NON-INDIGENOUS BRITISH BIRDS. 127 



Family FALCONID^. Genus Hierofalco. 



Sub-family FALCONINyE. 



SCANDINAVIAN JER-FALCON. 



Hierofalco gyrfalco {Linnceus). 



(British : Rare nomadic winter migrant.) 



Single Brooded. Laying season, April and May. 



Breeding area : North-western Palaearctic region, 

 so far as is at present known. The Scandinavian Jer- 

 Falcon breeds on the fells of Norway and Sweden, 

 especially in the Norwegian province of Fin mark. 

 Whether this form of Jer-Falcon inhabits the northern 

 portions of Russia and Siberia seems by no means clear. 

 It may ultimately be found to do so, and to interbreed 

 with H. candicans in the far east, as it appears to do 

 with H. islmidus in the west. 



Breeding habits : With the exception of the obser- 

 vations made by Wolley and the Swedish naturalist 

 Collett, we have little information concerning the nesting 

 habits of the Scandinavian Jer-Falcon. Even within 

 the limits of this restricted observation there is much 

 evidence of a conflicting nature, which seems to suggest 

 that the bird is well able to adapt itself to local circum- 

 stances. Whether this Falcon ever builds an elaborate 

 nest for itself is by no means clear. Collet says that 

 the bird almost always builds a nest at the top of a 

 large fir tree ; and an (tgg was brought to Wolley with 

 the information that it had been taken from a nest in a 

 tree. On the other hand, Wolley 's personal experience 

 was to find the bird breeding on a ledge of the rocks, 

 he describing the nests as very flat and large, made of 

 dead, barkless sticks, and lined with dry grass, or com- 

 posed of fresh sticks, lined with willow twigs and sedge ; 



