THE LAND ETHIC 
no land ethic yet, but we have at least drawn nearer the 
point of admitting that birds should continue as a matter of 
biotic right, regardless of the presence or absence of eco- 
nomic advantage to us. 
 
A parallel situation exists in respect of predatory mam- 
mals, raptorial birds, and fish-eating birds. Time was when 
biologists somewhat overworked the evidence that these 
creatures preserve the health of game by killing weaklings, 
or that they control rodents for the farmer, or that they prey 
only on 'worthless' species. Here again, the evidence had to 
be economic in order to be valid. It is only in recent years 
that we hear the more honest argument that predators are 
members of the community, and that no special interest has 
the right to exterminate them for the sake of a benefit, real 
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