ON BIRDS FROM THE NETHERLANDS. 205 
Microfalco gyrfalco islandus (Briiunich). 
(Plate 2). 
The white gyr-faleon, shot 7 December 1909 near Rijs- 
bergen, Noord-Brabant, which I have mentioned on page 
176 of this volume, is now, I am glad to state here, in 
the possession of our Museum. 
In the last of March of this year Jhr. W. C. van Heurn, 
student of Zoology, told me, that Mr. C. J. Bosman at 
Scheveningen was in the possession of a nearly white 
bird of prey, shot in our country. Mr. Bosman kindly 
allowed me to see the bird; I was not less astonished to 
see a true white gyr-falcon, which species till yet had not 
been observed in the Netherlands. 
According to the taxidermist who has stuffed the bird, 
it should be a female, but its measurements prove that it 
is certainly a male, and judging from its plumage, a 
rather young male. The measurements are: wing 390, tail 
220, culmen (from cere to tip) 21, tarso-metatarsus 58, 
middle toe with claw 75 mm. The bill is yellowish grey 
with dark tip, the cere and the feet greyish horn. 
Head and sides of face white with dark brown longitu- 
dinal streaks; upper surface greyish brown with white 
spots and white margins to the feathers. Centre pair of 
tailfeathers white with 10 dark brown cross-bands; other 
tailfeathers white with irregular small spots of dark brown 
at the outer webs. Chin and throat white; breast, vent 
and flanks white with drop-shaped spots of dark brown; 
thighs white with some longitudinal streaks of dark brown; 
under tailcoverts white. Under wingcoverts white with 
dark brown longitudinal streaks, the greater ones with 
dark brown shaft-stripes. 
The nomenclature and synonymy of the three forms of 
gyr-falcon, which occur in Northern Europe, I let follow here: 
Hierofalco gyrfalco (L.). 
Falco gyrfaleo Linnaeus, Syst. Nat. Ed. X, I, 1758, p. 91. — Id. 
Ed. XII, I, 1766, p. 130. — Schlegel, Vog. v. Nederl. 1854—58, 
Notes from the Leyden Museum, Vol. XXXII. 
