. The Canadian field-naturalist. Fig. 3.^Having been pursued for ages by enemies such as hawks and coyotes, the squirrel has learned to provide his burrow entrances with safety devices in some form or other, one of which is shown in this illustration as a series of radiating troughs all leading to the burrow mouth. It is evident that a burrow mouth of this nature would be much easier found in times of great haste than a small round hole. Photo by William T. Shaw. Fig. 4.—As a rule the depth of the burrows is determined by some hard, underlying stratum into which they do not like to dig. The li
. The Canadian field-naturalist. Fig. 3.^Having been pursued for ages by enemies such as hawks and coyotes, the squirrel has learned to provide his burrow entrances with safety devices in some form or other, one of which is shown in this illustration as a series of radiating troughs all leading to the burrow mouth. It is evident that a burrow mouth of this nature would be much easier found in times of great haste than a small round hole. Photo by William T. Shaw. Fig. 4.—As a rule the depth of the burrows is determined by some hard, underlying stratum into which they do not like to dig. The lighter lower stratum here shown is of a hard, gritty, slightly cemented material. Photo by William T. Shaw. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ottawa Field-Naturalists' Club. Ottawa, Ottawa Field-Naturalists' Club
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Keywords: ., bookauthorottawafieldnaturalist, bookcentury1900, bookdecade1920
