PARASITES OF WILD GROUSE 427 



asites on growing chickens, no similar evidence could be adduced from observations on tape- 

 worms in young grouse. In a few cases, excessive mucus production by the intestinal cells was 

 attributed to the presence of the parasites but no more serious changes were observed even in 

 heavy infections. The weights of parasitized birds compared favorably with those not infected 

 but of the same age. 



Incidence and Importance. Though the incidence in chicks less than two months old is rela- 

 tively high, being 16.6 per cent during the first month and .32.2 per cent in the second, the 

 lack of lesions and the good physical condition of the infected birds seems to indicate that 

 little harm is caused by the presence of this parasite under natural wild conditions. As the 

 summer progresses the number of chicks infected drops off to 2 per cent in August and there- 

 after it is very seldom found. 



Small Tapeworm ( Hymenolepis microps) 



Distribution. This parasite is found in the ruffed grouse in iNew York and Ontario, in the 

 ptarmigan, and in the red grouse, the black grouse and in the capercailzie in Europe. It 

 occurs in all three regions of New York. 



Description. The tapeworms of this species are found attached by their head end (scole- 

 cesj to the wall of the upper portion of the small intestine. To the naked eye the parasites ap- 

 pear like long thin filaments. A detailed description is given by Shipley"". Those found by 

 the Investigation were identified by Jones'" whose account is the first record of this worm in 

 ruffed grouse in this country. 



Life Cycle and Dissemination. The life cycle of this parasite is unknown. Related tape- 

 worms of the gallinaceous birds reach infectivity in insects, particularly beetles. 



Pathogenicity. In one heavy infection with this tapeworm a small blood streaked area in 

 the duodenal mucosa was found where a great many scoleces were imbedded. A catarrhal in- 

 flammation of the upper portion of the small intestine was observed in another case where the 

 infection was severe. 



In practically all the other instances, however, the number of tapeworms in any single in- 

 testine was relatively few and no gross lesions were observed. 



No evidence was uncovered to establish that infection with tapeworms could kill ruffed 

 grouse. 



Incidence and Importance. Although this parasite was sometimes encountered in chicks it is 

 regarded as more typical in adults. In juvenile birds from three to nine months old, its inci- 

 dence was 1.6 per cent. Almost 10 per cent of the spring and summer adults were infected, 

 but less than 5 per cent of the fall and winter adults are thus parasitized. This tapeworm can 

 not be considered of importance as a pathogen in wild grouse on the basis of any observations 

 made during the Investigation. 



Cecal Worms (Heterakis bonasae) 



Distribution. This roundworm has been found in grouse in all three regions in New York. 



It is probable that many of the previous records of cecal worms from grouse, designated as 

 Heterakis gallinae. a common parasite of poultry, may actually represent records of grouse 

 cecal worms. It is therefore almost impossible to establish the distribution of this worm in 

 other hosts and in other regions. 



Description. Heterakis bonasae are small white worms measuring about V2 inch in length. 



