PARASITES OF WILD GROUSE 433 



external parasites. Related flies (Lynchia hirsutaj and ( Lynchia fusca) have been shown to be 

 vectors of malaria-like diseases of CaUfornia valley quail^-"". Another form, Pseudolynchia 

 canariensis, serves as the intermediate host of a related blood parasite of pigeons^'. Al- 

 though Clarke' has reported a Haemoproleus infection in grouse and suggested the louse fly 

 as the possible vector, no conclusive evidence exists to confirm this view. 



Incidence and Importance. The low incidence of this parasite and the little trouble which 

 it apparently causes, seem to indicate that this organism is of no great importance in limit- 

 ing grouse abundance. 



Parasites Not Encountered During the Investigation 



During the course of investigations on grouse carried on in other parts of the country, a 

 number of parasites have been recorded which have not been encountered in Aew York or 

 which appeared so infrequently as to make evaluation of their role impossible. 



Important among these is a parasite of the red-blood cells of grouse, (Leucocytozoon bon- 

 asae), first noted in Ontario and since found in Michigan and Maine. It is presumably trans- 

 mitted by the bite of the black-fly (Simulium venustum). Clarke' in studying Canadian grouse, 

 considered it "significantly associated with the cyclic diminution" in numbers. O'Roke, who 

 has made a study of the malaria-like disease of ducks^ caused by Leucocytozoon anatis, also 

 regarded this grouse parasite to be pathogenic in young birds^"', though he did not study it 

 during a period when die-off was apparent. 



During the Investigation, blood smears from 781 grouse were examined for the presence of 

 this parasite. Of these, 214 were not taken during the summer months and therefore might 

 not be expected to show the parasite. Of the smears taken during the summer, 106 were from 

 adult birds and 461 were from chicks. None of the smears examined revealed the presence of 

 the parasite. 



In addition to the blood smears, livers, in which certain stages of Leucocytozoon are found, 

 were saved for miscroscopic study. Of the 195 livers examined, 117 were from chicks and 78 

 were from birds over three months old collected in October and November. These likewise 

 were negative. The blood smears and livers from birds taken in many parts of the State, 

 though the majority of the specimens came from Essex and Lewis Counties in the Adiron- 

 dacks, Tompkins County in the Southern Tier and from southern Albany County at the 

 northern edge of the Catskills. 



A related one-celled animal (Haemoproleus sp.) which inhabits the red blood cells of ruffed 

 grouse was found in Ontario by Clarke" in the summer of 1935. Nothing is known of its 

 effect on grouse. A parasite of the same genus is transmitted to California valley quail by 

 louse flies^ and it has been suggested that the same process may occur in ruffed grouse. Still 

 another protozoan (Trypanosoma) which lives in the fluid portion of the blood but not in the 

 blood cells, has been reported from ruffed grouse in Michigan'^' and Ontario'' but no disease 

 condition is attributed to its presence. 



Certain one-celled intestinal parasites have been described from New England grouse, though 

 they apparently are associated with no conditions harmful to the bird. These organisms move 

 by means of whip-like structures and are commonly known as flagellate* (Trichomonas 

 bonasae)^'", (Cyathosoma striatum), ( Ptychostoma bonasae )''' . Shillinger and Morley''' have 

 reported that similar organisms, resembling Trichomonas gallinarum, have been observed to 

 cause a highly fatal disease of young quail and grouse. 



