214 CONSERVATION OF CANADIAN WILD LIFE 
feed upon the combs and nests of the bees. The number of 
field-mice near villages and small towns is largely dependent 
upon the number of cats, with the result that bumble-bees 
are said to be more abundant near such places, with a con- 
sequent increase in the clover crop. 
When we study these phenomena as they occur in our 
wild life, the dependence of the larger animals upon the 
abundance of the smaller is very marked, and we discover 
the significance of the well-known periodical increase and 
decrease in the prevalence of many of the well-known mem- 
bers of our wild life. 
At the bottom of the scale are the numerous species of 
mice and voles, which constitute the food of so many of 
the large and small predatory animals. The observations 
of Cabot* on the rise and fall in the abundance of mice, and 
the effect on the larger animals, are of great interest in this 
connection, as they were made in the same region, namely, 
northern Labrador and the interior of Ungava peninsula, 
and during consecutive years. When he first visited the 
region in 1903 mice were not noticeably abundant. Cari- 
bou had been abundant through the winter, and in early 
July passed north in large numbers, close to the coast. 
There were some of the large predatory birds, such as falcons. 
Few ptarmigan were seen. Foxes, the most important fur- 
bearers of the region, were fairly abundant. By 1904 there 
had been a noticeable increase in the numbers of mice. 
Hawks were more numerous. Ptarmigan were fairly nu- 
merous. Many tracks of wolves were seen, chiefly along 
the river banks, where mice occur. A wolverene that was 
killed was full of mice. Hawks and owls occurred inland. 
In 1905 the mice reached their maximum abundance. 
Cabot states: ‘‘Sometimes two at a time could be seen in 
the daylight. Low twigs and all small growth were riddled 
by them. There was a tattered aspect about the moss and 
* William B. Cabot, “In Northern Labrador,” Boston, 1912. 
