54 



corn billbugs, corn-leaf beetles, cucumber beetles, ticks, horse- 

 flies and mosquitoes. Nine species are known to feed on 

 mosquito larvae, and doubtless others do so. 



Egrets and herons eat many crawfish. Crawfish destroy 

 young fish; they also burrow into dykes, and thus become at 

 times a serious menace to the levees of the lower Mississippi. 

 In recent years, since the great destruction of egrets in the 

 southern States, immense damage to crops by crawfish has been 

 reported from Alabama and Mississippi, where over a wide 

 stretch of country " estimated at not less than 100 square miles, 

 they have prevented to a very considerable extent the successful 

 production of cotton and corn." l Can this be a mere coincidence? 



The National Association of Audubon Societies made an 

 examination of the stomach contents of young herons and 

 egrets. The results, tabulated below, prove these birds to be 

 destroyers not only of crawfish but also of insect pests. 



Food of Young Herons. 



[Based on the examination by O. E. Baynard, Orange Lake, Florida, of 50 meals of each of the 



following species.] 



Young herons have a very accommodating and hospitable 

 habit of presenting their food to visitors by regurgitation after 

 they have eaten it, and adult birds when suddenly frigntened 

 or disturbed often drop food from their bills. It is easy, there- 

 fore, to make a rather comprehensive survey of their food in 

 the heronry without actually killing the birds. In 1915 fisher- 

 men on the Massachusetts coast complained that black-crowned 

 night herons, which had increased under protection for several 

 years, were catching so many eels that they were endangering 



1 Fisher, A. K.: Crawfish as Crop Destroyers, Yearbook, United States Department of 

 Agriculture, 1911, p. 322. 

 * Frogs. 



