FAM. XXIX. HAWKS, EAGLES, ETC. 207 



24. White Gyrfalcon (353. Fdlco isldndus). — This arctic 

 falcon, which has been found in northern Maine, is, in good 

 phmiage, a slightly mottled white all over. There is apt to be 

 more or less of brownish and grayish in bars or streaks on the 

 shoulders, central tail feathers, and head. 



Length, 22 ; wing, 16 ; tail, 0^ ; tarsus, 2| ; cuhnen, 1. Arctic region.s, 

 wandering soutli to nortliern Maine. 



25. Gray Gyrfalcon (354. Fdlco rusticolus). — A northern fal- 

 con, Avith the upper parts, including the tail, blackish-gray, 

 barred with buffy-white, and the 

 under parts white, blotched and 

 streaked with blackish, but the 

 under tail coverts are barred Avitli 

 brownish. 



Length, 20-25 ; wing, 13J-16^ ; tail, 

 8-10 ; tarsus, 2\ ; culnien, 1. Arctic 

 regions, straggling south in winter to 

 the northern United States. The Gyr- 

 falcon (354*. F. r. (jyrfalco) of the Arctic 

 regions has been found as far south in 

 winter as Rhode Island. It is similar to 

 the gray gyrfalcon, but lacks the regular 

 bars of the upper parts ; sometimes there 

 are no bars at all ; the under parts are 

 always heavily streaked with blackish. 

 The Black Gyrfalcon (354^. F. r. obso- 

 letus) of Labrador is casually found as 



far south as Long Island. This, as its q^^^ Gyrfalcon 



common name indicates, is a very dark- 

 colored gyrfalcon. The upper and lower parts are an unbarred slaty- 

 black ; even the tail is nearly unbarred. All the gyrfalcons are rare in 

 the United States, 



26. Prairie Falcon (355. Fdlco me.vic(inus). — A bold, grace- 

 ful, low-flying, western, grayish-brown falcon, with the lower 

 parts white, streaked and spotted with the color of the back. 

 The primaries and the inner webs of all but the middle tail 

 feathers are blotched or barred with buffy. The young has 

 buffy margins to the feathers of the upper parts. This, as its 



