lOy NORTH AMKUrCAN TiinD,^. 



1. Adult. TTppcr piirts, pxi'cpiiiip; licinl and iiock, wiili transvorso 

 crcscoiitic liiiis of ilaik |)liiiiib('oiis ; lower parts iinniacuhitr, or 

 else willioiit WfU-di'tiiii'il inarUiiifrs, Youtig. U])por parts with 

 li)iiij:iliiililinl stripes of dark pliiiiihcous ; lower parts usually coii- 

 spiciiously striped. Ilab, Greenland (in the lirecding-senson) ; in 

 winter, oeeasionally wandering into the iK)rtliern portions of 

 Europe and Xorth Anieriea ..... var. can di ra n n , 



Lower tail-coverts always with inarkiiifrs. A tinge of ashy-blue more or 

 le.«.s prevalent aliove. Young dusky ahove. 



Head and neek aliove abruplly lighter than the haek. Young |)laiii 

 prayish-lirown above, with eons|iieuous whitish borders to the feathers. 



2. Adull. Upper parts white, passing into bluish posteriorly ; 

 everywhere (exeept on head and neek) with sharply defnied, 

 transverse (not ere.seentie, liut eontinuous) bars of dark pluinbeon.s. 

 Abdomen and Hanks with transverse spots of the same. Young 

 without irregular light mottling to the plumage above, and with 

 broad longitudinal stripes beneath. Ilab. leeland and Southern 

 Greenland, in the breed i ng-sea.s(jn ; in winter, south into North- 

 eastern United States and Northern Europe. , var. i iilandicu x. 



Head and neck above abruptly darker than the back. Young (of var. 

 sacer) variegated grayish-brown above, without light borders to the 

 feathers. 



3. Adull. Top of the head .streaked with whiti.sh; back with 

 sharply defined, eontinuous, narrow transverse bar.«, of creamy- 

 white. Hah. Interior regions of Continental Arctic America 

 (Slave Lake, Yukon, and McKenzie Hiver district) , . var. .lacer. 



4. Adult. Top of head not streaked with whitish ; back without 

 sharply defined bars of the same. Ilab. Continental Arctic Em'ojie 

 (Scaixlinavia) and Siberia. Migrating south, in winter, to Bengal 

 (Hardwiekc) var. (jyrfalcn.^ 



b. Lower parts with dusky predominating, or wholly dusky. 



;■). Adult. Almost entirely dusky, without well-defined markings 

 anywhere. Ilab. Littoral regions of the Hudson Bay Territory 



and Labrador . var. la b r ado ra. 



2. P. lanarius. AVing, 11.50- IG.OO; tail, G.G0-9..")0; culmen, .70-1.00; 

 tarsus, 1.90 -2.40; middle toe, l.Gr)-2.00. Ground-color varying from pale 

 grayish-phmd)eous to dark sepia-brown ; beneath white, with sparse markings, 

 these coalesced into a broken patch on the llaidvs. Adult. Above oli.scnrely 

 barred transversely with pale a.shy and brownish-du.sky, the former prevailing 

 posteriorly, the latter anteriorly ; a lighter nuchal band. Spots on the sides and 

 fianks transverse. Yonnij. Above brown, varying from grayish-drab to dark 

 sepia, the feathers usually bordered with paler (rusty in youngest individuals) ; 

 markings beneath all longitudinal. 



a. Outer webs of tail-feathers with large well-delined light spots ; outer 

 webs of the primaries sometimes with light spots on the basal portion ; 



' Fnico (fyr/ako, vav. tvjrfiiko (Lisn.). Falco gyrfalco, Linn. S. N. 1701), p. 130. — fijir.!,. S. N. 

 ST.*). — Snii.KO. Iicv. Crit. M, Tr. do Fauo. pi. iii ; V. van Ncdcrl. Vog. ]ils. iii and iv. — 

 N'Air.M. Vng. pi. ceixei. Ilierofaho giirfako, Selli.EO. Bon.m'. Hev. Zool. 1854, 535. — Newton, 

 Oiithcca WoUcyana, 1, 87, pi. p. F. f/i/rfdlco nonr.f/icus, Woi.i,i;v. Falco gijr/alco nonvegicus, 

 S<'lli,KO. Mils. Pays-Uas, 18(52, 12. Fulco amdiaim, var. 7, Blas. 



Wing, 13.00 -U.,')0 ; tail, 9.30 ; culmen, .98 ; tarsus, 2.50 ; niiddlo too, 1.92. 



