230 The Ruffed Grouse 



five hundred and thirty-three birds (one to tliree worms each); he 

 identified the species as H. gallinae. 



In the adult birds examined during the New York study, six hun- 

 dred and thirty-two or thirty-one per cent had this parasite present. 

 The incidence varied from zero to seventy-three per cent in different 

 years, with 1935 to 1937 being the high period. This worm was 

 found in only four of nine hundred and thirty-two chicks examined 

 over a nine-year period. 



There is no indication that this parasite is of serious consequence 

 to the ruffed grouse. 



Cheilospirura spinosa (Cram, 1927'). This is a slender, whitish 

 worm that inhabits the gizzard between the muscular walls and 

 chitinous lining. Its length varies from about three-quarters to one 

 and one-half inches, and the body usually assumes a twisted shape. 

 Its life history involves an intennediate stage in a grasshopper 

 (Cram, 1931). 



Its distribution appears to be quite general in the range of the 

 ruffed grouse. First discovered in 1925 by Stafseth and Kotlan in 

 Michigan specimens, it was found commonly in the birds examined 

 by Allen and Gross ( 1926) except in those from New England. They 

 reported the highest incidence of infection from Michigan birds 

 ( forty-two per cent ) and twenty-one per cent of those from Minne- 

 sota, twenty-two per cent of Pennsylvania grouse, nineteen per cent 

 of Wisconsin specimens, fourteen per cent of those from New York, 

 and three out of eight birds examined from New Jersey, revealed 

 them. The average number of worms was about twelve to sixteen 

 but in some cases varied up to forty. Only in the most severe in- 

 fections was any damage apparent— an abnormal thickening of the 

 muscular wall, and even this seemed to cause little damage. 



Gross ( 1930 ) reported that "This parasite was found to be com- 

 mon, particularly in specimens received from New England." 

 Mueller ( 1941 ) again recorded its occurrence in New Hampshire. 

 Clarke's ( 1936 ) records from Ontario showed an average infection 

 of Cheilospirura of nine and two-tenths per cent, with variations at 

 different locations of from none to fourteen and eight-tenths per 

 cent. He found a few cases severe enough to cause serious lesions 

 but noted that in these instances the bird's vitality must have been 



^ See Cram, 1927, for complete description. 



