.
Class Aves
• The taxonomic group
to which birds belong.
Characteristics of Birds
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Bipedal – walk on two legs
Vertebrates – have a backbone
Feathers – a unique body covering
Bill – varies in structure and function, but
always toothless and covered in a hard
sheath
Avian Body is Structured for Flight
• Hollow bones, fused together for strength
• Furcula (wishbone) that helps spring the
wings back out
• Wings are specialized for flight and
nothing else
Feet of tree dwelling (aboreal)
species
• When they bend to
squat, tendons lock
the toes around a
branch
Order Passeriformes
• Songbirds
• Most advanced with this “foot” locking
• Lock stable enough to perch and roost
Halux
• Most birds have a
large, opposable toe
known as a halux
Body Temperature
• Birds maintain a high
internal temperature,
40-44 degrees C
(104-111degrees F)
Respiratory and Circulatory
Systems
• Large heart
• Efficient flow through
the lungs
Reproduction
• Make large, elaborate
external eggs
• Most species mate for
life (monogamous)
• A few are
promiscuous
Intelligent!
• Large brains (6-11)
times larger than likesized reptiles
• Good learning ability
Voice
• Birds have the most
advanced sound
producing abilities of
all vertebrates
Navigation
• Birds use patterns of
earth’s magnetism,
celestial clues, and
polarized light (in
theory) to navigate
Sight
• Birds have good color
vision
• Birds can see into the
near ultraviolet range
of the spectrum
Hearing
• Better abilities than
humans
• They can hear
sounds of lower
frequency than
humans are able to
hear
Birds
Form and Function
Biodiversity
• Estimated 300 billion
birds of roughly
10,000 species
currently living on
earth
Evolutionary View
• Oldest bird-like fossil is Archaeopteryx
lithographica
• 155 million years old
• Had feathers, could possibly “fly”
• Said to have evolved to from dinosaurs to
what we know today
Archaeopteryx lithographica
Diversity of Size
• Size can vary greatly
• Smallest is 2 g
(hummingbird)
• Largest is 100,000 g
(240 lbs) (ostrich)
Different Ecologies and Behaviors
• Bill shape and function is a good example
• Diets vary; leaves, buds, fruits, nectar,
invertebrates, vertebrates and carrion
Wing Shapes Vary
• Vary according to the
bird’s lifestyle
• Long and narrow are
good for soaring
(northern harrier)
• Short and rounded
are good for agile
flight in thick
vegetation
Foot Anatomy
• Shows the diversity of
lifestyles birds utilize
Bird Names and Classification
Names and Classification
• Class Aves currently
has about 10,000
species
• All have a two part
scientific name
• Ex: Bald Eagle:
Haliaetus
leucocephalus
(means sea eagle
with a white head)
Orders
• Currently birds are grouped into 29
different orders
• Anseriformes – Ducks, geese, swans
• Ciconiiformes – Storks, herons, cranes
• Falconiformes – Raptors
• Piciformes – Woodpeckers
• Passeriformes - Songbirds
Biogeography
• The study of the geographical distribution
of life on earth
• Birds are found practically everywhere on
earth
• Avifaunas – regional assemblages of bird
species
Thomas Huxley
• An evolutionist that
said birds are merely
“glorified dinosaurs”
• He gave many
reasons for this
statement
Huxley’s Evidence
• Both birds and reptiles have:
1. A single ball and socket joint between the
skull and first vertebrae
2. Only one middle ear bone, the stapes
3. Scales on bird feet are similar to scales
on a reptile
4. Both lay amniote eggs
Archaeopteryx – The Flight Debate
• Could Archaeopteryx
fly? Scientists argue
about this.
The “No Flight” Argument
• Some scientists argue that because
Archaeopteryx lacks the supracoracoideus
muscle that lifts the wing after a flight
stroke, it could not fly.
The “Pro-Flight” Argument
• Had a large furcula
• Had feathers that resemble flying birds
and not flightless birds
Evolution of Feathers
• On hypothesis is that
they first evolved for
temperature
regulation.
• Another is that they
first evolved for flight
Process of Feather Evolution
Evolution of Avian Flight
How did wings evolve?
• It is thought that
wings evolved to help
in leaping and
balance in jumping to
catch prey.
After Archaeopteryx
• Next Sinornis
santensis was found
• Lived 140 mill years
ago
• Was saw toothed and
sparrow sized
Modern Birds
• First modern birds
were flightless
• A good example is the
2m tall diatrymas
• Had clawed toes, a
horse-sized skull and
eagle-like beak