40 THE RAPTORIAL BIRDS OF IOWA 



or four different species) and the fact that a dead specimen comes 

 to hand only occasionally, it seems desirable to furnish a simple key 

 that will aid in identifying the more common species of Hawks and 

 Owls in our state. 



HOW TO MEASURE A BIRD. 



The total length of a bird (L.) is best obtained by laying the spec- 

 imen on its back upon a table, gently stretching its head backward. 

 Measure from the tip of the bill to the tip of the longest tail feather. 



The stretch of a bird is the distance from tip to tip of the wing 

 feathers. 



The tarsus extends from the base or insertion of the toes up to 

 the next joint, which is really the heel of the bird. (The knee of the 

 bird is usually hidden in the feathers.) 



The tail is measured from the insertion of the middle feather to 

 the tip of the longest feather. 



The wing is measured only from its "bend" to the tip of the long- 

 est primary. The "bend" is the one coming nearest to the neck when 

 the wing is folded. 



The primaries are the strong flying quills which spring from the 

 end joint, or hand, of the bird's wing. 



The length of the bill is taken with dividers along the "oilmen," 

 so as to give the distance in a straight line from the feathers at the 

 forehead to the tip of the upper mandible. 



KEY TO IOWA BIRDS OF PREY. 



A. Size large. Head naked or covered with short downy feathers ; 



bill rather long and hooked ; feet without sharp claws. Vul- 

 tures. One Iowa species. See No. 1, page 46. 



B. Size very large, large, medium or small. Head well feathered; 



bill short and strongly hooked ; eyes set in sides of head and 

 not facing forward. Plumage rather firm. Eagles, Hawks, 

 Kites and Falcons. See Key on page 41. 



C. Size large, medium or small. He^ad well feathered; bill short 



and strongly hooked; eyes facing forward, each surrounded 

 by a radiating circle of feathers. Plumage more or less soft 

 and fluffy. Owls. See Key on page 43. 



This key gives one or more characteristics of each species. The 

 Description of each species will furnish further points for identifica- 



