Ornithology

Afrotropical

1550 species

Antarctic

35 species

Seabirds

Australasian

900 species

Emus, bowerbirds, birds of paradise

Indomalayan

2400 species

Nearctic

750 species (migratory)

Relatively low diversity

Neotropical

3700 species

"Bird continent"

Oceanian

Low diversity

Unique species by island

Palearctic

1025 species (migratory)

Largest realm

Likely origin of birds

• Fusion/reduction of bones
• Pneumatic bones
• Small size
• Forelimbs specialized for flight
• Centralized body mass
• High metabolism
• Developed nervous system
• Good vision

• Feathers as modified scales
• Scales on legs
• Single occipital condyle
• One middle-ear bone
• Lower jaw
• Nuclei in red blood cells
• Ankle structure
• Lay eggs
• Urogenital system

Theropod Dinosaur: transitional species, uncinate processes, incubation of eggs & nests, 3 digit foot, protein similarities, tail reduction. Against: dinosaurs had feathers but did not fly 

Thecodont: some tree dwellers, laterally compressed. Against: no fossil evidence of feathered thecodont

The arboreal hypothesis proposes that evolution of flight began in trees where a bird would use feathered limbs to glide or parachute downward. Evidence: dinosaur fossil with feathered hindlimbs

The cursorial hypothesis proposes that evolution of flight began on the ground when birds would use feathered limbs to provide balance and momentum while running. Evidence: WAIR

• History - continental drift, climate change, adaptive radiations, modern introductions
• Ecological tolerances - current climate, environmental conditions, habitat, interspecific interactions
• Dispersal barriers, vagility, physical barriers, interaction barriers, chance

• Vaned feathers: flight, contour
• Downy: down, semiplume
• Other: bristles, filoplumes

• Protection
• Prevent desiccation
• Temperature regulation
• Locomotion (flight, swimming, WAIR)
• Behavior (display, sound)
• Provisioning of young

• A Theropod
• 125 million years ago
• Not for flight
• Many other theropods

• Beta-Keratin
• Rigidity
• Hydrophobic

• Feather wear and tear
• Reproductive displays (breeding)
• Camouflage
• Parasites
• Birds molt from the inside feathers outward

• Lift vs. gravity
• Thrust vs. drag
• Alula reduces turbulence from the air moving over the wingcovert feathers and reduces turbulence

• Thermal or slope soaring (vultures)
• Dynamic soaring (albatross)
• Flapping (in formation - reduces energy costs)
• Hovering
• Intermittent flight (flap bounding and gliding)

• Pneumatic bones
• Feathers—dead
• Elimination of most skin glands
• Toothless bill (beta keratin)
• Loss and fusion of some bones
• Keeled sternum
• Sclerotic ring - rapidly focusing eye
• Air sacs
• Oviparous, gonad atrophy
• Rapid digestion
• Uric acid—no urine fluid or bladder

• Endothermic w/4 chambered heart (300 beats/minute)
• Energy rich diet—rapid metabolism (40-42 C)
• High glucose content in blood (twice humans)
• High pressure circulation
• Efficient respiratory system (coordination with wing beats)

• Area of the wing vs. weight of the bird
• Lower wing loads are not as fast, but are more maneuverable

• Wing length vs. chord length (width)
• High aspect are long narrow wings
• Low aspect are short wide wings

• Wishbone (furcula) = production of negative pressure
• Acts in concert with wing beats
• Leads to increased respiration rate
• In starlings, it acts as a spring bending laterally during the downstroke by the pectoralis and recoiling during the upstroke by the supracoracoideus

• Efficient and lightweight
• Digest a variety of foods
• Digest very quickly (inefficient)
• Food passes through their bodies in ~5-20% of the time it takes mammals and reptiles of similar size

• Proventriculus (glandular stomach)
• Ventriculus (gizzard)
• Practically no cecum, nutrient intake happens primarily in intestines
• Bile and pancreatic fluids pass with food

• Birds - uric acid, low solubility
• Mammals - urea dissolved in urine

• Coprodaeum - waste
• Urodaeum - ”urine” and sperm or eggs
• Proctodaeum - ejection

• Clean
• Heat
• Remove water
• Olfactory receptors

• Older than “birds”
• Usually nine, but ranges from 7-12
• No oxygen exchange
• “Bellows”
• Sound production

• Heat transfer
• Oxygen and Carbon Dioxide transfer from muscles
• Glucose
• Fatty acids
• Hormones

• 4 chambers
• Large
• High Pressure
• Lower heart rate

• Facultative hypothermia
• Many birds up to 6 C
• Humminbirds (8 - 20 C)
• Common poorwill (4.3 C)

• Small organs regulating hormones, growth, metabolism
• Endocrine because no ducts—directly into blood stream

Excretory and reproductive systems

• No penis
• No scrotum
• One ovary, a few exceptions

• Mammals excrete urea (toxic, dilution)
• Birds excrete urates (insoluble)
• Adaptation for water conservation
• Eggs

• Pigeons 725 different visual patterns
• Tool use
• Episodic memory in jays—recall of events
• taking place at a specific time or place
• Owls have sophisticated hearing—developed
• via learning
• Parrots—vocal learning
• Parrots communication
• Jays plan for future
• Spatial memory
• Count