524 



THE PRAIKIE FALCON. 



white, immaculate on throat, elsewhere marked with brownish gray of same shade 

 as hack, narrowh and distinctly on breast, broadly on sides and flanks, where 

 falling into bars, sjiarsely on crissum, coalescing in maxillary region into broad 

 must.-iche. I'.ill dark bluish changing to yellow at base and on much of lower 

 mandible ; feet yellow : iris brown. Voiiiuj birds are darker above with feathers 

 distinctly margined with light rusty, and their underparts are tinged with pale 

 buffy and more broadly streaked : — the younger the bird the richer the coloration. 

 Dozimy \oiiiui. pure white. Length of adult male: 17.00-18.00 (431.8-457.2); 

 wing 11.50-12.50 (292.1-317.5) ; tail 6.50-7.50 ( 165.1-190.5) ; culmen .75 (19.1) ; 

 tarsus 2.00 (50.8). .Adult female, length: 18.50-20.00 (469.9-508); wing 13.25- 

 14.25 (336.6-362); tail 8.00-9.00 (203.2-22S.6) : culmen .87 (22.1); tarsus 2.2^ 



(57-2).'^ 



Recognition Marks. — Crow size; iiowerful. easy flight; light lirowuish gray 

 coloration with size distinguishes it from any related local species, especially the 

 darker Peregrine : varied screaming cries. 



Nesting. — Xcst: a ledge or cranny of clift'; usually luimarked. occasionally 

 1)muided bv a few sticks. Egijs: 4 or 5, creamy buff or pale vinaceous, heavily 

 sprinkled or. rarely, stained and blotched with cinnamon. Av. size. 2.i8xT.6o 

 (55.4x40.6). Season: ALay 1-15 : one lirood. 



General Range. — Western I'nited States cast to eastern border of Creat 

 Plains passing northern border into soiUliern llrilish Columbia. .Mberta. and 

 Assiiiiboia ; south into Mexico. 



Range in Washington. — Common summer resideiU in Lpper Sonoran and 

 Transition life-zones of eastern \\'ashiugton ; rare or casual west of the Cascades. 



Authorities. — l-'aico f'olyaijnis. Cassin, "Illustrations" (' 185^1), j). 88 

 ("Puget's Sound" ). 



Specimens. — P'. 1^'rov. C. 



IN SPITE of the fact that the Prairie 

 Falcon is really one of the commonest rap- 

 tors in the West, its discovery within the 

 / ^ United States was not reported till i<S53^. 



and it long remained a rare and little-known 

 liird. Coucs in 1874'' confessed to having 

 .seen but one of them: and a set of eggs 

 taken in i860 by Dr. Hayden in the W^ind 

 Ri\er Mciunlains of \\''yoming \vas for some 

 vears unique. In this respect the history 

 (if the Prairie F'alcon shows analogy to that 

 of certain sea fowl. Birds that have been 

 known \ag"uel\' for \-ears as inhabitants of 

 Photo by the Author, the opeii oceau, may not be ftdly known 

 A-wiNG. until their breeding haunts are discovered, — 



a. Cassin, B. of Cat. and Texas, I., p. 88, P). i6. 



b. Birds of the Nortliwcst (1874). p. 346. 



