34 BRITISH BIRDS. 
trees, on the rocks, and on the ground. At last the loud ¢sip of the Cross- 
bills is heard, and a small compact party of perhaps a dozen birds, con- 
spicuous amongst the Thrushes by their smaller size and shorter tails, pass 
by, and you may remark the brick-red of the rumps of many of them, 
which glisten in the sun as they fy away. However tame the Crossbills 
may be in our country in winter (and I have approached them within a 
few feet and watched them feeding undisturbed), in the Engadine in their 
summer-quarters they are wild enough. They associate with the Thrushes 
as Starlings do with Rooks, in a flock within a flock, and like them cover 
square yards of ground, whilst their companions spread over acres. Some- 
times I saw an isolated male or two flying over the trees with rapid steady 
flight, but broken by continual short pauses, giving it an undulatory 
character. I found them extremely shy; and although I could slowly 
follow a flock of Thrushes for a mile, I never came again upon a flock of 
Crossbills when I had once put them up. I only once observed them on 
the ground; and this was in an open space in the forest abounding with 
ripe bilberries, upon which they probably had been feeding. 
The bill of the Crossbill has become specially adapted for extracting the 
seeds from the cones of the larch and various species of pine. The strongest- 
billed birds, to which the name of Parrot Crossbill has been applied, form 
a local race which live in the pine-forests and feed principally on the 
cones of the Scotch fir (Pinus sylvestris). The more slender-billed birds 
choose localities where spruce-fir and larch cones are obtainable ; they 
range further north durmg the breeding-season than their thicker-billed 
cousins—not because they are able to withstand a greater degree of cold 
but because the trees whose fruit form their favourite food are found 
further north. In the valley of the Yenesay the larch and spruce range to 
lat. 69°, whilst the Scotch fir only grows as far north as lat. 624°. The 
Crossbill breaks off the cone with his beak and flies with it to a thick bough. 
The cone is held firmly against the bough with one claw, exactly as a 
Raptorial bird holds its prey, and the cone is torn to pieces and the seed 
extracted with the bill, the outside covering or shell being removed and 
the kernel only eaten. The Crossbill also feeds on many other seeds, 
and is very fond of apples. Meves found them feeding in South Sweden 
on the caterpillar and chrysalis of a small green moth (Yortrix viridana) 
which is very destructive to oak trees, and it is said that the Crossbill 
generally feeds its young upon insects. 
The nest is generally placed in a pine tree of some kind, occasionally 
not more than five feet from the ground, but more often at a much greater 
elevation. ‘The favourite position seems to be almost at the top of the 
tree in the cup formed by the forking of the branches ; but it is not un- 
frequently built on a horizontal branch at some distance from the trunk. 
It is formed on the same model as the nest of the Bullfinch, an outside 
