Preview Guide for Encyclopedia Article




Yüklə 24.91 Kb.
tarix29.04.2016
ölçüsü24.91 Kb.

TM2 Name ________________________________________


Read the statements about waterfowl before reading the article. Check in either the “agree” or “disagree” column. Skim the article to locate the correct information. Highlight the parts of the statements that are not true.

Preview Guide for Encyclopedia Article

Waterfowl

Statement

Agree

Disagree

  1. Geese preen their feathers because they want to look good.


  2. Some waterfowl migrate up to 6,000 miles one way.

  3. Waterfowl migrate by following paths called “flypaths”.

  4. A baby duck, goose, or swan thinks that any object near them when hatching is its parent. This is called "bird adoption”.

  5. Geese fly in a “Y” formation which makes flying easier for the whole flock.

Waterfowl


There is not another group of birds that is as

well known as the family Anatidae--the

waterfowl. No matter where you live, it is

likely there are waterfowl--ducks, geese, or

swans--nearby.
There are 148 species in the Anatidae family

with 57 species living in North America. All

of these waterfowl share certain physical

features. They all have short legs with

webbed feet that help them swim and dive.

The majority of them have flattened bills with

specialized edges that are used for picking up

food from the water and straining it.


All waterfowl, or "wildfowl" as they are

called in European countries, have outer

feathers that are very oily. The oil is

produced by a preen gland located just over

the tail. The oil is worked into the feathers by

the bill in an act called preening. If you

watch a duck, goose, or swan at rest, you will

see that the bird seems to "bite" the top of the

tail then comb its feathers with its bill. It is

actually waterproofing its feathers with the

oil.

Beneath the outer feathers is a lining of down



(small fluffy feathers) plus a layer of fat,

which provide insulation. Because the oiled

outer feathers do not allow water to pass

through, the inner lining of down rarely gets

wet. That is why waterfowl are able to swim

and still remain warm and dry during the

winter, while we humans stand shivering on

the shoreline!


Nearly all the waterfowl are strong fliers.

They may fly thousands of miles during the

spring and fall migration seasons. You have

probably seen migrating geese flying

overhead in a V-formation, or wild ducks

making rest stops in city and country ponds.

In some cases, especially in the Southern

Hemisphere, some types of waterfowl do not

migrate and spend their entire lives in the

same area.


Individual species that travel south in the fall,

and back north each spring, will fly as far as

9,600 kilometers (6,000 miles) one way. The

blue-winged teal, a small duck, makes this

long trip from its nesting grounds in the far

north to its wintering place in the Southern

Hemisphere.
Waterfowl often travel well-defined flight

paths. In North America there are four such

wide paths known as "flyways." They are

called the Atlantic, Mississippi, Central, and

Pacific flyways. These flyways were

determined by biologists who studied banded

waterfowl.
Another interesting feature common to

waterfowl is their habit of imprinting. This

means that a baby duck, goose, or swan will

identify anything near it after hatching--from

a chicken to a human being--as its parent.

Experiments have shown that any large,

moving object, even a balloon or a puppet,

will be treated as a parent by a downy

youngster. It is difficult to return orphaned

birds to the wild once they are imprinted by

anything other than their natural pare

Geese

Fourteen varieties of geese can be found

throughout the world. Nearly all of them live

in the Northern Hemisphere and make long

migrations in the winter, though they do not

fly as far as most ducks.


In body size, geese are generally larger than

ducks and smaller than swans. The weight of

adult birds ranges from 1 to 9 kilograms

(about 2 to 20 pounds). Unlike ducks, it is

not easy to distinguish the male (called the

gander) from the female (properly called the

goose). Both birds have identical coloring.
Geese are highly gregarious, which means

they like to be in the company of their own

kind. On the wintering grounds massive

flocks of 20,000 or more birds are sometimes

seen.
Mating Habits. Males and females mate for

life, although if one dies, the other will often

find another mate. The youngsters, called

goslings, stay with their parents throughout

their first year of life. Most geese do not mate

until they are three years old.


Male geese establish the nesting territory and

defend it from intruders and predators. The

nests are built of grasses, twigs, and reeds.

They are often located along the shoreline, in

grasses or reeds, or atop muskrat houses.

The nest is lined with down from the female's

breast. Four to seven eggs are in the usual

clutch, and they hatch in three to four weeks.

Unlike the male duck, the gander stays with

the female and helps protect and raise the

offspring. After hatching it takes from 40 to

85 days for the young to begin flying.

Migration. Canada geese and various other

species fly in a V-formation, or wedge. The

wedge has a leader, and each successive

goose flies slightly to the left or right of the

leader to form the V. The movement of air

by the wings of each bird makes the task of

flying a bit easier for the bird in back of it.

Obviously, the leader has to do the most

work. On long flights several leaders will take

turns at the job.


Eating Habits. Like most waterfowl, geese

eat many types of vegetation. Their bills are

also equipped for clipping grasses and leaves.

They frequently stop in cornfields to pick up

leftover grain. They sometimes cause

problems on golf courses where they pluck

the green grass, roots and all.
Types of Geese. The Canada goose is North

America's best-known species of goose.

Throughout the continent there are eleven

subtypes of Canada geese that look very

much alike but differ in size. The smallest,

called the cackling goose, weighs from 1 to 2

kilograms (about 2 to 4 pounds). The largest,

the giant Canada goose, can grow to 7

kilograms (almost 16 pounds) or more.
Geese vary greatly in colors. Canada geese

and brants, small marine geese, are

sometimes referred to as "black geese"

because of their many black feathers. "Gray

geese," such as the white-fronted goose and

the rare emperor goose, have feathers that

range from gray to white.
The beautiful snow goose and the small

Ross's goose are pure white. Often these

geese will not have pure colors until their

second or third years of life because it takes a

long time for the adult plumage to develop.

The blue goose is a color phase of the snow

goose. The tiny Ross's goose also has the

distinction of being the world's smallest

goose--a mere 1.3 kilograms (less than 3

pounds).
Goose Hunting. Geese, like ducks, are

heavily hunted in the United States and

Canada. Economically they are very

important to people in places such as the

Chesapeake Bay region in Maryland,

Delaware, and Virginia where millions of

dollars are spent by visitors who come to see

and hunt them.
Goose down, which is collected from dead

birds, is also important for insulation in winter

clothes. However, synthetic products have

made expensive down clothing and sleeping

bags less popular.
Most of the world's geese are present in high

numbers, assuring their survival. Only the

Hawaiian goose, or "nene," is endangered.

This species almost became extinct in the

1950's. Only through human concern for

them have their numbers increased since that



time.


Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur ©azrefs.org 2016
rəhbərliyinə müraciət

    Ana səhifə