228 CONSERVATION OF CANADIAN WILD LIFE 
migration is not a cause of the periodic fluctuation is proved 
by a study of the total fur returns for the whole territory 
covered by the Hudson’s Bay Company. These figures 
show that while local migratory movements may occur, the 
periodic fluctuations are general for the entire territory, 
and occur with remarkable regularity. 
According to the fur returns of the Hudson’s Bay Com- 
pany the years in which marten was most abundant were: 
1827, 1837, 1846-47, 1856, 1866, 1875, 1886, 1895, 1903. 
The periodic fluctuations occurred in cycles of 
10, 9, 10, 10, 9, 11, 9 and 8 years, 
giving an average periodic cycle of 9.5 years. 
If we compare the years of maximum abundance of the 
marten with those of the rabbit we find that the years of 
maximum marten abundance in 1846, 1856, and 1866 oc- 
curred one year after the maximum rabbit abundance, the 
years of maximum abundance in 1875, 1886, 1895, and 
1903 preceded by two years the years of maximum rabbit 
abundance, although they occurred during the period when 
rabbits in the aggregate were on the increase, and had 
almost attained the maximum. 
A study of the chart illustrating the fluctuations of mar- 
ten reveals another interesting feature, namely, the absence 
from about 1875 onwards of a very marked regularity of the 
curves of increase and decrease, such as occurred previous to 
that year. This, I believe, is accounted for by the intro- 
duction of artificial factors of various kinds which affect 
the marten population in different parts of the country, 
and I am inclined to believe that the greater destruction of 
the forests by fire and other causes, which has undoubtedly 
occurred since 1875, has been mainly responsible for this 
very noticeable change in the fluctuation of this species of 
fur-bearer. 
