INTRODUCTION. 
XXXV 
17. Falco candicans . . . . , . . . . . . . Vol. I. PI. XIII, 
Greenland Falcon. 
This species inhabits the icy regions of Greenland, Hudson’s Bay, and other parts of Arctic America, and 
is less frequently seen in the British Islands in the adult state than the F. tslandm, from which it is distin- 
guished by the extreme whiteness of its plumage, and by the young being lightly coloured from the nest. 
18. Falco candicans ........... . Vol. I. PI. XIV. 
Greenland Falcon (dark race). 
My plate represents a supposed dark race of the preceding species ; but as the strongly defined marks on 
the back vary considerably in different Individuals, and the tail-feathers differ still more so, some being 
wholly white, others barred, and others, again, having irregular dark markings, I am induced to regard these 
darkly marked birds as the result of a cross between F. islandus and F. candicans. The young appear 
to be lightly coloured from the nest ; but a considerable difference takes place at the first moult, when the 
feathers of the back are ornamented with long and broad blotches, offering a strong contrast to the narrow 
lunate cross markings of the old bird. I have been induced to give two figures of these unusually marked 
birds. 
19. Falco candicans ............ Vol. I. PI. XV. 
Greenland Falcon (dark race, young). 
Lord Caivdor’s bird, now in the British Museum, from which my figure of the Gyr Falcon in the ‘ Birds 
of Europe,’ and Mr. Yarrell’s in his ‘British Birds,’ were taken, is a young specimen of this race ; and it is 
in this stage that most of the Individuals are found with us. 
20. Falco gyrf.\lco ........... . Vol. I. PI. XVI. 
Norwegian or Gyr Falcon. 
The true Gyr Falcon of Norway, Sweden, Finland, and Western Russia is a smaller bird than the three 
preceding ; and both the adult and young are darker in colour. As yet, it has not been found in the British 
Islands, although its native country is so near at hand. The plate has been given to show the differences 
which exist among these northern Falcons, to which Professor Kaup has applied the separate generic 
appellation of Hierofalco. 
