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