There are three kinds of extermination: 

The practical extermination of a species means the destruction of its members to an extent so thorough and widespread that the species disappears from view, and living specimens of it can not be found by seeking for them.  In North America this is to-day the status of the whooping crane, upland plover, and several other species.  If any individuals are living, they will be met with only by accident.

The absolute extermination of a species means that not one individual of it remains alive.  Judgment to this effect is based upon the lapse of time since the last living specimen was observed or killed.  When five years have passed without a living “record” of a wild specimen, it is time to place a species in the class of the totally extinct.

Extermination in a wild state means that the only living representatives are in captivity or otherwise under protection.  This is the case of the heath hen and David’s deer, of China.  The American bison is saved from being wholly extinct as a wild animal by the remnant of about 300 head in northern Athabasca, and 49 head in the Yellow-stone Park.

It is a serious thing to exterminate a species of any of the vertebrate animals.  There are probably millions of people who do not realize that civilized (!) man is the most persistently and wickedly wasteful of all the predatory animals.  The lions, the tigers, the bears, the eagles and hawks, serpents, and the fish-eating fishes, all live by destroying life; but they kill only what they think they can consume.  If something is by chance left over, it goes to satisfy the hunger of the humbler creatures of prey. In a state of nature, where wild creatures prey upon wild creatures, such a thing as wanton, wholesale and utterly wasteful slaughter is almost unknown!

When the wild mink, weasel and skunk suddenly finds himself in the midst of scores of man’s confined and helpless domestic fowls, or his caged gulls in a zoological park, an unusual criminal passion to murder for the joy of killing sometimes seizes the wild animal, and great slaughter is the result.

From the earliest historic times, it has been the way of savage man, red, black, brown and yellow, to kill as the wild animals do,—­only what he can use, or thinks he can use.  The Cree Indian impounded small herds of bison, and sometimes killed from 100 to 200 at one time; but it was to make sure of having enough meat and hides, and because he expected to use the product.  I think that even the worst enemies of the plains Indians hardly will accuse them of killing large numbers of bison, elk or deer merely for the pleasure of seeing them fall, or taking only their teeth.

[Illustration:  SIX RECENTLY EXTERMINATED NORTH AMERICAN BIRDS
Great Auk Labrador Duck
Eskimo Curlew Pallas Cormorant
Passenger Pigeon Carolina Parrakeet]