90 A FIELD GUIDE IN NATURE-STUDY 



XX Nearly one and one-half times as large 

 as a robin 

 Y All of head and throat dark 



a Bill red, under parts suffused 



with pink Franklin's Gul 



aa Bill black, under parts white Bonaparte's Gull 



YY Top of head black (in winter crown 

 white) 

 a Feet and bill orange; under 



parts white Forster's Tern 



aa Feet and bill red; breast and 



belly pale gray Common Tern 



XXX About as long as a robin, slender; belly 



yellow, feet orange Least Tern 



OO Bird dark all over 



X Body black, wings dark, small Black Tern 



XX Body and wings dark, large 



Young of Herring and Ring-billed Gulls (see p. 89) 

 II Feet not webbed, held up close to the body in 

 flight; usually seen over the land (except fish 

 hawk), flying at a considerable height and in 

 wide sweeping curves; marsh hawk flies low and 

 some of the hawks fly in straight lines, but all 

 are usually easily recognized as hawks, their 

 flight is so swift 

 O Head without feathers 



X Red head Turkey Buzzard 



XX Black head Black Vulture 



OO Head feathered 



X Nearly 3 ft. long 



Y Head white; leg not feathered clear 



down to toes Bald Eagle 



YY Head not white; leg feathered to 



toes Golden Eagle 



XX 2 ft. or less in length 



Y Tail without cross-bars or bands 

 (tip may be white) (the black band 

 on red-tailed hawk does not show 

 clearly from below) 

 a Under parts streaked 



Red-shouldered Hawk, immature 

 aa Under parts unstreaked 

 o A band across the belly 



Rough-legged Hawk, immature 



