FIELD STUDY 39 



sired familiarity. For the study of the behavior 

 of the animals concerned many observations can 

 be made by remaining quiet, carefully concealed, 

 and recording all observations. This method is 

 particularly applicable to animals which live in 

 exposed places, such as many insects, birds, and 

 mammals. For other kinds, only indirect methods 

 of observation are possible, or only when under 

 controlled conditions. For the indirect methods of 

 observation many forms of traps have been devised, 

 traps not intended merely to receive the dead animal, 

 but those also which will secure the animal and 

 reveal something of its behavior. For the study of 

 the habits and behavior of such animals as live in 

 the soil or under bark, etc., both extensive collecting 

 and examination of the animals in vivaria will also 

 be necessary. 



Fortunately for the student of mammals, birds, and 

 fishes we have excellent guides for the technique of 

 study and photographing of individual and associated 

 kinds in the works of Kearton (1907), Chapman 

 (1900), Herrick (1905), and Reighard (1908). It 

 is very desirable that these methods be applied to 

 the interrelations among the animals of an associa- 

 tion. The student of behavior in nature has much 

 to learn from many excellent studies of animal 

 behavior which have been carried on in recent years 

 by laboratory students. Fortunately the line be- 

 tween these two methods of study is breaking down to 

 the mutual advantage of each. The border line 

 between these two methods will give excellent re- 



