BRITISH BIRDS OF FASTEST FLIGHT 39 
cans). The gyrfalcon is a very rare visitor here, 
two recorded specimens only having been ob- 
tained here and one of these is doubtful. The 
Iceland falcon is a rare visitor also, although 
identified examples have been obtained here from 
time to time. The Greenland falcon is an irregular 
winter and spring visitor, but there are more 
recorded instances of this species than in the case 
of the Iceland falcon. The former bird, the 
prevailing ground colour of which is white, is the 
most beautiful of all birds of prey. By some 
authorities it is considered merely a race of the 
Iceland falcon, which it resembles in size and 
habits. The eggs of the two birds resemble one 
another. All these Northern falcons are about 
the same size and larger than, though very 
similar in structure to, the peregrine falcon. 
Speaking generally, the difference in length is 
about 5 inches, in wing 2 inches. They have 
been very highly valued in Europe for hawking, 
and, as would be expected from their superior 
size and similar structure, are undoubtedly faster 
than peregrines. 
Writing in the Field for March 15, 1923, 
Major Radclyffe says : ^ 
1 See also the letter of Mr, H. G. Hurrell in the Field for March 8, 1923. 
