of grouse collected from several areas of the province showed the food requirements 

 at different seasons of the year. As a supplement to the field research, studies of 

 grouse nutrition were initiated in co-operation with the Ontario Veterinary College 

 at Guelph. Planning was completed for experimental improvements, by forest 

 clearing, fertilization and planting of preferred foods, in grouse range in an effort 

 to improve productivity and hunter success. 



Research was continued on a method for measuring productivity of Canada 

 geese breeding in the Hudson Bay Lowlands. The results will be used to set more 

 reahstic autumn bag limits for hunters in the Mississippi Fly way. The success of 

 this method, which uses low-level aerial photographs of young and adult geese, is 

 very difficult to assess at the present time since large segments of the population 

 in Ontario may be non-breeding birds. Work is continuing on the analyses of 

 results in co-operation with the U.S. Fish and Wildlife Service and a member of 

 the Illinois Natural History Survey. Biologists from Ontario co-operated with those 

 from Manitoba and Quebec to extend this survey into the latter two provinces. 



Furbearers 



It has long been recognized that instability in production of furs has had an 

 adverse effect on the livelihood of trappers. Furbearer research in Ontario is 

 directed toward an understanding of the factors which affect populations of beaver, 

 otter and mink, among other furbearing animals, with the objective of moderating 

 the fluctuations in numbers. 



Research on beaver in the Patricia Districts of northern Ontario and on 

 Michipicoten Island have shown that populations can reach very high densities 

 often, as in northern Ontario, in the relatively short time of three or four years. 

 These studies have also shown that excessive trapping pressure is required to 

 deplete such populations. High beaver populations in central Ontario have not 

 been affected by ordinary trapping pressure. We anticipate that factors, other than 

 trapping, will eventually decimate these populations and continuing studies are 

 assessing the importance of depleted food supplies, disease, predation and adverse 

 weather. A technique for ageing beaver by their teeth development, which had its 

 origin in the Research Branch, has now been perfected in co-operation with a 

 member of the staff of the Nova Scotia Department of Lands and Forests. 



Wildlife Diseases and Parasites 



The effects of most diseases and parasites of wildlife in Ontario are as yet not 

 well known. Research on diseases and parasites is providing an understanding of 

 their occurrences, distribution and importance as regulators of animal numbers 

 and of their possible implications in domestic animal and human populations. 



Included in the responsibilities of this research unit is a diagnostic service for 

 field staffs who receive specimens and inquiries from the public. During the year, 

 116 specimens of birds and mammals were autopsied and the results reported to 

 the Districts concerned. There was no evidence of any diseases or parasites (except 

 rabies which has been present since 1954) reaching epizootic proportions in any 

 wildlife species. Rabies in foxes and skunks continued at a relatively lower level 

 throughout central and southern Ontario and research on the relationship between 

 the incidence of rabies and the density of fox populations was continued. A single 

 isolated case of tularemia was identified in a beaver from Gogama but there was 

 no indication that beaver population in this area were threatened. 



Studies of the frequency of occurrence, distribution and effects of kidney worm 



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