IV FALCONIDAE 149 
advantage in Scotch deer-forests, where the noisy grouse disturb 
the stags, but being in peril of extermination on the moorlands ; 
yet it is questionable whether more good than harm is not done 
by the destruction of weakly game. The Osprey and Sea-Kagle 
eat little but fish, though they are not alone in that habit, while 
Rostrhamus lives almost entirely on fresh-water molluscs. Most 
members of the Family do not alight to capture their prey, but seize 
it with their sharp talons either sitting or on the wing, the chief 
exceptions being the carrion- and insect-eaters; it 1s often con- 
veyed to some favourite spot of ground or rock to devour, smaller 
objects being transported in the bill and the bigger torn to pieces 
and stripped before being swallowed. Large bones may be broken 
up, slender bones bolted entire; but hard substances are always 
ejected subsequently as pellets, after the manner of Owls (p. 401), 
the nature of the diet being readily detected from these castings. 
Exceptionally curious habits are credited to Gypaétus and Gypoic- 
tinia, as will be seen below. After a meal, quiescence is the rule, 
but none of the tribe gorge like Vultures. The predilections of 
species or even of individuals determine the situation of the nest, 
Eagles and other large forms preferring rocks in mountain-glens, 
lofty cliffs, or trees, for their bulky fabric of sticks, heather, and 
the like, which is lined with softer substances, and often bedded with 
foliage. The larger Falcons frequently select ledges on sea-girt or 
inland crags, and merely scrape a hole in the soil; but they, in 
common with the lesser Falcons, also utilize deserted habitations 
of Crows and so forth, or even lay their eggs on level ground or 
upon crumbling masonry; while the American “ Sparrow-Hawk ” 
(Tinnunculus sparverius) commonly appropriates old holes of 
Woodpeckers. Harriers, Rostrhamus, and other forms choose 
sites in reed-beds, gorse-coverts, fern, rough grass, or corn, and 
eschew hard materials; Hawks usually construct a flat platform 
of branches lined with thinner twigs. The eggs are generally 
bluish-, greenish-, or yellowish-white, with fine blotches, streaks, 
and spots of red, brown, or claret, chiefly towards the larger 
end; but in Falcons they are more or less covered with ruddy 
or orange markings, which often obliterate the ground-colour. Un- 
spotted specimens are not uncommon, and in the case of Harriers 
we have an instance of a plain bluish coloration, a few rusty 
stains being exceptionally visible. Alternative sites are frequently 
tenanted, or former nests repaired. Incubation is often of con- 
