228 The Ruffed Grouse 



cidence reached in 1937 coincides with a minor decline in grouse 

 populations. How much significance this may have is conjectural. 

 Except for the records in New York and New England, the only 

 instance of Dispharynx in grouse is in a single bird recorded by 

 Fisher (1939) from Michigan. It was very heavilv infected. In do- 

 mestic fowl this parasite is known from many parts of the world. 



Ascaridia honasae (Wehr, 1940). This is an intestinal worm that 

 may be found almost anywhere in the alimentary tract, although 

 primarily in the small gut, and occasionally free in the body cavity. 

 Closely related species are parasites of the domestic duck and 

 chicken. 



The parasite is one of the largest infecting the grouse, varying 

 from about two to four inches in length; it is yellowish in color.^ 

 Ordinarily it does not affect the host seriously and no gross lesions 

 are produced in most of the cases. The life history probably parallels 

 that of a close relative in the chicken. Infection is acquired directly, 

 no intermediate host being necessary. Its primary effect is to deprive 

 the host of nutrients from the digested food in the intestine. 



Infections often are high, two hundred or more worms occasion- 

 ally being found in a single bird. Such numbers do not seem to 

 affect the grouse seriously although it has been observed that in 

 domestic chickens there may be a large enough number of worms 

 to prevent food from moving through the intestine. If this does occur 

 in grouse, it has not been obsei*ved and surely is rare. 



Allen and Gross (1926) found from one-quarter to one-third of 

 all birds they examined from various states to be affected with from 

 one to fifteen worms per bird. Clarke (1936) found this species to 

 be the commonest endoparasite of Ontario grouse, with incidence 

 ranging from zero to forty per cent in different areas and averaging 

 twenty-one per cent. Bough ton (1937) records an incidence of 

 thirty-seven per cent in five hundred and tl^irt^'-three Minnesota 

 grouse, with an average number of six worms per infected bird." 



Erickson (1944) found eleven of twenty-six birds from Minnesota 

 to contain this parasite. Fisher (1939) gives the rate of occurrence 

 in Michigan grouse as from twenty to thirty-seven per cent in differ- 

 ent years, with the number of worms averaging one to three. 



^ See Cram ( 1927) for complete description. 



" Boughton lii>ts the species as A. galli in the text although he gives it the name 

 A. Uneata in the first iiistence on puge 7 



