L>S4 LIFE-HISTORIES OF BIRDS 



probable that these birds might now be nesting within 

 the limits of Philadelphia. 



The nest is ordinarily built upon the summit of tall trees. 

 the pine and balsam poplar being not unfrequently chosen, 

 often at an elevation of sixty feet. Occasionally, the tree 

 selected, stands in the midst of a swamp, and sometimes 

 not very remote from a public highway. The size of the 

 trunk, and its lack of branches, sometimes render the nest 

 almost inaccessible. But this circumstance is purely acci- 

 dental. Where there are no trees of convenient height, as 

 along the rocky shores of California, the Bald Eagle avails 

 itself of rocky cliffs, for nidificating purposes. The period 

 of nesting depends in a great measure upon climatic condi- 

 tions. In Maine, the time is later than in the Southern 

 States, whilst in the Arctic regions, owing to the ponds 

 and rivers being ice-bound, and where the birds are only 

 summer residents, this business does not take place until 

 much later. 



Nesting often takes place as early as the beginning of 

 January, sometimes as late as the early part of March. 

 Near the Damariscotta River in Maine, eggs are some- 

 times laid as early as March 13, when the ground is covered 

 with snow to a great depth, and when the thermometer 

 points to a temperature often considerably below zero. 



The nest is ordinarily a bulky affair. It is composed of 

 several layers of large sticks, from three to five feet in length, 

 and from an inch to nearly two inches in thickness. The 

 interior is lined with weeds, dry leaves, tufts of grass. 

 mosses, and lichens. The same nest is usually occupied 

 for several successive years, and is the frequent place of 

 resort throughout the entire year. In the Anderson River 

 district, according to Mr. Macfarlane, the nests are placed 

 on tall trees, close by the river-banks. They are constructed 

 of decayed branches and dry sticks, externally, and are va- 

 riously lined with hay, moss, deer's hair, and other materi- 

 als of a like nature. 



