248 



BOARD OF AGRICULTURE. 



[P. D. 4. 



Touissant of Rio, St. Lucie County, Florida, says that a black 

 snake (probably of this or the following species) actually 

 crawled up the weather boards of a house to a window where a 

 canary was swinging in a cage, and swallowed the bird, which 

 so increased its size that it could not get out of the cage.^ 



Professor H. A. Surface, who has made the most complete 

 study of the food of the serpents of Pennsylvania yet under- 

 taken, finds that during the late spring and early summer the 

 eggs and young of birds form the predominating food of the 

 pilot snake; later it feeds more on mice, insects, etc. The dia- 

 grams show this plainly. 



Z 



Cttlieronio 



FIE.LD 

 MICE. 



^^ 5hAKE5 



Diagram showing the percentages of food items of black snake {Bascanion constrictor) for the 

 year: 25 per cent insects; 15 per cent snakes; 22 per cent field mice; 8 per cent birds' eggs; 

 4 per cent rabbits; 4per cent voles; 73/^ percent frogs; 4per cent birds; 7 per cent mammals 

 (unidentified); 3H per cent larva of royal moth (Citfteroma reffoZts). (After Surface.) The 

 percentage of birds for June and July, when the young are in the nests, would be very much 

 larger; but the insects, mice and snakes eaten go far to balance the destruction of birds. 



The black snake or blue racer (Bascanion constrictor) differs 

 from the pilot snake in having no white except upon the chin 

 and throat and in having all the scales smooth instead of 

 keeled. The ventral plates are about 185 in number. The 

 snake is lustrous black in color, bluish or greenish below and in 

 length usually 5 feet or less, although larger specimens have 

 been taken. 



» The Bluebird, Junior Audubon Monthly, Vol. VII., No. 8, May, 1916, p. 222. 



