GREAT BLACK-HEADED GULL. 
301 
flat or grassy slope of these islets, never on the 
precipitous part of tho cliff, the eggs almost laid 
on the ground, or with a small portion of dried 
grass collected, Mr. Dunn writes, in Orkney and 
Shetland the Black-backed Gull “ builds its nest on 
small islands on stalks and the most inaccessible part 
of the rocks.” The parent birds defend their nest 
from all winged aggressors, but on the more fre- 
quented islands they seem to dread more the pre- 
sence of man, and soar high over head, showing 
their anxiety by their continued hoarse cackle, and 
only occasionally venturing a stoop at the ag- 
gressor. 
A specimen shot in the Firth of Forth in Fe- 
bruary, and sent for our uso by Mr. Fenton of 
Edinburgh, is in length between twenty-six and 
twenty-seven inches;* the extent of the wings, 
fully expanded, fivo feet; the wholo of the head, 
neck, rump, tail, under wing-covers, axillary fea- 
thers, and all the under parts of tho body, pure 
white ; the centre of the back and mantle deep 
greyish black, the quills nearly black ; the second- 
aries are tipped with white, forming a bar across 
the wing ; the first quill is tipped with white for 
nearly two inches, tho second for a shorter space, 
but having a narrow black bar interrupting it near 
the tip ; the third with a short white tip, and the 
fourth with a short white tip succeeded by black, 
again succeeded by a narrow clouded bar of greyish 
* Mr. Yarrell gives the male as thirty inches, the female 
as twenty-seven. 
