volume 7, Number |

January/February 1978

Contents

3A Birdis...

6 Migration

12 Courtship

16 Bird Song

19 Coloration

22 Birds of Prey

25 Zoo Management

28 Conservation

31 A Bird Bibliography

Front Cover: To fly is the glory of birds,

nature’s perfect flying machine.

Back Cover: Feathered tapestry at its bril-

liant best is displayed in a peacock’s shim-

mering plumage.

Design-Production:

Monica Johansen Morgan

Copy Editor:

Mary Massey

Photographs on page 12 and back cour-

tesy of Smithsonian Institution, Office of

Photographic Services; p. 16 by Deb Mayer;

p. 16 courtesy of Bureau of Sport Fisheries

and Wildlife by Jack Dermid; p. 20 by Tom

Jones; all others by Francie Schroeder;

ilustration on p. 7 by Ben Butterfield; on

p.13 by Susan Hughes.

Friends

of

the

National

is anon-profit organization of individuals and

families who are interested in supporting Zoo

education, research, and conservation.

As a FONZ, you and your family receive

FONZ Board of Directors 1977-78

Stephen T. Hosmer, President

John S. Brown, First Vice President

Nancy Porter, Second Vice President

M. Anthony Gould, Treasurer

Victor Delano, Secretary

Nella Manes

Cecil McLelland

Sheila D. Minor

Robert L. Nelson

Peter C. Andrews

Theodore Babbitt

Edward G. Boehm

Janice A. Booker

Montgomery S. Bradley —_ John B. Oliver

Timothy V.A. Dillon Whayne Quin

Ronald J. Field Ross Simons

Donna Grosvenor Julia V. Taft

Julie P. Hubbard Lee Talbot

Sally S. Tongren

FONZ Staff

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hat is a bird? By definition,

Wi: is a warm-blooded, feath-

ered vertebrate. By analogy, it is

a perfect flying machine. Senti-

mentally, it is a little feathered

friend. Jonathan Livingston Sea-

gull explained that he was

“not bone and feather, but

the perfect idea of freedom and

flight... limited by nothing at

all.” Birds evoke many images.

A bird is flight. It is the wander-

ing albatross, circumnavigating

the globe on 11-foot wings. It is

the peregrine falcon in a 175-mph

power drive. It is the ruby-

throated hummingbird, less than

an ounce of organized _ proto-

plasm, flying 500 miles across the

Gulf of Mexico. It is the osprey

seizing a fish in a flash of spray.

A bird is an egg—three pounds

worth for an ostrich, pea sized

for a hummingbird. It is round

owl’s eggs, nested in a hollow

tree, or pointed murre’s eggs,

spinning on a rocky shelf. It is the

spotted eggs of the plover and the

tinamou’s turquoise china eggs.

A bird is feet— paddling webs on

ducks, frogmen’s flippers on

swans. It is the stout toes of

pheasants, scratching in the dust,

Air-curved feathers and lifted wings power

this silver gull at take-off.

or the long, slender toes of the

jacana, tiptoeing across lily pads.

A bird’s foot is quail tracks in the

snow and sandpiper tracks across

the beach.

A bird is voice. It is the wild

chorus of loons before a storm. It

is the thrush in the last summer

daylight, or a chickadee’s first,

tentative “phoebe” call in Feb-

ruary. It is the booming of the

emu, the shrieking of the sea

eagle, the laugh of the kooka-

burra, and the courtship scream

of the argus pheasant.

A bird is color. It is a scarlet

cardinal in the snow or the me-

tallic flash of a hummingbird in

the petunias. It is a hyacinth

macaw, a strutting peacock, and

a flamingo. It is the startling crim-

son flash of the turaco’s wing.

A bird is design. It is the com-

plex structure of a feather. It is an

elegantly adapted skeleton with

hollow bones trussed like indus-

trial girders. It is lungs that pro-

vide efficient air cooling. It is the

hawk’s eyes with six times the

range of the human eye. It is the

stereo reception of owls’ ears and

the soaring wings of vultures.

A bird is vital—an active partici-

pant of its environment. It is a

spreader of seeds and a pollinator

of flowers. It is a swan clearing a

4

Ever-alert ears provide stereo reception to enhance the hunting skills of this Malay fish owl.

pond of weeds, and a duck

carrying pond weeds from one

lake to another on its feet. It is an

eater of insects and a controller

of mice. It is the kookaburra that

eats snakes in an Australian gar-

den or a grouse being eaten by a

fox in the Arctic winter. Once it

was a dodo, in whose gizzard

seeds were abraded until the

seedling could split the shell, but

that was long ago.

A. bird

is excitement. It is the

gleam of a bald eagle high above,

head and tail brilliant white in the

sun. It is the flight of Canada

geese calling each other as they

make their landing. It is the

muted glory of the argus pheas-

ant’s display. It is the wild court-

ship ballet of the cranes and the

graceful, neck-twining courtship

of the swans. It is a newly

hatched kiwi.

A bird is competence. It is the

emperor penguin cradling his egg

on his feet for two months of the

Antarctic night. It is migratory

warblers, voices in the night as

they travel south. It is a flock of

juncos, nestled safely in a snow-

covered bush. It is sand grouse,

soaking up water in their feathers

to carry to their brood.

A bird is myth and legend. It is the

eagle of Jove and the owl of

Athena, Juno’s peacock and

Odin’s raven. Leda had a swan

and so did Lohengrin. The

Egyptians had the god Thoth with

the head of an ibis and Horus

with the head of a hawk. Pre-

historic man carved an owl in his

cave; American Indians worship-

ped the thunderbird. Birds are

deep in our past.

A bird is a symbol. There were

eagles on the Roman standard

and hawks in heraldry. Hawks

and doves fly down the halls of

the Capitol.

We are “proud as peacocks” and

“happy as larks’” and “welcome

as the robins in spring.” A wild

goose embodies both an act of

futility and an untamed spirit.

A bird is a long, lonely flight into

the dark. It is a vanished flock of

passenger pigeons and Carolina

parakeets. But it is sometimes a

flight into a new dawn. It is

trumpeter swans again on an

Graceful grazers of aquatic pastures, the Zoo’s black swans search their pond for edible

grasses.

Idaho lake and a family of nene

geese on Haleakela. It is 105

whooping cranes where there

were but 14. It is hope for the

future if we learn to understand

and respect the present. CJ

by Sally Tongren

FONZ House Guide

Migration

_.. said the second swallow,

“First, we feel it stirring with-

in us, a sweet unrest; then

back come the_ recollec-

tions, one by one... .”

“Ah, yes, the call of the

South, the South!” twit-

tered the other two dream-

ily... .” And do you think,”

said the first swallow, “that

the other call is not for us

too, in its due season? The

call of lush meadowgrass,

wet orchards, warm insect-

haunted ponds... and_ all

the farm buildings clustering

round the House of the per-

fect Eaves?”

The Wind in the Willows

by Kenneth Grahame

igration has always stirred

M man’s imagination. We feel

that if migratory birds did talk,

they would sound like the swal-

lows, expressing a longing that

pulled them toward remembered

scenes. And, for all the study

which has been devoted to it,

there is still much about migra-

tion that we do _ not. fully

understand.

Migrating mallards blacken the sky as “in-

ternal clocks” send them commuting in

mass from winter to summer homes.

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| Feathers distinguish birds, as a class, from other vertebrates. Light in weight, yet surprisingly strong, they insulate, waterproof, and

streamline a bird as well as enable flight. A typical feather consists of a strong central shaft off which emerge a series of parallel barbs.

The barbs, in turn, branch into tiny parallel barbules which carry either microscopic hooks or flanges. These lock the barbs to forma

tight, flexible surface. Down feathers, found on many baby birds and some adults, have no central shaft or barbules, but are unsur-

passed as insulation.

' Feathers are adapted for special purposes. Flightless birds, such as the rhea and emu, lack barbules, so their feathers look hairy, yet shed

| water and provide warmth. Many birds have ornamental plumes that play a part in courtship or as recognition marks. Others, like the

kiwi and frogmouth, have feather bristles around the mouth that transmit touch. The owl and ostrich have feather eyelashes.

. The outer, or primary, feathers of the wing do most of the work in flight. Without these, the bird cannot fly. To glide and soar, a bird

¥ makes use of moving air and the excellent aerodynamic design of the wing for a type of flight that uses very little energy. All birds

glide at times, but sea birds such as the albatross may spend most of their lives soaring over the sea, coming to land only to breed.

The flapping flight of robins or crows uses more energy but permits fast changes in direction. Power is provided by the forward and

down stroke of the wing, driven by the large flight muscles of the breast. On the return stroke, the wing is half folded, and the primary

feathers open like venetian blind slats to reduce air resistance.

We do not know why birds

started to migrate. Undoubtedly

it had to do with climatic changes

over long periods of time. We do

know that birds are still chang-

ing their migration and distribu-

tion patterns. Some are extending

their ranges north; others have

appeared and settled down in

another hemisphere. After all,

they are mobile— they can fly!

From the practical point of view,

it would be surprising if birds did

not migrate. The ecological ad-

vantages of migration far out-

weigh the dangers of the long

trips. Birds migrate because it is

to their advantage to do so. But

there are variations even within a

species. Fox sparrows around

Puget Sound are non-migratory,

but the races that breed farther

north do migrate. The farther

north they breed, the farther they

migrate: the Alaskan populations

winter in California, while the

birds from British Columbia win-

ter in Washington. Different eco-

logical conditions have induced

different patterns of migration,

and these have become fixed.

A rich array of plumage sets apart the Mandarin duck. Native to the Far East, these dis-

tinctive waterfowl are losing their forest, pond, and stream habitat to modern forestry

management.

What are the advantages of mi-

gration? If you visit one of the

Chesapeake Bay refuges in the

winter, you will realize that there

is nO way so many waterfowl

could find space to nest or

enough food for their young if

they stayed there in the breed-

ing season. Whistling swans are

there by thousands, but in the

spring those swans will spread

over the Arctic tundra so that

there are only one or two pairs

per square mile. North-bound mi-

grants move into a world where,

because of the severe winters,

there are almost no resident birds.

Only five out of sixty-four species

remain in northern Greenland

over the winter. Even in as mild a

climate as that of England, about

thirty percent of the nesting birds

are migrants.

However bleak the winter cli-

mate, food and nest sites abound

in the northern summer. The long

days allow maximum time for the

parents to forage for their grow-

ing young. Because the nesting

period is short, only a few weeks

in the high Arctic, and the pop-

ulation dramatically increased,

there are a tremendous number

of young birds present for a short

time. Predators, including migra-

tory hawks and skuas, may grow

fat during this period, but they do

not seriously affect the bird popu-

lation. In fact, predation in the

Arctic is much less severe than it

is for birds in the tropics.

The whys of migration are clear

when one sees the advantages,

but the hows remain complex.

How do birds know when to start

north and when to leave in the

fall2 How do the swans find their

way from the Chesapeake Bay to

the Mackenzie Bay Delta? How

does the blue-winged teal navi-

gate from Canada to Chile?

Generalization about migration is

dangerous, since not all birds

follow the same pattern. Usually

migration is a part of the bird’s

Whistling swans find winter haven and grain-filled fields along the Eastern Shore of Maryland.

breeding cycle and is governed by

an internal mechanism, or

“clock.” Changes in day length

trigger activity of the pituitary

and thyroid glands. This starts de-

velopment of the sex organs,

which in turn. secrete other

hormones. Many birds molt into

breeding plumage, and all ac-

cumulate a layer of fat as fuel for

the trip. There is a general rest-

lessness among the birds. Favor-

able weather, such as a warm,

southerly wind in spring, is the

final cue to fly north.

A similar sequence governs fall

migration. The sex organs shrink,

there is often a post-nuptial molt,

and as the days grow shorter, the

birds fatten for their trip. Again, it

is often weather conditions that

send them south, this time on a

north wind.

What about birds that winter in

the tropics where day length is

about the same all year, or those

that winter south of the equator

where the days grow shorter in

March and April? What. starts

their body changes and triggers

migration?é No one knows for

certain. There may be cues in the

local environment that we do not

understand, or it may be that

their internal “clock” was set the

preceding fall to go off in the

spring. Different populations of

the same species start north at

different times, depending on the

arrival of spring at their

destination. Tropical birds have

their own patterns of movement,

usually in response to rainfall and

availability of food. For instance,

Australian grey teal move rapidly

into flooded areas, taking advan-

tage of a scarce and temporary re-

source in order to nest and raise

their young. Their breeding cycle

and migrations are governed by

rain, regardless of season.

Spring migration usually proceeds

at a steady pace. Spring storms

may delay the traveling flocks,

but they pick up speed once the

weather is right. Certain con-

ditions, such as open water in the

case of waterfowl, are required

before it is safe to arrive on the

breeding grounds. Canada geese

follow closely the advance of the

32-degree isotherm, which assures

open ponds and rivers. Other

Species seem to wait for warm

weather and then make a fast

through trip. Rarely is the arrival

of migrating birds as regular as

the swallows at Capistrano, but it

usually falls within a predictable

few days.

In fall, migration is more lei-

surely. Young birds of many spec-

10

ies wander extensively. Adult

ducks molt all their flight feath-

ers at one time and take molt mi-

grations to sheltered marshes or

bays where they can spend the

three- to four-week _ flightless

period in safety. Meanwhile, the

young of the year wander far

afield. Shelducks from all around

northern Europe migrate to the

island of Heligoland in the Baltic

at this time, returning after the

molt to their native beaches.

Some birds start south almost be-

fore the summer has begun. Sand-

pipers, possibly those that were

unsuccessful in nesting, appear in

New England in July still in breed-

ing plumage. They may feed

along the beaches for several

months. Male ruby-throated hum-

mingbirds depart as early as July,

leaving the females to raise the

broods. Many warblers start south

while the weather is still good and

the food abundant. Blue-winged

teal go south in September, but

mallards may stay until snow

falls, or even through the win-

ter if there is open water. Many

water birds only move from fresh

to salt water. Each species has its

own pattern, which is part of its

breeding cycle.

There are many different ways of

migrating. Waterfowl travel by

day or night. They must have

water to land, and they prob-

ably travel from one good stop-

ping place to the next. These may

become traditional stops, since

waterfowl travel in family groups

or flocks of mixed ages and the

young birds are able to learn the

routes. Many of the small song-

birds travel at night, giving them a

chance to feed during the day.

Hawks usually travel by day, as

do storks and cranes. All these

birds ride rising air currents to

help them along. They avoid

traveling over large bodies of

water where few thermals exist.

Birds may travel in flocks or solo.

Flocks offer protection from

predators and the advantage,

sometimes, of experienced

travelers for guidance. Flocks

may be all adult or all immature

birds: they may be all males or

mixed females and young or all

ages and sexes. There may be

only one species in a flock or

several. Geese and swans travel in

family groups or flocks made up

of several families. The familiar

V-shape of these flocks is an

energy saver; each bird slightly

reduces the wind resistance for

the bird behind. Birds sometimes

change places in the formation.

Birds may follow one route going

south and another coming north.

The golden plover flies south di-

rectly across the ocean from

Newfoundland to a landfall in

South America on its way to

Argentina. It returns by way of

Panama, across the Gulf of Mex-

ico, and up the Mississippi. In the

fall, Newfoundland has plenty of

food to fatten a bird for a long

trip, but in April it is still bound in

ice and fog. The Arctic tern mi-

grates to the Antarctic down the

coast of Africa from its Canadian

nesting grounds, but returns up

the South American coast. This

allows it to take advantage of

favorable wind patterns.

Distances traveled, speeds, and

heights vary. Lesser snow geese

wintering on the Gulf of Mexi-

co may cover the 1,700 miles

from Canada to Louisiana, non-

stop, In 60 hours. Ducks may

travel down the Mississippi fly-

way in massive flocks known as

a “grand passage.” One group left

Saskatchewan on October 23 and

24 and arrived in Louisiana on

October 24 and 25. This is a trip

of about 2,400 miles at about 48

mph. Most birds probably aver-

age around 35 mph. Most fly

fairly low, 5,000 feet or less. Some

will climb higher to get above

clouds. The record is 21,000 feet.

How do birds find their way? Ex-

periments indicate that birds can

navigate by the sun and stars. A

captive bird in the restless state

that precedes migration will hop

around its cage. If it can see the

sky, most of its movements will

be in a fixed direction, north in

spring and south in fall. If it can-

not see the sky, its movements are

random. Feeding flocks can be

seen taking short flights, almost

always in the direction of their

destination. Experiments in plan-

etariums show that some birds

have an innate orientation to

star patterns. Many birds will

not fly in overcast weather, al-

though some will gain altitude un-

til they are above the clouds.

Others, including ducks, seem to

be able to take their direction

from the wind. Wave patterns

may give directional clues to

oversea travelers, and probably

some birds use landmarks—

rivers, mountain ranges, clouds

that form over islands. Probably

most species use a combination

of these methods.

The more we learn about mi-

gration, the more complex it be-

comes. The next time you see a

tiny hummingbird buzzing in a

petunia bed, consider that it can

fly the Gulf of Mexico—non-

stop. It’s food for thought. cq

by Sally Tongren

FONZ House Guide

Allin a line, these lesser white-fronted

geese swim Zoo waters in search of aquatic

plant food.

12

he Zoo’s male wattled curas-

sow bends his long neck back-

ward and rests his head on his

shoulders. He lifts his stiff back

tail, revealing snowy white

feathers. In this awkward pose he

circles around the female again

and again. Sometimes he pauses

to pick up small pebbles or other

objects and holds them briefly in

his bill.

This curious performance of the

wattled curassow is called a

courtship display. It is only one of

thousands of elaborate court-

ship rituals used by birds. It may

seem puzzling at first that birds

should have evolved so many

complex courtship behaviors.

After all, comparable displays are

seldom found in either mammals

or reptiles.

Part of the explanation is that

birds are highly visually oriented.

The evolution of flight required

the evolution of keen eyesight.

Unlike most reptiles and mam-

mals, birds can see colors. Most

of their courtship displays use

brightly colored feather patterns,

raised crest feathers, or unusual

postures by the male. All such

elements appeal to the sense of

sight.

The fanning display of an Indian peacock

is just one of many colorful courtship

rituals used by birds to attract the atten-

tion of potential mates.

The wattled curassow, for in-

stance, has lobes or “wattles” of

bright red-orange flesh above and

below his bill. When he rests his

head on his shoulders, the bright

orange of the wattles contrasts

sharply with his black body

plumage. Lifting his tail to re-

veal the white features also

creates a strong visual contrast.

Charles Darwin was the first sci-

entist who tried to explain the

great variety of bird courtship dis-

plays. He believed that court-

ship displays evolved gradual-

ly over thousands if not millions

of years. If a male performed a

simple courtship display and was

able to attract and mate with

more females than males that did

not display, he theorized, then

the displaying male would leave

more descendants in the next gen-

eration. These descendants would

presumably also display, and so

the display would gradually

spread through the entire popula-

tion. Similarly, the display might

later become more and more

elaborate. Also, the males might

evolve feather colors, crests, or

other adornments that would

serve to improve the display.

Most scientists accept Darwin’s

principle of sexual selection. But

in light of our modern know-

ledge of genetics, we can add sev-

eral points that did not occur to

Darwin. First of all, Darwin never

really explained why the female

should choose a male that dis-

plays elaborately over a male

whose display is more simple.

Scientists now believe that, in the

long run, females choose the

fittest partners. In pairing with a

highly fit male, a female ensures

that her offspring will be fit. Thus

she guarantees that her own

genes are perpetuated in future

generations. A male’s courtship

display may provide females with

a great deal of information about

his overall fitness.

For instance, the male wattled

Curassow must circle the female

repeatedly before she will mate.

A weak bird may give up be-

fore the female responds. Court-

ship involves even more stren-

uous performances in many other

species. In addition, the very bril-

liance and elaborateness of the

male’s plumage can provide an

indication of his fitness. Just con-

sider how much of a peacock’s

food energy must be diverted for

him to grow and maintain such

long and intricately colored

plumes. Yet his plumes are use-

less except in courtship.

Courting cranes will “dance” by hopping on one foot and then the other as part of their

mating game.

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All courtship displays, from the

simplest to the most spectacular,

play another important role that

did not occur to Darwin. Court-

ship keeps species separate and

prevents their interbreeding.

Thus, a female wattled curassow

is genetically programmed to re-

spond only to the display of a

male wattled curassow and not to

the display of a related species.

A male’s coloration can signal his

species. So, in courtship the male

will often prominently display his

markings as his species’ unique

badge. The wattled curassow and

some of its close relatives pro-

vide a particularly striking illustra-

tion of this.

Inhabiting the rain forests of west-

central South America, the

wattled curassow occasionally

encounters members of four

other closely related species of

curassow. Yet the species appar-

ently do not interbreed. Probably

the coloration of the males pre-

vents It.

The distinguishing marks of many

birds are far more extensive than

those of the curassows. Most

male pheasants, for example,

have a brilliantly colored and dis-

Neck-bending, circling, and fanning white

tail feathers are all part of the carefully

orchestrated courtship display used by

the Zoo’s wattled curassow.

tinctive “uniform.” Female pheas-

ants are usually dull brown with

few distinguishing marks. The

typical male pheasant is probably

unable to distinguish a female of

his own species from a female of

a closely related species. Inter-

breeding is prevented because the

distinctive males are easily re-

cognized by the females.

The Zoo’s courting golden pheas-

ant cock displays all of his multi-

colored plumage. First he stands

at an oblique angle to the hen,

then expands his orange and

brown neck feathers to form a

“ruff” so wide it conceals most of

his head. He tilts his body toward

the female and fans out the blue

and black feathers of his mid-

back, the golden feathers of his

rump, and his long, mottled tail

plumes. The cock holds his pose

only briefly. Then he circles

around the female, chortling ex-

citedly. This circling may con-

tinue for an hour or more. From

time to time, the male stops cir-

cling and displays his plumage

again. At each stop, the male

catches the female’s attention

with a cat-like hiss.

Perhaps the most spectacular

pheasant courtship is that of the

great argus pheasant, another

species on exhibit at the Zoo. In

its natural habitat, each adult

male argus pheasant has his own

displaying ground on a level spot

in the forest. This display court, or

“arena,” is eight to ten yards in

diameter, and the resident male

carefully clears it of weeds and

debris. Usually several display

courts are found clustered in one

area, fifty to one hundred yards

apart. The sites may be used for

several generations. The naturalist

William Beebe wrote of a dis-

play court in Borneo: “An old

Dyak chief led me to this arena

and told me that his father had

trapped many argus in it, and no

one knew when there was not an

arena there.”

The male maintains his court for

at least six months of the year.

While there, he begins calling at

dusk every day and continues

through the night. His ‘“how-ow”

call can carry over a mile and

lures females. When a female

arrives at the court, the male

stalks around her with his neck

strained forward. His feet make a

tapping sound on the ground.

Next he spreads his wings to form

a wide circle around his bald,

blue head. He holds this pose

briefly, then jumps suddenly, vi-

brating his wings and long tail

plumes. Both his wing and tail

plumes are covered with silvery

spots, so shaded that they appear

to be three-dimensional beads.

Because of these markings, this

species has been named for

Argus, the many-eyed monster of

Greek mythology.

Each phase of a bird’s colorful

courtship—whether it be the

foot-tapping of argus pheasants

or the circling techniques of

wattled curassows—thus forges a

link in the chain of behavior de-

signed for just one reason—the

propagation of species. O

by Austin Hughes

The Zoo’s great argus pheasant lives up to its name by performing perhaps the greatest of all mating rituals that combines calls, foot

tapping, and fanned, vibrating wings. The rituals are performed in special “arenas” in the forest.

Sure sign of spring, a robin readies a worm meal for its hungry young. The spotted breasts of the juveniles indicate their kinship to other

thrushes.

pring means bird song. The ob-

servers of old assumed that,

like human song, bird song ex-

pressed love, joy, or some other

emotion. Today scientists say

birds sing to defend territory.

In spring an adult male robin—to

take a typical example—stakes

out his personal territory. His

“home” may be a half-acre of

suburban lawn from which he will

chase off other trespassing males.

Cock robin advertises his pre-

16

sence and his ownership of the

territory by singing from a con-

spicuous perch within. Also, if a

male does not yet have a mate,

his song can attract passing fe-

males to his territory. Staking out

a claim and protecting it are im-

portant because food for the

young will have to be found with-

in that territory.

Songbirds are found in only one

order of birds—the passerines or

perching birds—but this order

contains three-fifths of all bird

species. Passerines include most

of our familiar native birds, such

as the robin, cardinal, mocking-

bird, and song sparrow. The Zoo’s

Bird House displays exotic song-

birds from all parts of the world,

such as the Napoleon weaver, the

yellow-breasted starling, and the

vermillion cardinal.

Birds make other vocal sounds

besides song. Walk through a

wooded area on a summer after-

noon, and you will hear another

bird sound—alarm calls. As you

proceed, your arrival is announ-

ced by short, explosive chirps.

Not only songbirds give alarm

calls. The howling alarm calls of

seagulls are familiar to every

seaside stroller.

Still other bird sounds are used. A

mother quail or pheasant uses a

special call to point out food to

her chicks. During courtship, a fe-

male cowbird sounds a specific

note when she is ready to copu-

late. Baby birds of many species

beg for food with loud cheeps.

Since birds use sound to com-

municate, it is not surprising that

scientists have studied the ways

bird sounds resemble human lan-

guage. A human child must learn

a language in order to communi-

cate with other humans. Do birds

also have to learn their songs and

other calls?

A simple experiment can shed

light on this question. A scientist

can take an egg from a song

sparrow nest, for instance, hatch

the egg in an incubator, and

hand-raise the bird in complete

isolation from other song spar-

rows. Such a song sparrow

can still give the typical alarm

calls of the species. But if the bird

is a male, he will never be able to

sing the song sparrow’s typical

song. When he matures, he will

produce various erratic whistles

but nothing like the song spar-

row’s distinctive song. So we have

found that some bird sounds are

innate and some must be learned.

An experienced bird-watcher

from the east coast visiting the

midwest for the first time may

find that many songbirds sound

slightly different from those at

home. Scientists confirm that

there are local dialects. A re-

gional dialect may help a return-

ing migrant bird recognize that he

is nearing home.

Scientists have also found that

each bird’s song is unique. All

song sparrows sound like song

sparrows—to ornithologists and

presumably to each other. But

each song is subtly indivi-

dualized and so like no other.

Male birds may use these differ-

ences to recognize neighboring

males as individuals. The human

ear usually cannot detect such

differences, but they show up

clearly in spectograms— “pictures”

of bird song produced by a sono-

graph machine.

Birds produce vocal sounds dif-

ferently than mammals. A

mammal has vocal cords in the

larynx or upper part of the throat.

A bird’s larynx has no vocal cords.

Instead, sound is produced by the

within the bird’s chest where the

two bronchial passages unite to

form the windpipe.

Since song helps birds recognize

members of their own species, it

is not surprising that each of the

more than 500 different songbirds

Songbirds, like the red-billed blue magpie,

sound off to defend territory, signal alarm,

and attract mates. Magpies can also “talk”

by imitating human voices.

7

has a distinctive song. Some

songs sound harsh and unmusical

to human ears. The beautiful

golden-breasted starling sounds

as harsh and grating as his drab

cousin, the common starling. Nat-

uralists say the “best” singers—

those whose songs sound the

most musical to our ears—are

usually drab birds. The grayish

mockingbird—frequently called

the world’s “‘best’”” singer — comes

immediately to mind.

The National Zoo’s Dr. Eugene S.

Morton has conducted research

to learn why different species

have evolved diverse songs.

Working in Panama, he found

that forest birds tended to have

relatively low-pitched songs,

while grassland birds had a wider

range of pitch. The forest vegeta-

tion, he discovered, quickly

blocks out high-pitched sounds.

Thus, the forest birds use a song

that travels farthest in their parti-

cular habitat. The grassland birds

can use higher frequencies since

nothing in their habitat inter-

feres with these frequencies.

Harbinger of spring and delight to

human ears, bird song is, in fact, a

vital language used by feathered

creatures to stake out territory,

attract females, signal alarm, and

much, much more. O

by Austin Hughes

Spectograms that graph bird sound help the Zoo’s Dr. Eugene Morton learn why different species sing different songs.

irds as a class are the most

colorful of the vertebrates.

Perhaps only an animal that can

quickly fly from danger can

afford to be so conspicuous.

Taken as a group, the Psittaci-

formes—parrots, macaws, cock-

atoos, lorys, and parakeets—

are among the gaudiest birds.

Kept as cage birds for centuries,

they tame readily, and many can

be taught to talk. Sad to say,

parrots have no idea what they

are saying. They simply mimic. In

the wild they communicate with

loud, rather harsh cries that carry

through the thick treetops where

many of these birds live.

The Psittaciformes are wide-

spread through thetropics:

Central and South America,

Africa, Southeast Asia, and the

Malay-Australian region. They are

large headed, short necked, and

usually brightly colored. They

have strong hooked bills and a

prominent hump or cere on top of

the bill through which the nostrils

open. All have four toes, two

pointing forward and two back,

giving them a powerful grip. Psit-

tacines use these powerful feet

and often their bills to climb

through the branches. They ofter

pick up food in one foot and eat

The gaudy scarlet macaw belongs toa

colorful class of birds called Psittaciformes

that includes parrots, cockatoos, and par-

akeets.

Zoo-installed wire mesh provides support for stick nests built by the resident colony of

scarlet ibis.

it as we eat a sandwich. They fly

strongly, but not for long dis-

tances. Their broad rounded

wings are well suited to maneuver

through close-placed branches in

the forest. Most psittacines nest

in holes.

Usually male and female psitta-

cines have the same coloring, but

the male and female of one spe-

cies, the eclectus, are so different

20

that they were long considered to

be two different species. The

male eclectus is green with crim-

son wing linings, and the female

is crimson with blue markings.

Australia and New Zealand boast

a number of atypical parrots—

nocturnal forms, ground-nesting

forms, and the flightless kakapo

in New Zealand. Many of these

live in grassland areas and have

predominently brown and olive

green plumage.

How can brilliantly colored birds

survive without the marvelous

protective coloring of so many

other species? If you study the

woodcock or the hen pheasants in

the Bird House, it is clear that

these birds are well hidden when

they hunt for worms in the dead

leaves or nest on the ground.

Birds of open fields and shores,

like sparrows and sandpipers,

need protective, or cryptic,

coloring for concealment. But

parrots and other brilliant tropical

birds are actually far less con-

spicuous than one might think. In

the intense light, flashing green

foliage, and colorful flowers of

the high tree tops, the greens,

reds, and blues blend rather than

stand out. Flashes of color, such

as red wing patches, help them

keep in touch with each other

among the thick leaves. Even

among birds that are cryptically

colored, such as shore birds, there

are often white tail feathers and

wing patches that appear to serve

as signals to the other members of

the flock. Although color seems

to be related to the bird’s habitat

and serve as protection, there is

much still to be learned about

this. There appears to be a con-

nection between a warm, humid

climate and the intensity of color.

Whether this is related to humidi-

ty, diet, or some other factor is

not known.

A common misconception is that

male and female birds are dif-

ferent in color. In fact, this is true

for only about half of all birds. It

is generally true of birds like

pheasants that nest in the open

and in species like cardinals

where the female alone incubates

the eggs. The male’s brilliant

color helps advertise his owner-

ship of a territory and attract a

mate. A great many tropical birds

and most birds that nest in col-

onies, like flamingos and _ ibis,

have both sexes colored the

same. What the advantages of

this may be are not entirely clear.

Certainly birds like the psittacines

and toucans that usually nest in

holes do not need protective

coloring on the nest, and birds

that nest in colonies are protected

by the large number of birds

present. But these are only partial

answers to a complex question.

What is the source of color in

birds? One visitor seriously asked

if the Zoo had painted the

lorikeets! Looking at the wonder-

ful colors and patterns, it is hard

to believe that color happens

naturally. Feather color comes

from several different pigments as

well as from the structure of the

feather itself.

White feathers are unpigmented,

but two groups of pigments are

responsible for many of the other

feather colors. Melanins give

black, brown, and dull yellow

colors, while carotenoids cause

most of the reds, oranges, and

yellows. Other colors are caused

not by pigments, but by the struc-

ture of the feather. Blues, most

greens and violets, and all the ir-

idescent colors are in this group.

Blues result from a cellular struc-

ture in the feather that breaks up

light so that only blue is reflected.

If these cells also contain red or

yellow pigment, the feathers will

be violet or green. A few birds

have a true green pigment; the

turaco is one such bird.

The striking iridescent colors of

hummingbirds, peacocks, and

even grackles are caused by

combinations of twisted, flat-

tened barbules in the feather

and an extremely complex

cellular structure. Different colors

are reflected as the light strikes

from different angles.

A mature feather is a finished

structure, but color changes may

take place as the result of exter-

nal factors. The cardinal starts the

fall with greyish tips on the

feathers. These wear away over

the winter, revealing his full crim-

son beauty by spring. House spar-

rows have a speckled neck band

in the fall, but the light tips of the

feathers wear off; by spring his

bib is solid black. Melanin seems

to result in a stronger structure

than unpigmented feathers; most

white birds have black wing tips,

since these feathers receive the

greatest stress.

Feathers may fade in sunlight or

be stained by iron in the water.

Sometimes the oil that the bird

applies in preening may affect the

color as it does the white tail

feathers of hornbills. If the bird’s

diet is deficient in some element,

the feathers appearing after the

next molt may lack color. This is

often a problem with captive

flamingos and other birds that

must have carotenoids to keep

them in full color. Foods rich in

carotene, which is related to

vitamin A, include crustaceans,

and algae.

Birds have excellent color vision,

and much of their communica-

tion and social life are governed

by the colors they display. Their

color is a source of pleasure for

zoogoers, but a vital element in

their survival. oO

by Sally Tongren

FONZ House Guide

21

n one sense, nearly all birds are

I birds of prey. Almost every

species occasionally captures

living prey. A robin catching a

worm is a predator, as is a

swallow chasing flies on the wing.

But when we think of birds of

prey, we think of falcons, hawks,

and eagles.

Falcons, hawks, and eagles all be-

long to an order of birds called

Falconiformes. Collectively, the

species in this order are known as

raptors.

There are a number of raptor

species at the National Zoo. They

may be large, like the imperial

eagle, which reaches a weight of

over six pounds and has seven-

foot wings, or small, like the

American kestrel that is not much

bigger than a robin.

Yet both of these species are su-

perb hunters. Both have the

hooked bills and sharp talons

characteristic of birds of prey.

Both have the keen eyes needed

to spot a rodent scurrying on the

ground. But there are differences

in hunting techniques between

the falcon and the eagle.

It will be three to four years before this

immature bald eagle will acquire its em-

blematic white head and yellow beak.

Two bald eagles have been born at the Zoo.

The imperial eagle soars for long

periods in search of prey. When it

sights suitable prey—a ground

squirrel, for example—the eagle

plummets to the ground. It grasps

the prey in its talons, which are so

long and sharp that they kill the

prey instantly.

The kestrel, by contrast, rarely

soars for long. Its sturdy wings

are designed for speed, not for

sustained soaring. Typically, it

watches for prey from a perch

like a telephone pole that pro-

vides it a good view. After spot-

ting its prey on the ground, the

kestrel can hover motionless in

the air—something a bird as large

as an eagle cannot do. Like the

eagle, the kestrel grasps prey with

its claws, but the sharp, short

claws are designed to hold prey

rather than kill it. The prey is

killed with a quick bite at the

back of the neck.

A few birds of prey live mostly on

carrion. Vultures and the crested

Caracara are such scavengers.

The secretary bird is another un-

usual raptor. Its name comes

from the long quills on its head,

which reminded naturalists of the

quill pens kept behind a_nine-

teenth century secretary’s ear.

Unlike other raptors, it does not

swoop down on the prey from the

air. It can fly, but seldom does.

Instead it strides through the Afri-

can grassland on long, slender

legs which are used to trample its

favorite prey, snakes. If a poison-

ous snake strikes back, the bird

will take the blow on its wing

feathers where it can do no harm.

Another order of birds contains

predators as highly evolved as the

raptors. These are the Strigi-

formes, or owls. Though owls are

apparently not closely related to

the raptors, they have evolved

many similar features. Like rap-

tors, owls have sharp talons and

hooked bills. But owls differ from

raptors since they are adapted for

night hunting, while raptors are

day hunters.

Owls have very large eyes, spe-

cially designed to make use of

very low light levels. Owls can see

well enough to find food at less

than one one-hundreth of the illu-

mination man would need. Of

course, even an owl cannot see

when there is no light at all. But

then the owl can rely on its un-

canny sense of hearing. In abso-

lute darkness, an owl can swoop

down on and capture a mouse,

guided only by the rustling

sounds the mouse makes moving

through leaf litter.

The )neeturnal mammals that

owls eat also have excellent

hearing. So owls have evolved the

Hooked bill and sharp alons enable

Africa’s secretary bird to trample and tear

apart its favorite prey — snakes. If a poiso-

nous snake strikes, the bird takes the blow

on its feathers where it can do no harm.

ability to fly almost noiselessly.

The flight feathers on the wings of

most birds are stiff quills. Owls

have downy fringes at their wing

edges that damper the sound of

beating wings.

Owls and raptors also eat their

23

prey differently. A raptor care-

fully plucks much of the feathers

or hair off a dead bird or mam-

mal before eating it. It will

usually then tear off pieces of

meat with its bill. Owls, on the

other hand, usually swallow their

prey whole, including bones,

feathers, and hair. Later, the owl

regurgitates a pellet of the indi-

gestible parts of the prey’s

carcass. By studing these pellets,

scientists know what owls eat.

Predatory birds have not gener-

ally been very popular with

humans. In the last century,

hunters gathered in the hundreds

to ambush vast flocks of migra-

tory hawks. Today hawks and

other predatory birds have legal

protection.

Even so, man still threatens the

survival of raptors and owls by

using pesticides, which accumu-

late in the tissues of predatory

birds, lowering fertility, and

causing thinning of eggshells.

Widespread habitat destruction

also threatens many such birds. O

by Austin Hughes

The snowy oil of the Arctic matches its

tundra-white environment. The “ermine

owl” has been known to fly as far south as

California and Texas.

24

The indoor flight room of the Zoo’s Bird House recreates a miniature tropical paradise where dozens of exotic birds live and breed as

they would in the wild.

ecently, most zoos have

Re aced their philosophies

about collecting and exhibiting

animals. In the past, excellence

was measured by how many

animals and species were exhib-

ited. Today, emphasis is on ex-

hibiting a diversified collec-

tion and particularly on propagat-

ing each species in captivity.

To do this, we must know a great

deal about the species’ natural

history. How does it live in the

wild? Does it live and breed in

large flocks, as does the fla-

mingo? What does it eat? Does

it have one mate—like most

species — or several, like the Zoo’s

great argus pheasant?

The more zoos know of the nat-

ural history of a species, the

better the chances of maintain-

ing and breeding them. For ex-

ample, while a few flamingos can

be kept in captivity for years, they

will never breed, because it takes

the interaction of a large group to

initiate breeding.

On the other hand, the mixing of

several individuals of a species,

such as the turacos, that estab-

lishes and maintains a large terri-

tory, can be fatal. The dominant

male will attempt to drive sub-

ordinates from his territory. If

they cannot escape, they will in-

25

Different birds require different exhibits.

As for the Zoo’s rufous hornbill, careful

attention is given to perch diameter, cage

size, floor surface, temperature, and light.

26

evitably die—the more aggressive

birds will either attack and kill or

prevent their feeding.

Just as important in selecting a

species for display is knowing the

successes and failures of other

zoos in meeting housing, dietary,

and health needs.

Space requirements for birds dif-

fer between species. The bird’s

size, its aggressiveness towards

Cagemates, and its breeding be-

havior must be considered. Gen-

erally, an exhibit should be large

enough to allow the birds to

move about freely and offer room

for escape from other birds and

from people. For birds that fly,

the ceiling should be high enough

to allow the bird to pass over a

keeper’s head.

“Critical distance” —the closest a

person can get to a bird without

the bird becoming alarmed—

must be considered for each

group. Birds at the Zoo are quite

accustomed to visitors and will

be calm if the visitors stay on

the walkways. If an untrained per-

son were to enter an exhibit, the

birds would probably become

alarmed. This could result in

serious, and even fatal, injury to

the birds.

In addition to the size of the ex-

hibit, zoos must consider the

floor surface, perches, and plants.

Each exhibit is a semi-natural

habitat, designed for a particular

bird or group of birds. Many dif-

ferent habitats, from arid desert

to humid, tropical forest, are re-

created in the Bird House.

A sandy soil, such as that found in

the elf owl exhibit, is necessary

for the growth of cactus and

other desert plants, but a rich top

soil is needed in the tropical room

for the tropical plants.

In many exhibits, such as the

cockatoos and hornbills, there are

no live plants, as these birds will

destroy them. In the wild, the

damage done is spread over a

large area and is not noticeable.

Compare the size of the perches

in the hornbill exhibit and those in

the toucan exhibits. Proper perch-

ing is a necessity, and a bird’s feet

should reach about two-thirds of

the way around a perch.

Temperature, humidity, and

amount of light are other ele-

ments considered under “hous-

ing.” Temperature and humidity

usually duplicate those found in

the species’ natural range. Tropi-

cal species cannot tolerate ex-

treme cold, just as Arctic species

cannot tolerate extreme heat. No

bird can cope with sudden, dras-

tic changes in temperature.

Why is humidity important to a

bird? Many tropical and sub-

tropical birds respond to high

humidity with increased breeding

activity. Their survival in the wild

depends upon it, as they must

produce young in the ‘rainy sea-

son” when there is enough food

available to rear the young! In

contrast, cold climate birds are

susceptible to airborne diseases

and fare poorly in humidity.

Changes in light can trigger the

development of certain glands.

The glands of many species be-

come active in response to an in-

crease in day length, while some

species also respond to a

decrease. Each indoor exhibit in

the Bird House has a separate

timer to control the light.

Within the 8,600-plus species of

birds found in the world, there

exists a great diversity in dietary

needs. Through evolution, special

feeding organs have evolved to

meet individual needs.

Birds of prey, such as eagles,

hawks, and owls, have a strong,

hooked beak for tearing their

food into small pieces.

Large parrots have beaks strong

enough to crack nuts, yet possess

a tongue that is supple enough to

extract the kernel. The flamingos,

which feed in the mud of shallow

waters, have curved bills lined

with hairlike bristles that filter out

small plants and animals.

Each bird at the Zoo is fed a diet

prepared just for that species.

Why do Zoo signs state, ‘Special

Diet - Do Not Feed’’? Because like

people, birds will fill up on junk

food and so spoil a diet.

Nutritional deficiencies often lead

to disease, such as those pro-

duced by viruses, bacteria, and

parasites. The keepers inspect

each bird daily to check for any

unusual behavior. Illness is often

indicated by a loss of appetite.

But prevention of disease through

good housing, nutrition, and sani-

tation is of prime concern to

zoos. Any new bird arriving at the

Zoo is quarantined for 30 days.

During this period, constant ex-

aminations are made to deter-

mine the bird’s health.

Once a species has been selected

for exhibit, and proper housing,

care, and nutrition have been

assured, how does the Zoo get the

birds? This is most often done

through communication between

zoos. Periodicals are circulated,

listing breeding successes, surplus

birds, and bird needs.

To supplement and improve this

procedure, the International Spe-

cies Inventory Systems has been

established to computerize _in-

ventories at one central location.

Net only is inventory data com-

puterized, but also the animal’s

health and ancestry records.

Once the needed species has

been located, there are local,

national, and international laws

to meet. Many permits and docu-

ments are needed to bring a bird

into the United States from a for-

eign country. Upon arrival, every

bird must spend 30 days at an

official U.S. Department of Agri-

culture quarantine center.

Even though the procedures to

acquire a bird are stringent, they

exist to insure the continued

survival of all wildlife! 0

by Charles Pickett

Curator of Birds

27

ot until the flightless dodo

was massacred by 17th Cen-

tury sailors for food did anyone

think about preserving birds. Even

since then, man has killed off the

passenger pigeon, Carolina

parakeet, and ivory-billed wood-

pecker. Other native American

species, such as the whooping

crane and California condor, are

on the verge of extinction!

Of course, birds have evolved

and have become extinct for mil-

lions of years because of changes

in climate and habitat. But only

recently has man become directly

involved.

Habitat destruction, pollution,

and indiscriminate use of pesti-

cides are just a few ways that

mankind has contributed to the

decline of wildlife.

If the world population reaches

seven billion by the year 2000, as

is expected, underdeveloped

countries will have to launch

new technologies and take land

now used by wildlife for the

survival of their people. Where

will the animals go when the grass

plains of Africa or the tropical

rain forests of Brazil are ploughed

for crops?

A winner in the battle against extinction,

the Hawaiian goose, or nene, was saved be-

cause a remaining few were captured,

bred in captivity, and returned to the wild.

By displaying fewer animals and

exhibiting them better, and by

breeding as many as possible, the

National Zoo is becoming a

modern-day Noah.

The swinhoe pheasant, which pro-

duces young regularly at the Zoo,

is now considered extinct in the

wild. This species formerly in-

habited the island of Taiwan.

The Hawaiian goose, or nene, is

the official bird of our fiftieth

state. Half the size of the com-

mon Canada goose, the nene

lives on dry, porous lava fields on

the island of Hawaii, and neigh-

boring Maui. It feeds on sparse

vegetation and gets water from

small, temporary rain pools. By

1949 a population that once num-

bered 25,000 had dropped t

fewer than 50! 7

Hunted until 1907 and then killed

off by introduced domestic ani-

mals, such as rats, dogs, and cats,

the nene population was further

reduced by habitat destruction un-

til only a few individuals re-

mained in the most inhospitable

parts of the islands.

In 1949 Mr. Charles W. Schwartz,

a wildlife biologist, suggested

captive rearing to save the nene.

The State of Hawaii established a

captive population that year, and

their efforts were joined in sub-

sequent years by many other in-

stitutions and individuals. The

breeding and the eventual release

programs were successful. Today,

over 1,500 birds have been re-

leased into the wild, and the

future of the nene looks brighter

than it has for over a century.

A nene breeding program began

at the National Zoo in 1963. Since

then over 50 young have been

produced and sent to other in-

stitutions to insure the continued

propagation and preservation of

this beautiful species.

The Zoo’s conservation efforts

are not limited to severely

threatened species. They apply to

all animals. What factors must be

considered to launch a_ bird

breeding program?

Information on breeding biology,

such as courtship, nest-building,

egg-laying, incubation, and

rearing of young, is crucial.

In many species, such as the

cranes, males and females look

alike. Many tests, such as blood

and fecal analysis, have been

developed to determine sex, but

most are not reliable.

Extreme accuracy is obtained at the

National Zoo by a simple surgical

technique called “laparoscopy.”

The laparoscope is a thin metal

The beginning of a bird is checked by a

keeper who candles an egg to examine the

developing embryo inside.

tube packed with glass for magni-

fication and designed so that a

light is projected through a tube.

By placing the tip of this instru-

ment under the skin, the veteri-

narian can actually see the sex or-

gans. Also, other organs, such as

liver and spleen, can be examined

for disease or malfunction.

29

Courtship behavior varies

between species. In the crowned

crane, both male and female bob

their heads up and down and

lightly dance around with out-

stretched wings, often leaving the

ground. Brilliantly colored areas

of plumage, exposed areas of

skin, and other physical adorn-

ments are used to attract a mate

in many species.

Nests range from cavities in the

ground to mammoth platform

nests built up by generations of

bald eagles. Quite often in cap-

tivity, the nest must actually be

constructed by man to encourage

the birds to breed.

The number of eggs produced by

a female in one nesting is usually

constant for each species.

Pigeons lay only one or two eggs,

while a quail produces up to 15.

Increased production is obtained

at the Zoo by removing the eggs

from some species for incubation

and hatching. The Indian sarus

crane normally produces two

eggs and, consequently, two

young per breeding season. By

pulling the first two clutches for

The egg, not the chicken, comes first in the Zoo’s incubation unit. Here, hundreds of rare

birds, from cranes to bald eagles, have begun life.

artificial incubation and leaving

the last clutch with the parents,

the Zoo produced six in 1977.

The Zoo’s bald eagles produced a

single chick in 1973 and have not

produced young since, even

though they have laid each year.

In 1977, the first clutch, which

consisted of two eggs, was

removed and. incubated §artifi-

cially. Then the female laid a

single egg, which she was allowed

to keep. After incubation had

been completed, both artificially

and naturally, it was found that

all three eggs were spoiled.

This year, the first two eggs will

again be artificially incubated.

One egg will be incubated at 100°

F. just prior to being dipped into

an antibiotic solution at 40° F.

The warm egg will draw the cool

antibiotic through the shell pores.

The second egg will be directly

injected with a different anti-

biotic. Hopefully the antibiotics

will destroy the organisms

causing decay, with the end result

a baby eagle! |

Research is also being conducted

on artificial insemination, which

has been used successfully in the

domestic poultry business for a

number of years. However, little

work has been done on artificial

insemination with exotic species,

but the Zoo has already produced

one young ocellated turkey

chick! It is conceivable that, in

the future, where a shortage of

males exists, semen collected

from one male can be used to

fertilize several females.

By emphasizing breeding, the

National Zoo is quickly becoming

a producer of wildlife. Eighty-five

percent of all the new birds in

1977 were hatched at the Zoo.

Hopefully, the current effort on

behalf of many individuals to

conserve all living things will in-

tensify and not die out. As John

Perry, former deputy director at

the National Zoo explained, “The

world is our zoo—a zoo that

must be well managed, its re-

sources carefully husbanded, for

these are the only resources it can

ever have. We have appointed

ourselves the keepers of this zoo,

but we cannot live outside its

gates. We are of it. Our lives are

inextricably intertwined with the

lives of all that live within. Their

fate will be ours.”

by Charles Pickett

Curator of Birds