NORTHERN AND MARYLAND YELLOWTHROATS 553 



insects as leafhoppers and leaf rollers which are abundant among 

 the grass and low-growing herbage that it frequents. 



E. H. Forbush (1907) writes: "I watched a Maryland yellowthroat 

 on the low willow sprouts, and saw him pick off fifty-two gipsy moth 

 larvae before flying away." Mr. Forbush concluded in his study of 

 the gipsy moth infestation in Massachusetts that the yellowthroat 

 ranked among the efficient enemies of this pest. At another time 

 Mr. Forbush saw one eat 89 aphids during the course of one minute. 



S. A. Forbes (1883), in the examination of three stomachs of the 

 yellowthroat, found four-fifths of the food consisted of canker worms 

 and other undetermined caterpillars, 8 percent consisted of Coleop- 

 tera (beetles), gnats amounted to 4 percent, and a small hemipteran 

 {Piesma cinerea) was found. Others have reported yellowthroats 

 in orchards where their chief food seemed to be cankerworms. A. W. 

 Butler (1898) gives the summary of food eaten by 11 specimens of 

 the yellowthroat examined by Prof. F. H. King as follows : 22 case- 

 bearing caterpillars, 5 other larvae, 6 small dragonflies, 3 moths, 3 

 dipterous insects, 3 small hymenopterous insects, 3 beetles, 3 spiders, 

 2 small grasshoppers, 1 leafhopper, 2 hemipterous insects, and 2 

 insect eggs. J. Henderson (1934) quotes Aughey as having reported 

 8 locusts in the stomach of a single Maryland yellowthroat. C. W. 

 Townsend ( 1905 ) found beetles, flies, and small seeds in the stomach 

 of a Maryland yellowthroat he collected at Ipswich, Mass., on De- 

 cember 6, 1903. 



Under ordinary conditions the yellowthroat secures its food in an 

 environment remote from agricultural areas, orchards, and gardens ; 

 thus it may be thought to be of little economic importance. How- 

 ever, since many destructive insects breed in areas inhabited by these 

 birds, and from there spread to cultivated areas, the yellowthroat can 

 be considered a useful insectivorous bird in its food-eating habits. 



Nelle E. Shaver (1918) who made a nest study of the Maryland 

 yellowthroat at the Iowa Lakeside Laboratory on Lake Okoboji has 

 presented detailed and painstaking observations on the food delivered 

 to the young by the adult birds. Miss Shaver summarized the re- 

 sults of 1,694 observations made over the entire nesting period from 

 the time the young hatched until they left the nest. The food de- 

 livered was as follows: Unidentified insects 376, moths 347, various 

 larvae 290, spiders 280, mayfles 116, flies 61, unrecognized material 

 92, caterpillars 20, damselflies 54, beetles 13, chrysalids 13, butterflies 

 11, seeds 10, caddisflies 3, grasshoppers 6. Miss Shaver states further : 



The birds gleaned their food from the ground and the shrubbery close to the 

 ground. The greater amount of the food for the young was such as must have 

 been picked from low bushes around the nest. The small moths which were 

 so numerous in the grass, seemed to afford an unfailing source of supply. * * * 



