114 STATUS OF THE SPECIES 
Species which are the direct object of man’s unbridled greed, must 
succumb to an enemy before which neither swiftness of flight nor exces- 
sive wariness avail. Thus the Wild Pigeon and White Egrets, however 
well they were fitted to contend with nature, could not escape man. 
But when man enters the bird’s life only indirectly, altering its 
environment without actually killing the bird itself, the species in 
undiminished numbers is left to face the problem; and its ability to 
adjust itself to new conditions is now put to a vital and immediate test. 
The Pileated and Ivory-billed Woodpeckers have decreased with 
the forests; but the Crow and the Robin, both naturally forest-inhabit- 
ing species, have more than held their own. Both, in different ways, 
have adapted themselves to the new order of things; the Crow meets the 
distinctly hostile if not actively aggressive attitude of man by wariness 
and more than average intelligence; the Robin, through its fearless- 
ness, has won man’s friendship and protection. Near his dwellings its 
natural enemies have been reduced in number, and the normal food 
supply greatly augmented by fruits of various kinds, a more accessible 
supply of worms on close-cropped lawns, and various insects which 
also thrive on man’s bounty. 
The introduction into this country of the House or English Sparrow 
has, from a biological point of view, been an overwhelming success. 
Not only did the bird fill an unoccupied place in our cities, but when 
brought into competition with native species, its hardiness, general 
adaptability, pugnacity and continuous presence have all been in its 
favor. When the migratory Bluebirds or Purple Martins returned, they 
often found the Sparrows in possession of their nesting-boxes, and the 
decrease in the numbers of both these species is unquestionably to be 
attributed to their inability to compete with the Sparrow. 
In the changes wrought by man, directly or indirectly, we may 
find many similar illustrations of sudden alterations in the bird’s 
environment, and the manner in which they are met demonstrates what 
is meant by adaptability. In nature, equally great changes may occur, 
but they take place more slowly, and the adjustment between them and 
the bird, while not the less essential, is not so severe and sudden a tax 
on the bird’s resources. 
’ But aside from these external influences, which may remain un- 
changed and hence inactive for long periods of time, there are certain 
internal influences which are constantly potent. Chief among these is 
temperament as it is expressed in sociability or desire for solitude. It 
is obvious that only birds of social, or at least peaceable, disposition 
could live in such close juxtaposition as do colonial birds, like Gannets, 
Murres, Flamingoes, Cliff Swallows and many others, where nests or 
nesting birds almost touch one another. Such social species are usually 
represented by numerous individuals, while on the other hand the 
relative abundance of solitary ‘species is related to the extent of the 
area over which they claim guardianship while nesting, to the exclusion 
only of other birds of their own kind, Hence, Hawks and Owls, for 
