430 PARASITISM AND DISEASE L\ RUFFED GROUSE 



Blood Parasites 



The parasites that have been identified from the blood stream of New York grouse are of 

 only one type. Microfilaria. From Ontario, Clarke '■■ '• "' has reported two malaria-like para- 

 sites, Leucocytozoon and Haemoproteus and a spindle-shaped protozoon, Trypanosoma. The 

 last two have also been identified from grouse in Michigan. Leucocytozoon attacks young 

 grouse with serious consequences, according to reports. 



Microfilaria 



Distribution. These blood parasites have been found in grouse in Ontario and New York. 

 Since specific identification could not be made and no adults were found, it is impossible to 

 say whether the same worms exist in other birds. 



Description. Microfilaria are microscopic roundworms which occur in the blood. They are 

 presumably the immature stages of tissue dwelling roundworms. These forms have been found 

 in the blood smears of many birds, in which no adult filarial worms have been found. 



Life Cycle and Dissemination. The group of parasites to which the microfilaria belong de- 

 posit living embryos in the blood streams of their hosts. These are taken up 1)\ blood-suck- 

 ing insects when they feed and are transmitted to other hosts by their bites. 



Patkogenicity. So far as is known these parasites do not harm their hosts. 



Incidence and Importance. Microfilaria were not found in chicks and occurred in only 1.2 

 per cent of the adult. There is no reason to believe they are of any importance to grouse. 



External Parasites 



In the wild, the external parasites most consistently found on grouse are the ticks and louse 

 flies, although lice and mites are sometimes encountered. As has been noted in table 64, ticks 

 have been found on about 12 per cent of the birds during the summer months while louse flies 

 occur on from 2 to 7 per cent, depending on the age of the birds. It is only during the summer 

 months, when special collectors are in the field, that the freshly shot grouse are placed in wax 

 paper bags immediately on collection. The incidences given above are based on these summer 

 collections, although birds received throughout the year are examined for these parasites and 

 spring and fall occurrences have been recorded. 



Ticks ( Haemaphysalis chordeilis and H. le peris- paluslris) 



Distribution. As has been indicated at another point in this chapter, the majority of the 

 ticks identified from grouse during this Investigation, have been bird ticks (Haemaphysalis 

 chordeilis). Some rabbit ticks (II. le ports- palustrisj have been taken and probably some num- 

 bers of nymphal stages of ticks, which could not be identified to species, belong to the latter 

 group. The bird tick is also resident on other birds across the country, including chickens, 

 turkeys, spruce grouse and songbirds. Il has been implicated in the transmission of tularemia 

 among sage hens. The rabbit tick is found on cottontails, varying hares and jackrabbits as 

 well as on a number of other species of mammals and birds throughout most of North 

 .America. Ticks were found on grouse in all three regions in New York but they were more 

 abundant in the Adirondacks than in other parts of the State. 



Description. The licks found on grouse manifest different si/cs and shapes depending on 

 their age and state of engorgement. As they suck blood from their hosts they increase in size, 

 the largest being about % of an inch long and roughly spherical or ovoid. The females are 



