8 BIRDS OF FIELD, FOREST AND PARK 



Of course the fast travelers cover these distances 

 in a much shorter time. The duration of the 

 spring migration is about eighty days, extend- 

 ing from early March to late May. In the 

 autumn the southward movement is made more 

 leisurely, extending from mid-August to late 

 November or early December. At this season 

 they seem in no hurry and many of the hardier 

 varieties linger until the real grip of winter is 

 felt. 



The northward journey is ended when the 

 bird has arrived in nesting grounds which are to 

 its liking. As a rule, members of a given variety 

 occupy the same general region, the area of 

 which varies greatly with the different species. 

 A few stragglers will venture farther than the 

 majority of the species, and a few laggards stay 

 somewhat behind the main body; but they 

 occupy pretty definite zones, except as the sum- 

 mer range is influenced by altitude. In moun- 

 tainous regions will be found nesting birds be- 

 longing to a species the main body of which 

 occupies a lower region, often much farther 

 north. For example, along the Allegheny and 

 Blue Ridge Mountains will be found as summer 

 residents a few varieties of which the great 

 majority are much farther north, perhaps in 

 northern New England or Canada. 



There have been lodged in the public mind 

 many interesting but highly erroneous beliefs 

 regarding the migration of birds, arising, no 

 doubt, from the mystery that attaches to their 

 sudden appearance in the spring and their 

 equally sudden departure in the fall. In Eng- 



