36 . August Brinkmann. 
Summary. 
Stimulated by the famous british investigations regarding the: 
Grouse in health and disease, the »Bergens Jæger- og Fiskerfor- 
ening« (The hunting and fishing club of Bergen) has made an 
attempt to find out the reasons for the fatal decrease of the Willow 
Grouse (Lagopus lagopus L) in Norway during the last few 
years. 
The present paper is part of this investigation and deals with 
the parasites of the intestine. 
The great difficulties experienced in obtaining sufficient ma- 
terial for a broad investigation have made it necessary to limit 
the investigation to the coast region (from Stavanger to Lofoten) 
and some of the central districts of the country, the eastern parts. 
not being represented in the material collected. 
As gamekeeping in the english sense is not in vogue in this. 
country, diseased and dead birds could not be obtained (all we 
know is, that a Jot of such birds have been reported last authum), 
therefore shot game only has been received to be investigated. The- 
material consists of about 120 birds collected in 1922 and 23. 
The methods of investigation have been the same as used 
by the zoologists of the Grouse comiteé. 
One of the most interesting facts brougth to ligth is, that the- 
Trichostrongylus pergracilis, the principal cause of the Grouse: 
disease in Great Britain, is not found in the Willow Grouse in 
this country; but the other dangerous parasite in the Red Grouse,. 
Eimeria avium, was found to be widely distributed in the Willow 
Grouse over great parts of the country. 
We found the parasite in 47 out of 112 birds examined. 
As one would expect from the nature of the material, the 
parasite is generally found in small numbers only, and the birds 
have evidently had an acute attack of the disease, which has deve-- 
då sne ka si 
