Post on 13-Jan-2016
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
• 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 like-sized 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