Zoology - BIRDS

 

THINGS YOU NEED TO KNOW FROM THIS CHAPTER…

  1. Classification of Birds
    1. What phylum do birds belong to?
    2. What class do they belong to?
    3. What are the 2 superorders of birds?

                                                    i.     How are birds in these groups different?

                                                   ii.     What are ratites?

    1. Memorize the 14 orders of birds from your notes and the example birds of those orders.

                                                    i.     I suggest that you make flashcards.  Put the example birds on one side and the order names on the other.  Then start practicing by flipping through them.

  1. Diversity
    1. How many species of birds are there?
    2. What is the hallmark of birds (how can you tell just by looking that they’re birds)?
    3. What are their forelimbs modified as?
    4. What is functionally equivalent to teeth in birds?
    5. Do all birds lay eggs?
    6. List the five adaptations necessary for flight.
  2. What is the significance of the extinct Archaeopteryx lithographica species?
    1. What characteristics do birds have that are like reptiles?
  3. What is the difference between Paleognathae and Neognathae birds?
    1. Which evolved first?
  4. Feather structure
    1. Be able to define and identify on a diagram the following feather structures…

                                                    i.     Quill

                                                   ii.     Rachis

                                                 iii.     Barbs

                                                 iv.     Vane

                                                  v.     Barbules

    1. What does preening do for birs?
    2. What are the functions of the following feathers?

                                                    i.     Contour

                                                   ii.     Down

                                                 iii.     Filoplume

                                                 iv.     Powder-down

    1. What is the feather homologous to?
    2. What is molting?

                                                    i.     How does it usually occur?

                                                   ii.     Are there any exceptions to this?

  1. What are pneumatized bones?
  2. How is a bird skull and skeleton different than a mammal skull?  (HINT:  You should be able to think of numerous examples.)
  3. What is a keel?  Is it found in all birds?
  4. What is the toe-locking mechanism?
  5.   What did ancestral birds primarily eat?
  6.   Do birds eat a lot compared to reptiles?
    1. Finish this statement by adding increases and decreases appropriately to the following blanks…

                                                    i.     As bird weight ______ food consumption ______.

    1. What is the gizzard, crop, and cloaca.
  1.  What is similar between the mammal and bird heart?
    1. What is strikingly different?
    2. Finish this statement by adding increases and decreases appropriately to the following blanks…

                                                    i.     As bird weight ______ heart rate ______.

    1. How are bird red blood cells different than mammals?
  1.   Describe the flow of air through birds.
  2.   What sense is the better developed in birds than in any other animal?
    1. What sense is typically poorly developed?
    2. Are there any exceptions to this?
  3.   How are bird ears and sense of hearing similar to mammals?
  4.   Give 3 examples of birds with phenomenal eyesight.
  5.   What were the driving forces behind the development of flight?
  6.   Defined the following terms related to flight…
    1. Lift
    2. Thrust
    3. Primaries
    4. Secondaries
    5. Downstroke
    6. Powered upstroke
  7.   What type of birds would have the following wings
    1. Elliptical
    2. High-speed
    3. Soaring
    4. High-lift
  8.   Do all birds migrate?
    1. What are the advantages of migration?
    2. What stimulates migration?
    3. How do birds navigate during migration?
  9.   What are 4 advantages of flocking?
  10.   Describe the reproductive systems of male and female birds.
  11.   Are most birds monogamous or polygamous?
    1. Why?
  12.   What is the difference between precocial and altricial birds?
  13.   Give two examples of introduced, pest birds in the U.S.
  14.   What pressures are causing declining bird numbers?

 

CLASSIFICATION OF BIRDS

         

Phylum Chordata

          Class Aves (** Only select orders, listed below, need to be memorized.**)

                    Superorder Paleognathae – Birds with primitive archosaurian

                    palate.  Includes ratites (unkeeled sternum – flightless birds).

                              Order Struthioniformes – ostrich of Africa

                              Order Rheiformes – rheas of South America

                              Order Casuariiformes – cassowaries & emus of Australia &

                              New Guinea

                              Order Apterygiformes – kiwis of New Zealand

Superorder Neognathae – Birds with flexible palate

                              Order Ciconiiformes – storks, vultures, et al.

                              Order Anseriformes – swans, geese, ducks

                              Order Falconiformes – eagles, hawks, falcons, condors, &

                              buzzards

                              Order Galliformes – quail, pheasants, turkeys, domestic

                              fowl, et al.

                              Order Columbiformes – pigeons & doves

                              Order Cuculiformes – roadrunners et al.

                              Order Strigiformes – owls

                              Order Apodiformes – swifts & hummingbirds

                              Order Coraciiformeskingfishers et al.

                              Order Piciformeswoodpeckers et al.

                              Order Passeriformes – perching songbirds

 

I. Diversity

A. Profile

1. Over ______________ species have been described worldwide.

a.  Only __________ have more species among vertebrates.

2. The __________________ is the unique and essential feature or

hallmark of birds.

3. Uniformity in Structure

a. Despite 150 million years of evolution, birds are still

readily recognized.

b. Forelimbs are modified as _______________, although

not all are capable of flight.

c. Hindlimbs are adapted for walking, swimming or perching.

d. All birds have __________________________________.

e. All birds lay _______________.

f. The driving force for this uniformity appears to be the

adaptations necessary for ______________________.

1) Wings are present for support and propulsion.

2) The respiratory system must meet high oxygen

demands and cool the body.

3) Bones must provide a light but rigid airframe.

4) Digestion and circulation must meet the high-

energy demands of flight.

5) And the nervous system must have superb sensory

systems for high-velocity flight.

 

II. Origin and Relationships

A. History

1. The discovery of the fossil of ____________________________

_________________________________ in ­­ linked birds and

____________________________.

a. The skull resembled modern birds but it had ___________

rather than a beak.

b. The skeleton was reptilian with clawed fingers, abdominal

ribs and a long bony tail.

c. Feathers were unmistakably imprinted along the wings.

2. Zoologists had long recognized that birds and reptiles shared

many similarities.

a. Both have skulls that abut the first neck vertebra by a

single __________________________________________.

b. Both have a single middle ear bone, the _____________.

c. The lower jaw in both is composed of five or six bones; in

mammals there is one mandibular bone.

d. Both birds and reptiles excrete nitrogenous wastes as

________________________; mammals excrete urea.

e. Both lay similar yolked eggs; the embryo develops on the

surface by shallow cleavage patterns.

B. Relationships

1. Modern birds include _________________________________

with a flat sternum and __________________________________

with a keeled sternum.

2. _____________________________ has evolved many times

among many bird groups.

3. Smaller birds can revert to flightlessness on islands that lack

terrestrial predators.

4. Larger flightless birds such as the ostrich and emu can outrun

predators.

 

III. Form and Function

A. Feathers

1. Structure

a. The feather is a special bird adaptation that contributes to

more power or less weight.

b. The hollow __________________ emerges from the skin

follicle and continues as a shaft or ____________________.

c. The rachis bears numerous __________________.

d. Up to several hundred barbs are arranged to form a flat,

webbed surface, the _____________________.

e. Each barb resembles a miniature feather; numerous

parallel filaments or ___________________ spread laterally.

f. With up to 600 barbules in each side of a barb, there may

be over one million in the whole feather.

g. Barbules from two neighboring barbs overlap; they “zip”

together with tiny hooks.

h. When separated, they are “zipped” back together by

______________________________.

2. Types of Feathers

a. ________________________ feathers provide the form of

the bird; flight feathers extend off the wing in flight.

b. ___________________ feathers are under contour

feathers; their barbules lack hooks and they function as

insulation.

c. ________________________ feathers are hairlike,

degenerate feathers with a weak shaft and tuft of short

barbs.

d. ________________________________ feathers on

herons and their relatives disintegrate and release a talc-like

powder to waterproof feathers.

3. Origin and Development

a. The bird feather is homologous to the _______________

_______________.

4. _______________________ – most birds molt once a year,

usually in late summer after the nesting season.

a. The fully-grown feather is a dead structure; shedding or

molting is an orderly process.

b. Except in penguins, molting is a gradual process that

avoids leaving bare spots.

c. In many water birds, primary feathers are molted all at

once and the birds are temporarily grounded, usually during

nesting.

B. Skeleton

1. Bone Weight

a. Compared with the Archeopteryx, modern birds have light,

delicate bones laced with air cavities.

b. These are termed _________________________ bones;

they are nevertheless strong.

c. The total weight of a bird’s feathers may outweigh its

skeleton.

2. Bird Skull

a. Bird skulls are so specialized that it is difficult to see the

diapsid condition.

b. The skull is fused into one piece; the braincase and orbits

are large to hold a larger brain and eyes.

c. While the skull is lighter, the legs are heavier than in

mammals; this lowers the _______________________

_____________________.

3. Vertebral Column and Appendages

a. The bird vertebral column is very rigid; vertebrae are

fused except for the cervical vertebrae.

b. Except in flightless birds, the sternum bears a large

_________________ for anchorage of ________________

________________________.

c. Bones in the forelimbs are highly modified for flight, with

some bones reduced in number or fused.

C. Muscular System

1. A _________________________ mechanism prevents a

perching bird from falling off a branch while asleep.

2.  As many as 1,000 muscles may control the tail feathers for

steering in flight.

D. Food, Feeding and Digestion

1. Insect Eaters (______________________________)

a. In their early evolution, birds were carnivorous, primarily

feeding on the great variety of insects.

b. Modern birds have specialized to hunt nearly all types of

insects in most habitats.

2. Other Diets

a. Other animals joined the diet of birds, including worms,

molluscs, crustaceans, fish, frogs, etc.

b. Nearly one-fifth of birds feed on ____________________.

c. The beaks of birds often reveal their food habits and vary

between seed-eaters, insect-eaters, etc.

d. A woodpecker has a straight, hard, chisel-like beak to

expose insect burrows; its long, flexible, barbed tongue

seeks out the insects in the wood galleries.

3. Food Quantity

a. Contrary to the saying “to eat like a bird” meaning “to eat

little,” birds are voracious feeders.

b. Birds have a high metabolic rate and small birds need

even more food per body mass.

c. A hummingbird uses oxygen _______ times faster than a

pigeon and ________ times that of a chicken.

d. A hummingbird eats ________ of its body weight each

day, a blue tit about ________ and a chicken, _________.

e. Because birds lack teeth, foods that require grinding are

cut apart in the ______________________.

          1)  Birds may also swallow pebbles or grit to assist in

grinding in the gizzard.

f.  Many birds have a _______________ that serves to store

food at the lower end of the esophagus.

g. The crop of pigeons, doves and some parrots, also

produces a lipid- and protein-rich “_____________.”

h.  The end of the digestive system is the ______________,

which also receives the products from the genital ducts and

ureters.

E. Circulatory System

1. The ____________________________ heart is large, with

strong ventricular walls.

2. Birds share with mammals a complete separation of respiratory

and systemic circulations.

3. The ____________________________________, instead of the

left as in mammals, leads to the dorsal aorta.

4. The heartbeat is relatively fast compared to mammals and is

inversely proportional to size.

a. A turkey heart beats _______ times per minute.

b. A chicken heart beats _______ times per minute.

c. A small black-capped chickadee heart beats ______ times

per minute.

5. Bird red blood cells (erythrocytes) are nucleated and biconvex.

F. Respiratory System

1. The bird respiratory system differs radically from the lungs of

both reptiles and mammals.

2. Bird Lungs

a. The finest branches of the bronchi do not terminate in

alveoli but are tube-like __________________________.

b. _____________________ extend into the thorax,

abdomen, and even the long bones.

c. A large portion of the air bypasses the lungs and flows

directly to the air sacs on inspiration.

d. On expiration, this oxygenated air flows through the lungs;

therefore there is continuous air flow.

e. Thus it takes __________ respiratory cycles for a single

breath of air to pass through the system.

f. This is the most efficient respiratory system of any

vertebrate.

3. An air sac system helps cool a bird during vigorous exercise

when up to 27 times more heat is produced.

G. Nervous and Sensory Systems

1. A bird’s nervous and sensory system must accommodate the

problems of flight and a visual lifestyle.

2. The bird’s brain has well-developed cerebral hemispheres,

cerebellum, and midbrain tectum.

3. The cerebral cortex, a chief coordinating center in mammals, is

thin, unfissured and poorly developed.

4.  Sense of _______________ is poorly developed except in

flightless birds, ducks and vultures.

5. Birds have good hearing and superb _________________, the

best in the animal kingdom.

6. The bird ear is similar to the ear of mammals.

a. The external ear canal leads to an __________________.

b.  An inner ear has a short _________________; it allows

birds to hear about the same range of sound as humans.

c. Bird ears do not hear as high a frequency as do humans

but surpass us in ability to distinguish differences in pitch

and intensities.

7. The bird eye is similar to the mammal eye but it is relatively

larger for a given body size.

a. A bird eye is less spherical and almost immobile; a bird

turns its head rather than its eyes.

b. Vegetarians must avoid predators and they have eyes

placed to each side to view all directions.

c. Birds of prey have eyes directed forward to provide better

depth perception.

d. A hawk has eight times the visual ________________ of

a human and can see a rabbit over a kilometer away.

e. An owl’s ability to see in dim light is more than

_________________ that of a human.

f. Many birds can see partially into the

____________________________ spectrum, seeing flower

nectar guides.

I. Flight

1. History

a. The early airspace was an unexploited habitat with flying

insects for food.

b. Flight also provided rapid escape from predators and

ability to travel to better environments.

c. There are two hypotheses on the evolution of bird flight.

          1)  Ground up

          2)  Tree down

d. Feathers preceded flight and arose for thermoregulatory

purposes.

2. Flapping Flight

a. Flapping flight requires a vertical ___________________

force and a horizontal ________________________ force.

b. Thrust is provided by ___________________ at the wing

tips and lift is provided by the ___________________.

c. Greatest power is provided by the

___________________.

d. The _______________________________ is essential

for hovering and fast, steep takeoffs.

3. Basic Forms of Bird Wings

a. ___________________ Wings

1) Birds that must maneuver in

______________________________________

have elliptical wings.

2) Elliptical wings are slotted between primary

feathers to prevent stalling at low speeds, etc.

3) The small chickadee can change its course within

0.03 seconds.

b. ___________________ Wings

1) Birds that feed on the wing or make

______________________________________ have

high-speed wings.

2) These wings sweep back and taper to a slender tip;

this reduces “tip vortex” turbulence.

3) They are flat in section and lack wing-tip slotting.

c. ___________________ Wings

1) Albatrosses, gannets and other oceanic soaring

birds have wings with long, narrow wings.

2) The high-aspect ratio of long, narrow wings lack

wing slots and allow high speed, high lift and dynamic

soaring.

3) They have the highest aerodynamic efficiency of

any design, but are less maneuverable.

4) These birds exploit the highly reliable sea winds,

and air currents of different velocities.

d. ___________________ Wings

1) Vultures, hawks, eagles, owls and other

______________________________________ that

carry heavy loads have wings with slotting, alulas and

pronounced camber.

2) This produces high lift at slow speed.

3) Many are land soarers; their broad, slotted wings

allow sensitive response for static soaring.

 

IV. Migration and Navigation

A. Migration

1. About ______________ of all bird species migrate.

2. They can move between southern wintering regions and northern

summer breeding regions.

3. They can exploit seasonal changes in abundance of insects and

avoid bird predators.

4. Appearing one time a year prevents buildup of specialized

predators.

B. Stimulus for Migration

1. The long days of late winter and early spring stimulate

development of gonads and fat.

2. Long day length stimulates the anterior lobe of the pituitary.

3. Release of pituitary gonadotropic hormone sets in motion a

complex series of physiological and behavioral changes resulting in

gonadal growth, fat deposition, migration, courtship, mating

behavior and care of young.

C. Direction Finding in Migration

1. Experiments suggest birds navigate chiefly by

___________________.

2. Birds recognize topographical ___________________ and follow

familiar migratory routes.

3. This pools navigational resources and also experience of older

birds.

4. Birds also have a highly accurate innate sense of time and an

innate sense of direction.

5. Research indicates they can navigate by the

______________________________________; this may be

related to magnetite found in the neck musculature of pigeons.

6. Sun-azimuth Orientation

a. German ornithologists used special cages to show birds

navigate by sun at day and stars at night.

b. Planetarium experiments revealed they use the

___________________ as a compass; an internal clock

tracks position.

c. These experiments suggest use of the ______________

___________________ as an axis at night.

 

V. Social Behavior and Reproduction

A. Cooperative Behavior

1. Sea birds often gather in huge colonies to nest and to rear

young.

2. Birds that isolate during breeding may congregate for migration

or feeding.

3. There are many advantages for flocking together:

a. mutual ___________________ from enemies

b. greater ease in finding ___________________

c. less opportunity for an individual ___________________

during migration

d. mass ___________________ for protection against low

night temperatures during migration.

B. Reproductive System

1. Bird testes are very small until the approach of the breeding

season, when they may enlarge 300 times.

2. Males of most species lack a penis; mating involves bringing

cloacal surfaces in contact known as _______________________.

3. In most birds, the ___________________ ovary and oviduct

develop and the right ovary and oviduct degenerate.

4. The expanded end of the oviduct, the ___________________,

receives the discharged eggs.

5. Special glands add ___________________ or egg white to the

egg as it passes down the oviduct.

6. Farther down the oviduct, the shell membrane, shell, and shell

pigments are also secreted.

7. Fertilization must therefore take place in the upper oviduct before

albumin and shell are added.

8. Sperm remain alive in the oviduct for many days after a single

mating.

C. Mating Systems

1. Over 90% of bird species are ________________________;

they only mate with one partner each breeding season.

2. A smaller number are ___________________; individuals mate

with two or more partners each breeding season.

3. The reason birds have a high monogamy rate, compared to

mammals, is two-fold…

a.  Baby birds lack a built-in food supply and require

the parental care from both parents to provision the young.

b.  Bird Territories

1) A male sings often to announce his presence to

females and drive away males.

2) Females wander about to select a male that offers

the best chance of reproductive success.

3) Usually a male can defend an area that provides

just enough resources for one nesting female.

D. Nesting and Care of Young

1. Nearly all birds lay eggs that must be incubated by one or both

parents.

2. ___________________ birds are able to feed and run or swim

as soon as they are hatched.

3. ___________________ birds are naked and helpless at birth

and must be fed in the nest for a week or more.

4. Nesting success in altricial birds is very low; sometimes barely

20% of nests produce young.

5. Causes of nesting failure include predators, nest parasites and

other factors.

 

VI. Bird Populations

A. Factors

1. Humans have introduced birds to new regions; the

___________________ and the ___________________________

are both abundant now in the United States.

2. Since the dodo went extinct in 1695, more than ______ bird

species have also become extinct due to human influence.

3. Causes of bird extinction include ________________________

____________________ and ___________________.

4. Modern hunting interests have helped recover wetlands; no

legally hunted birds are endangered.

5. Recent Decline of Songbirds

a. Some songbird species that were abundant 40 years ago

are in decline.

b. ___________________ has utilized once-fallow fields.

c. ___________________ of forests in the United States

exposes nests to nest predators.

d. __________________________ are formidable predators

that kill many songbirds.

e. The loss of tropical forests also deprives about 250

migratory songbirds of their wintering homes.