IV FALCONIDAE 



149 



advantage in Scotch deer-forests, where the noisy grouse disturl) 

 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-Eagle 

 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 is 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 Gypaetus 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, Rostrharmis, 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- 



