The Diseases and Parasites of Wild Ruffed Grouse 247 



ing an increase in the rate of infestation and in the degree of infesta- 

 tion as the birds become more numerous. The correlation is also 

 connected with the abundance of other tick host animals, notably 

 hares and rabbits. 



Clarke ( 1936 ) said that "Ticks were found on most of the speci- 

 mens collected ..." in Ontario. Allen and Gross (1926) recorded 

 heavy infestations on eight of fifteen birds taken in northern Maine, 

 and stated that ticks ". . . were likewise reported on birds in Al- 

 berta, Canada." 



Ticks have been found more commonly on the chicks than on the 

 adults in the New York study {N. Y. S. Cons. Dept. Ann. Reps., 1932- 

 42). With both age-classes tick occurrence has varied greatly in 

 different years, and is low judging by Midwest standards. The first 

 instance was that of a single adult bird in 1933. No further cases of 

 ticks infesting adults were noted until 1939. Sixteen instances in the 

 three years, 1939-41, a negligibly low incidence, were all. None was 

 found in 1942. The first ticks on grouse chicks were twenty-five cases 

 in 1934, representing an incidence of fifteen per cent. They were 

 identified as H. leporis-palustris. Next year the incidence dropped 

 to six per cent (seven cases); then for two years the record was 

 incomplete, although there were numerous cases of tick infestation 

 in 1937. No chicks were found infested in 1938, but for the next 

 three years the incidence increased yearly. From a six per cent (ten 

 cases ) rate of infestation in 1939, it rose to twenty per cent in 1940 

 (twenty-eight cases) and twenty-one per cent in 1941 (twenty-four 

 cases). The next year none was reported. From 1935 to 1940 the 

 species was called H. cinnaharina; in 1941 it was determined as 

 H. chordeilis. 



In addition to the possibility of transmitting tularemia to grouse, 

 ticks may cause the birds considerable discomfort, and occasionally 

 ill health. The ticks tend to congregate about the head and neck and 

 may cause this area to be almost completely denuded of feathers. 

 With the young birds especially, the drain of blood as the ticks 

 engorge themselves may reduce the bird's vitality, and sometimes 

 result in death. 



Louse Flies. A single species of the true flies (Diptera) is of 

 fairly common occurrence on grouse, both young and adult. It is a 

 hippoboscid, Lynchia americana ( Leach ) . Allen and Gross ( 1926 ) 



