FALCONID^ — THE FALCONS. 299 



fine rufous, the former with longitudinal spots, the latter with transverse 

 bars, of blackish. Secondaries and primaries plumbeous, the latter with 

 a hoary cast. Tail white, washed with pale ash, and more or less stained 

 along the edges of the feathers (longitudinally) with light rufous; some- 

 times with a badly defined indication of a dusky subterminal bar. Young. 

 Above dark grayish-brown, with only the borders of the feathers rufous 

 or ochraceous; tibiae white, with sparse transverse spots of dark brown. 

 Tail white only on basal third, and on inner webs, the remaining por- 

 tion brownish-ashy, with several more or less distinct darker bands. Hab. 

 Western North America, from Arizona, California, and Oregon, east to the 

 Great Plains. 



2. A. lagopus. Wing, 15.75-18.20; tail, 8.70-10.50; culmen, .80-1.00; 

 tarsus, 2.30-2.80; middle toe, 1.30-1.50. Bill narrow, compressed; be- 

 neath more or less spotted with dusky, which usually predominates ; breast 

 with large spots of dusky ; no rufous on upper parts, nor on tibite. Adult. 

 Whitish, with transverse dusky spots. On the lower parts, the dusky spots or 

 cloudings, largest and most suffused anteriorly (on the jugulum and breast). 

 Terminal portion of the tail with several irregular dusky bands. (Sometimes 

 almost entirely black, varying in shade from a brownish to a carbonaceous 

 tint!) Young. Above grayish-brown, longitudinally spotted with dusky, 

 and more or less edged with pale ochraceous, or rusty whitish. Beneath 

 ochraceous-white, with the spots largest and most suffused posteriorly, form- 

 ing a wide, more or less continuous belt across the abdomen ; markings on 

 the jugulum and breast longitudinal. Terminal portion of the tail without 

 transverse bars. 



Spots on the jugulum, in the adult, suffused into a nearly uniform 

 patch. Never melanistic (?). Hah. Europe . . . var. lagopus.^ 



Spots on the jugulum, in the adult, scattered. Frequently melanistic. 

 Uab. North America . . . . . . var. sancti-johannis. 



1 ArcMbuteo lagopus (Brunn.), Geay. Falco lagopus, Brunn. Orn. Bor. p. 4, sp. 15 (1764) ; 

 Penn., Gmel., Lath., Siemss., Daud., Shaw, Naum., Meyer. Bufco lagoims, Steph. et 

 AucT. Butaetcs lago2ms, Bonap., Gray, Bailly, Morr., Reich. ArcMbuteo lagojms, Gray, 

 Gen. B. (ed. 2), p. 3 ; 1841, et AucT. (Not of American writers, nor when used for the Ameri- 

 can bird !) Hab. North and Central Europe ; Northern Africa. 



A comparison of the American birds with series of sixteen European specimens shoAvs constant 

 differences in the birds of the two continents, — quite enough to establish a difference of race, 

 although not of specific value. The European bird is much the darker beneath, the blackish- 

 brown spots on jugulum and breast being blended, or suffused, so as to give the predominating 

 tint to this region. 



These differences, though constant and quite appreciable on comparison, are very slight, while 

 the proportions are about the same. A young specimen of the European style differs from Ameri- 

 can in entire absence of rufous tinge to white of head, neck, and lower parts, less complete band 

 across the abdomen, immaculate white ear-coverts, cheeks, and throat ; the tibite and tarsi are 

 also much more thickly spotted than in the American young ; there is also more white on base 

 of outer surface of primaries. 



List of Specimetis examined. — Nat. Mus., 6; Philad. Acad., 8 ; Bost. Soc, 2. Total, 16. 



Measurements. — $ . Wing, 16.00; tail, 8.79; culmen, .80; tarsus, 2.30; middle toe, 1.30. 

 Specimens, 1. 9. Wing, 18.20; tail, 9.75; culmen, .95; tarsus, 2.60; middle toe, 1.50, 

 Specimens, 1. 



