We might also include in this category the snowy heron, the roseate spoonbill and other birds that have been slaughtered for their plumage. Although the economic value is here the direct motive for the slaughter, this value grows out of unusual (and beautiful) modification of the plumage.
The preceding paragraphs are necessarily sketchy, because the subject is too large to treat in detail and it is now desirable to gather up the threads.
Briefly, the general tendency of the North American fauna is toward mediocrity. Large species are giving way to small; bizarre species to commonplace. Marsh-loving and forest-loving animals disappear with the advance of civilization, and grass-loving species that are able to exist in fence rows and pastures survive. Animals that yield products of value vanish before the hand of man; likewise his enemies are destroyed unless protected by small size and great fecundity. Courage and the social instinct are at a discount and cunning and timidity at a premium.
Finally man is beginning (and only beginning) to shape the destiny of his God-given dominion "over the beasts of the field and the fowls of the air." To make this dominion an intelligent reality is the aim of present-day biological science.
