Characteristics of Birds

Reference Chapters 1-2

ADVANCED LEC

02ORNITHOLOGYUniversity of Rio GrandeDonald P. Althoff, Ph.D.

Characteristics of Birds Result in…

• Efficient mode of _________________

• Further ______________ (i.e., higher levels of process some sensory input)

• Promote _____________

• Increased ______________ efficiency

• Improved senses of _______ and ________

Accomplished by being able to….

• __________

• __________

• ________________ under adverse conditions

Graham Owen Gallery

FLIGHT

Flight: KEY STRUCTURES

• ________• Feathers• Feathers• Feathers• Feathers ___________

• ….and some _____________

Perfection of ENDOTHERMY

• Allows activity under _______ environmental conditions

• Specialization of __________ anatomy (i.e., wings & feet have enabled efficient use of this bigger activity window)

Birds arose from _________ STOCK

Similarities to reptiles include….• ____ occipital condyle (mammals have 2)

• Lower mandible articulates with movable _________ bone (mammal’s lower mandible hinged directly to skull—at least for many species)

• Ears have _______ bone

Single “ear bone”(common to birds,

amphibians, reptiles, and

Key MORPHOLOGICAL trends towards…

• Overall, a ______ skeletal structure--transformed wrist and shoulder--”some” hollow bones (as noted)--evolution of the bastard wing—or ______, which prevent _________ at low speeds

• Muscular design that provided a __________ that could produce the main components of flight: _____________

Gill Fig. 5.5 (p121): The slot created by the extended alula keeps the airflow close to the wing during takeoff and landing.

A) Steep angle of attack w/o ALULA

B) Steep angle of attack with ALULA

alula

Key characteristics….that were improvements over reptilian stock…

• Feathers• Wings• Lightness• _____________________• _______________–must make “quick” adjustments in

focus because one is often moving faster• _______________• _______________• _________________________• _________________________

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Feathers

• _____________ air-resistance

• Control heat loss (hot conditions) /retention (cool conditions (i.e., ______________)

• ____________________

• Wings—conquer air space * read Gill p40: what is difference between _________ theory vs. _________ theory for development of forelimbs into wings?

Lightness

• Feathers: “the” __________ materials for their size and weight known ! ! !

• No _________ nor _____________

• No ________ (….forget about the egg tooth!)

• _______________________ bones

Lightness…con’t

• Radical _________ of intestines

• __________ of urinary bladder

• ________(sacs) in bones, body cavity, and elsewhere

Centralization & Balance

• All locomotor muscles toward body’s _____________…wings controlled by _________ strings

• Gizzard (in lieu of teeth) and other abdominal organs in _______________

Visual Acuity

• ______ eyes

• _______ field of vision

• Remarkable ________ determination

• Brain with enlarged ______ and __________ centers

Respiratory System

• ____________ of fresh air over lung surfaces

• Lungs _________________with each breath (unlike mammals) ________…ensuring lots of incoming O2 and outgoing CO2

• No diaphragm—meaning less weight, too

Rapid Circulation & O2 Carrying Capacity• Increased heart rate• Blood stream O2 carrying capacity greatly

increasedred corpuscles (____________) are _________________ (unlike

mammals)-- more ___________ blood per cubic millimeter

Limited Body Fluids & Excess Weight

• With rapid exchange of air via respiratory system, ____________ needed for cooling

• Highly sensitive diet with _________________ & ____________________ substances

...except for the hoatzin, there are no true ruminating birds. Few species are consistent “grazers” (i.e, year-

round)

Feathers…again

• _________ to birds—no other vertebrates have structure similar to a feather

• Different _____ of feathers for _______________

Feathers: Functions…again…plus…

• Efficient flight

• Thermoregulation

• _______________

• _____________ (some species)

• ____________/mating displays and attraction

Feathers con’t

• Feathers are “_______”

• __________ growths of skin

• Develop from ___________ (like mammal hair)

• _____________ coloration vs. _____________ coloration

From Pettingill 1985 Fig. 20

Feathers con’t

• Feathered areas: ________

• Unfeathered areas: ________

• Counts: __ types __ tracts

• Number: ____ hummingbird ______ tundra swan

Other Coverings

• _______ on bill

• _______ on feet (reptile-like)

• _______ on toes

ALL of these have ______ in skin (aka integument)

Reproduction

• ____________…link to reptiles

• _________________ care…advanced over reptiles

• High potential for ___________a) _______ clutchesb) _______ clutchesc) ___________ capabilities