88 



The Canadian Field- Naturalist 



[Vol. XXXIII 



couraged, for he often has opportunities, resources, 

 and freedom to carry on important investigations 

 along side paths of knowledge which the govern- 

 ment investigator or professional naturalist is not 

 able to follow at his own inclination. The univer- 

 sities, colleges, and other schools, scientific surveys 

 and commissions, local museums and associations for 

 the protection of fish and game, ail have an oppor- 

 tunity to do good work for the country in this field. 



The value of detailed knowledge m fields which 

 have previously appeared seemingly trivial, has been 

 illustrated many times during the late war. As an 

 example of this, the pest of rats became exceedmgly 

 serious at the Bush Terminal of the port of New 

 York, the principal shipping point of the immense 

 amount of stores required for the American or 

 other expeditionary forces of the Allies. The use 

 of poison was impracticable around such great 

 quantities of feed stuffs, but by detailing field biol- 

 ogists to the Sanitary Corps and directing their field 

 experience to the problem of extermmating rats, 

 within a few months more than 50,000 rodent allies 

 of the enemy were accounted for, and it is esti- 

 mated that several million dollars worth of com- 

 missary and quartermaster stores were saved at a 

 critical time. 



The secretive and nocturnal habits of some species 

 of small mammals are responsible for so little being 

 known of them. They are correspondingly more 

 difficult to photograph than the birds. For this 

 reason field photographs of mammals — their nests, 

 runways, tracks, and general habitat, are particularly 

 desirable. Although the mammals as a rule are 

 more shy than the birds, and are less often seen ; 

 the larger animals on account of constant pursuit by 

 man for generations as objects of sport and of food, 

 and the smaller ones from fear of swooping birds 

 of prey, the presence of the mammal in a certain 

 region may be detected where the flying bird leaves 

 no trace. The pads of little paws on dusty roads 

 or the muddy brinks of pools or streams, or the 

 delicate tracery of tracks on the newly fallen snow, 

 leave a record, which though evanescent, may be 

 read and interpreted by the initiated, and lends in- 

 terest to walks in the great out-doors. 



In a field like this no one can cover every detail, 

 and the notes of many persons are needed for work- 

 ing out complete life-histories of any species, even 

 the commonest. A young observer may find out 

 something that was not known before and, in classic 

 phrase, "add something to the sum total of human 

 knowledge." As a suggestion to aspiring natur- 

 alists who are at a loss to know what to do or 

 how to begin, wc can not do better than quote from 

 Dr. 1 aylor's paper cited above: 



DATA THAT ARE IMPORTANT. 

 MEANS OF DETECTING PRESENCE OF PARTICULAR 

 SPECIES. ' 



"Tracks, distances between footfalls; differences 

 in tracks with different speeds or movements of 

 animal. 



Feces — abundance, shape, size, color, com- 

 position, place of deposit. 



Claw marks on trees, logs, or ground. 



Tooth marks on wood or bone. 



Wallows, dust baths, beds, forms, nests, shelters, 

 runways, holes, trails, cropped or harvested vegeta- 

 tion. 



HABITAT RELATIONS. 



Relation of soil, rocks, water, air, climate io 

 habits and distribution. 



Effects of unusual climatic conditions, as storms, 

 floods, and forest fires; degree and rapidity of re- 

 covery from disaster. 



Relation of animal populations to climatic cycles. 

 INTERRELATIONSHIPS OF SPECIES. 



Friends. 



Enemies — times of activity ; enemies in youth, 

 middle age, old age. 



Prey — modes of capture. 



Parasitic habits of species with reference to each 

 other. 



Parasites, internal and external. 



Bacteria and disease germs (carriage and trans- 

 mission of disease to stock or to mankind; species 

 as victims; decimation of animal populations; per- 

 iodicity of contagious diseases in animals; degree 

 and rapidity of recovery). 



Adaptations of animals to each other or to 

 plants. 



Competition between species, particularly be- 

 tween those closely related. 



TIMES OF ACTIVITY. 



Hours of beginning and cessation of daily 

 activity. 



Unusual activity, as of diurnal species at night 

 or of the nocturnal by day. 



MIGRATION. 



Local or general movements before and after 

 breeding. 



Dates of appearance and disappearance (espec- 

 ially of bats). 



Extent and direction of movements, local and 

 general. 



Causes of migration — food supply, climatic, 

 physiological. 



Unusual migratory movements, as the spasmodic 

 irruptions of len^mings, with causes therefor. 

 HIBERNATION AND ESTIVATION. 



Date of entering upon and emerging from hiber- 

 nation. 



