VALUE OF BIRDS TO MAN. 81 
Navigators approaching their home port during seasons 
of bird migration welcome the appearance of familiar land 
birds which are seen while land is still far out of sight. Mr. 
Frank M. Chapman has shown, in an interesting paper on 
the ornithology of the first voyage of Columbus, that we 
possibly owe the discovery of America by Columbus to the 
fact that he happened to approach the land at the right time 
and place to cross the line of the fall flight of land birds that 
were going from the Bermudas to the Bahamas and Antilles. 
The discouraged seamen were on the verge of mutiny, and 
might have compelled Columbus to return to Spain, had not 
small land birds come aboard unwearied and singing. The 
course of the vessel was changed to correspond with the 
direction of their flight, and the voyage was thus shortened 
two hundred miles and pursued to its end.1 
The well-known services of Vultures, which destroy gar- 
bage and carrion in the tropics, have no real counterpart in 
the north. Crows are of some use, but Gulls and other 
water-birds are most valuable to man in this respect, in that 
they devour the garbage and refuse that are cast into harbors 
and arms of the sea, thus undoubtedly preventing the pollu- 
tion of many bays and beaches by floating filth and refuse 
from great cities. 
Sea birds must be reckoned among the chief agencies which 
have rendered many rocky or sandy islands fit for human 
habitation. The service performed by birds in fertilizing, 
soil-building, and seed-sowing on many barren islands has 
entitled our feathered friends to the gratitude of many a 
shipwrecked sailor, who must else have perished miserably 
on barren, storm-beaten shores. 
THE COMMERCIAL VALUE OF BIRDS. 
In all the foregoing we have considered mainly “the good 
offices that birds voluntarily take upon themselves in our 
service.” We have yet to take into account the tax which 
we impose upon them for our own revenue of profit or 
pleasure, —a tax which we collect unsparingly, and with the 
strong hand of force. 
+ Papers presented at the World's Congress on Ornithology, 1896, pp. 181-185. 
