. Il campo Canadese-naturalista. 66 Il canadese Field-Naturalist [Vol. XLVll e molto spesso la parola "normale" ha ben poco senso a tutti. Esso copre le vaghe Impressioni soggettive di abbondanza in anni precedenti, le impressioni di ottenere più vaga come memoria recede. Ma la maggior parte delle persone che vivono fuori di porte e tra gli animali selvatici conservare una definita e probabilmente idea precisa dell ultimo anno di abbondanza, anche se esso non ha alcuna base quantitativa. Per questo motivo i raffronti di anno in anno consentono un record in esecuzione di qualsiasi ciclo di cospicua di essere tenuti al- se l'effettivo della scala verticale di ch

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. The Canadian field-naturalist. 66 The Canadian Field-Naturalist [Vol. XLVll and very often the word "usual" has very little meaning at all. It covers the vague subjective impressions of abundance in former years, the impressions getting vaguer as memory recedes. But most people who are living out of doors and among wild animals retain a definite and probably accurate idea of last year's abundance, even if it has no quantitative basis. For this reason comparisons from year to year enable a running record of any conspicuous cycle to be kept, al- though the actual vertical scale of change is not known. Comparisons at times of great scarcity are however not very easy, since chance patchiness of the population plays an important part in causing errors. The usefulness of this method must be judged by its results, which appear con- sistent with the statistical material that can be obtained for fur-bearers and with what we already expect from previous cycles. Estimates do have a certain value when comparing the maximum years of abundance or minimum years of scarcity, since there is in these instances a double compari- son with years before and after. Here memory often introduces errors in respect to exact dates, and double checking by different observers is desirable, unless notes have actually been kept at the time. It appears from data already in my possession that snowshoe rabbits reached their maximum abundance in most parts of northern and central Canada (in the conifer forest belt) about 1923-25, although some places in the far north-west were a year or so sooner. By 1927 there were very few places in Canada where rabbits abounded, and in most they were becoming extremely scarce. The population is now on the increase. The results of the 1931-32 enquiry are very clear-cut and prove that about 85-92% of the area covered by the network of observers had snowshoe rabbits on the increase, though not necessarily very abundant yet in all places. This result is sho

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