57 



eminent. The people of the State of New Jersey for years and 

 years industriously killed off wild-fowl and shore birds for the 

 market. Now they are on record as spending $3,500,000 a year 

 in fighting mosquitoes. 1 But New Jersey is not alone, either in 

 such killing or in such subsequent expenditure. 



Probably most surface-feeding ducks that get a large part of 

 their summer food about the margins of ponds and pools de- 

 stroy incalculable numbers of mosquitoes by eating the larvae 

 which abound in such places. Dr. Samuel G. Dixon, commis- 



THE MALLARD. 



A destroyer of disease-distributing mosquitoes. (From Game Birds, Wild Fowl and 



Shore Birds.) 



sioner of public health in Pennsylvania, writes that for some 

 years he has used ducks to keep down mosquitoes in swamps 

 that were difficult to drain, but that he never fully appreciated 

 the high efficiency of the duck as a destroyer of mosquito life 

 until he made the following test in a swamp after several un- 

 successful attempts to destroy the mosquito larvae by intro- 

 ducing fishes. He divided the swampy area into two equal 

 parts, each about 1,400 square feet in extent. One pond was 



1 Washburn, F. L.: Fins, Feathers and Fur, June, 1915, p. 7. 



