Figure 4.— A nearly fledged young liald f;ii;U'. St-ney National Wildlife Refuge, Mich. 

 Flexing its wings, it is almost ready to take its first short flight. The character- 

 istic flat-topped nest of sticks is lined with finer material and is located 65 feet 

 from the ground in a red pine. ( Photograph by 0. J. Henry. ) 



As in most birds of prey, the 

 female bald eagle is larger and 

 heavier than the male. Friedmann 

 (1950) stated that the average wing 

 length of 16 adult male bald eagles 

 from Southern United States was 

 529.2 millimeters (20.83 inches) and 

 that of 29 adult male northern bald 

 eagles, 588.6 mm. (23.18 in.) . Com- 

 parable measurements for the wings 



of adult females were 526.5 mm. 

 (22.70 in.) in 11 southern birds and 

 640.2 mm. (25.21 in.) in 42 Alaskan 

 birds. Similar differences were dis- 

 closed in the measurements of the 

 tail, bill, and other features of the 

 two groups of birds. 



In the course of Alaskan field- 

 w^ork, the senior author recorded 

 the dimensions and weights of 108 



11 



