INDIVIDUALITY IN BIRDS. 231 



turn to favorite nesting-places, and autumn after 

 autumn migrants appear on favorite hunting 

 grounds : sometimes we feel sure that the robins 

 which return to the apple-tree, the bluebirds to 

 the box on the post, the orioles to the trailing 

 elm branch, are the same birds which built in 

 those spots in preceding summers ; but, as a rule, 

 positive evidence to this effect is lacking, and 

 our moral certainty is not capable of justification 

 to others. Generally the fact which makes us 

 most sure in our own minds that the birds in 

 question are old friends is some hint of individ- 

 uality on their part. They arrive on a fixed date 

 in the spring, build their nest in a particular 

 spot or in a particular way ; and the exactness 

 of the coincidence induces us to believe in indi- 

 viduality, rather than in the nature of all birds 

 of a species to do precisely the same thing under 

 similar circumstances. 



Where there is a wide variety in the nesting 

 ways of a species, the ability to fix upon certain 

 birds and feel confident of their identity is in- 

 creased. For example, I have known the song 

 sparrow to build upon the ground in the middle 

 of a dry field, or close to a tussock of grass at a 

 brookside ; a few inches from the ground, in a 

 pile of brush in a meadow ; in a dark pocket in 

 the hollow trunk of a willow ; two feet from the 

 ground, in a spruce ; and finally, eight feet above 



