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: A single ball and socket joint between the skull and first vertebrae Only one middle ear bone, the stapes Scales on bird feet are similar to scales on a reptile 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