_Aesalon regulus_, the Merlin, called the Stone-Falcon from its habit of perching on rocks, is a lively and interesting little species, daring yet confiding, which preys chiefly upon small birds, and flies less swiftly than the Hobby, though both are used for Lark-hawking. The shrill note is chiefly heard at the breeding-quarters, which in Britain are generally on steep hill-slopes, especially where stony outcrops break the heather or grass; from four to six eggs–duller and less blotched than those of the Kestrel, being deposited in a hole scraped in the bare ground. Abroad–and exceptionally in Scotland–old nests in trees or rocky ledges are utilized, and the bird is perhaps occasionally its own architect. Fairly common north of Derbyshire its summer range extends over the moorlands from Shetland to Devonshire, and includes Ireland, while it visits the sea-coast in autumn. It occurs accidentally in Greenland, and reaches thence to the Pyrenees and the Alps, being found across Northern and Central Europe and Asia, and migrating to North Africa, North India, and South China. The male is slaty-blue with rusty nape and under surface, and is streaked with dusky throughout; the throat is white, as is the tip of the tail, which, besides six imperfect bars, shows a broad sub-terminal black band. The dark brown female has the lower parts white, the rectrices exhibiting eight light {178}bars. In the very similar _Ae. columbarius_, the "Pigeon Hawk" of North America, extending to Venezuela and Ecuador, the tail-bars in the respective sexes are four and six. This species and the following usually build in trees, using twigs, roots, grass, and moss for their nests. _Ae._ (_Chicquera_) _typus_, the Indian "Turumti," is a larger bird, both male and female being grey above and white below, with red head and dark barring nearly throughout, while Ethiopian _Ae._ (_C._) _ruficollis_ is slightly less striped.