Biology_of_Mustelids_Vol_1.pdf

180.
The numbers of "mice" in the fourth quarter of that year were rated by them
as follows: extremely many - 33.3% of replies; many - 41.7%; average
16.7% and few 8.3%. When making comparison with the same period of
the preceding year, replies stated: more - 53.8%, just as many - 36.5%
and fewer 7.7%.
The fluctuations in the numbers of the ermine should be related
not only to changes in the rate of infection by Skrjabingylus nasicola, but
also to food supplies, which remain the chief regulating factor.
Under
certain circumstances skrjabingylosis may have a profound influence on the
dynamics of the ermine stock, and in our view, this factor explains the
situations sometimes observed, where, despite relatively favourable supplies
of food, ermine numbers show a decline, instead of the expected small rise
or stabilisation.
In the lean years skrjabingylosis makes a bad situation
even worse, such as happened, for example, in the Vologod Region in 1940.
The catastrophic decline in the ermine stock at the time of the 1940-41
hunting season must be attributed to the simultaneous action on the population
of two unfavourable factors:
starvation, as a result of the almost
total absence of small rodents in 1939-40, and heavy invasion by Skrjabingy­
Ius nasicola (on average 24 specimens per ermine).
Even less is known about the infectious diseases which from time
to time take a heavy toll among the stock of game birds and animals.
study of epizoatics of wild animals is important not only from the economic
point of view, but also in the interests of national health, since certain
of these diseases are also infectious to man, such as tularaemia.
The
reservoirs and main vectors of the tularaemia bacterium are murine rodents,
so medical workers and biologists are concentrating on this group of
mammals.
Yet the list of wild animals susceptible in various degrees to
tularaemia is long and varied, including certain amphibians, reptiles,
birds and many mammals belonging to different orders.
The VIEM tularaemia