54 THE IMPORTANCE OF BIED LIFE 



In a vague way we realize that they are seeking 

 insects, but our imagination ceases to work fur- 

 ther; the actions of such birds are too common- 

 place to be worth a second thought. And yet at 

 that moment those very birds may be con- 

 suming mosquitos at the rate of several a minute 

 or snapping up itinerant house-flies which later 

 would have made our kitchens their home. Five 

 hundred mosquitos have been taken from the 

 stomach of a nighthawk merely the remnants of 

 one meal. Barn swallows are inordinately fond 

 of house-flies, and, together with the swifts, they 

 destroy thousands of winged ants. 



One of the most important economic functions 

 of wood-ducks, mallards, and others is their habit 

 of destroying enormous numbers of mosquito 

 larvae which infest the pools where they feed. 

 This fact was learned some years ago and brought 

 into public prominence by Dr. Samuel G. Dixon, 

 commissioner of public health in Pennsylvania. 

 He estimated that if the birds were present in 

 their numbers of a hundred years ago, they would 

 prove of vital importance in checking the spread 

 of malaria. Market gunners, however, and the 

 general indifference of the public to a promiscuous 

 slaughter of our game-birds have made this for- 

 ever impossible. Wood-ducks at present are not 

 far from extinction, and mallards and green- 

 winged teal are in a fair way toward suffering the 

 same fate. 



