432 PARASITISM AND DISEASE IN RVFFED GROUSE 



In only one case, however, was the death of a l)ii(J attiil)uled to these parasites. On June 

 6, 1940, an adult female grouse, somewhat emaciated, was found near Glens Falls in a dying 

 condition. It was sent to the Research Center and died enroute. Aine adult bird ticks, all 

 fully engorged, were found attached about the neck close to the head. It was apparent that 

 their presence had caused much irritation. In fact, many feathers had heen lost from the 

 region. Complete examination of the bird revealed conditions indicative of starvation. No 

 food or grit had been taken in some time, the gizzard was flabby and death was attributed 

 to malnutrition developed as a result of this external parasitism. 



The relation of ticks to tularemia in birds and mammals has been considered elsewhere*. 



Incidence and hnpurtance. Only during the summer has accurate data been obtained to 

 indicate the incidence of infestation and the number of ticks per bird. Grouse in the Adiron- 

 dacks were more frequently infested tlian those in the other regions of the State and each in- 

 fested bird in that region harbored more ticks than were observed on individual hosts in other 

 regions. The heaviest infestations were observed and the greatest numbers of grouse were 

 found to have ticks during July. These parasites were found in about the same degree each 

 year. Xo cases were observed in which the number of ticks exceeded 300, though much hea- 

 vier infestations have been reported in the mid-west. 



The first record of ticks obtained by the Investigation was that of two from a captured 

 chick, 12-14 days old, during the summer of 1930 and were identified as //. chordeilis. The 

 earliest date on which ticks were found on adult grouse during the Investigation was May 4th. 

 Though no accurate count after the end of August is available, field observations seem to 

 indicate that these parasites are rarely found on grouse as late as the hunting season in Octo- 

 ber. Adult ticks are readily observed on account of their size. Many amateur observers have 

 therefore considered them to be important causes of grouse decimation. Yet, evidence of ex- 

 tensive damage has not appeared during the course of the Investigation. This is another case 

 in which the obvious parasites prove to be less important than the inconspicuous ones. 



Louse Fly (Lynrhia americana) 



Dislribution. This parasite commonly found on grouse during the warmer months, is 

 also frequently encountered in New York on great horned owls and on marsh, red-tailed, and 

 broad-winged hawks. In other localities in North America, a number of other hawks and owls 

 have also been reported as hosts of this fly. 



Description. Though these insects have been called "flying ticks" the\ are in reality, flies 

 which are adapted to an ectoparasitic existence. They have flattened brownish bodies and 

 long wings which bring their t(jtal length to almost ^^ i'K'h. Since they quickly lea\e the body 

 of a dying bird, they are seldom observed uidess the freshly shot gnmse is immediately 

 located and retrieved, lender these conditions, they may be noticed h\ the sportsman during 

 the hunting season. 



Lije Cycle and Dissemination. Little is known of the life cycle of tliesc insects. In flies of 

 this group (Pupii)ara) the eggs are not laid by the female but are retained within her body 

 where they hatch and develop to the state of pupation before they are deposited. It has been 

 suggested that the adults do not survive the winter in temperate regions. If this is the case, 

 reinfestation of non-migratory birds must take place each spring when the migratory hosts 

 return. Certain is it that they have not been encountered in the spring earlier than March 26. 



Pathogenicity. No deleterious effects have been observed as a result of iMfcstatiim with these 



* See dilcusBtun of Relation of DiscaBCB uf Wild Mammal* lu Grouie, p. 416, 



