The birds of prey that haunt the moors are all more or less migratory in their habits, as might naturally be expected, because the species upon which they depend for food are non-resident too. The Red Grouse, it is true, is sedentary, but no raptorial bird frequents the moors that preys exclusively upon that species, and it chiefly suffers during the breeding season when the young chicks and poults are about. The Merlin is the most deadly enemy of these. It is a spring migrant to the moors, and is not known to breed with certainty south of Wales. It may just possibly do so on Exmoor, but certainly does not on Dartmoor; in fact, to Devonshire it must be regarded as a rare visitor in autumn and winter. We have always found the Merlin to be fairly common throughout the moors of North Derbyshire and South Yorkshire. It is ruthlessly persecuted by the gamekeeper, and its numbers consequently have declined almost to the vanishing point in not a few districts. We never saw much of the Merlin on the moors between Castleton and Sheffield before April. There are many favourite haunts on these moors in which the bird may be found breeding every summer; and curiously enough, although pair after pair may be destroyed, others come and settle in the district the following season. We are glad to be able to record that the bird has not been so severely hunted down in one or two places, and consequently its numbers seem to be on the increase. The spirited dash of this pretty little Falcon is not exceeded by that of the Peregrine itself. Times without number have we witnessed its fatal chase of the smaller birds of the moor—Twites, Ring-ouzels, Meadow Pipits, and less frequently of Plovers, Grouse, and occasionally Cuckoos. In the higher valley of the Rivelin, we once watched an exciting chase by this bird of a Common Sandpiper, which had been flushed from the heath-clad bank of one of the reservoirs at Hollow Meadows. Pursuer and pursued strove their utmost, the Sandpiper doubling, rising, and turning from side to side, and the relentless Merlin following closely every movement as though each bird were guided simultaneously by a common impulse. The chase was continued over the large reservoir, and we had a fine uninterrupted view of each bird’s powers of wing. The Sandpiper, after the water was crossed, gained a brief respite by hiding amongst the rushes on the opposite bank; but the Falcon, undeterred, hovered above the spot and once more flushed its quarry. The poor little Sandpiper wheeled rapidly round and then flew off across a rough bit of rock and heath-strewn ground, but its strength was exhausted; the Merlin’s superior powers of flight and endurance asserted themselves, and the Sandpiper, with a piteous weet weet of terror, was struck down. But the various birds of the moorlands are by no means the Merlin’s only food. Like most, if not all the smaller Falcons, it subsists largely on certain insects. Whether the bird’s good offices in this direction counterbalance its tax upon young Grouse we need not stay here to enquire. Perhaps in this case they do not, for the insects caught can do little or no damage in such localities; but on the other hand, we must remember that the Falcon assists in keeping up the Grouse to a strong and vigorous standard by killing off—if amongst others—a certain percentage of weakly and unfit birds. There is some evidence to show that Grouse disease appears in regular cycles on most moors—say every seven years—and competent observers have attributed it to old birds spreading the contagion. Now, had the larger Raptores not been so ruthlessly exterminated in these localities, surely it is only reasonable to suppose that they would have thinned out many of these birds, not perhaps preventing an epidemic, but thus assisting in rendering it of a milder character than otherwise prevails. Depend upon it, man seldom or never meddles with the delicately-adjusted balance of nature without unfortunate results in some direction. But to return to the Merlin and its economy. Like the Sparrow-hawk and many other raptorial birds, this pretty species selects some spot or spots in its haunts to which it conveys its captures to devour them in peace. The nest is almost invariably made at no great distance from these “dining-tables” or “larders”, where the bare and often rock-strewn ground is sprinkled with feathers, bones, pellets, wing-cases and wings of insects, the remains of the Merlin’s food. These haunts, as previously remarked, are tenanted yearly with wonderful regularity, and the nest each season is made in much the same locality as in previous years. This nest is of the simplest, and always, so far as we know, upon the ground. “Nests” have been recorded in Scotland in the old nest of some other bird in a tree;[2] whilst in some foreign countries a ledge of a cliff is said to be selected. Our experience is that it is invariably upon the ground, and generally on a rather bare spot amongst the heather or ling, often on an eminence of some kind. Here in a slight hollow, with no lining as likely as not, the four or five pretty red eggs of the Merlin are laid. They are absolutely indistinguishable from those of the much commoner Kestrel, but their terrestrial resting-place should prevent the novice confusing them in situ. In autumn the Merlins quit the moors. It is difficult to say how far these birds indigenous to our own moorlands migrate; there is evidence to suggest that the movement is limited to a trip to the lowlands, extending even to the coast. On the other hand, the bird is certainly a species with a strongly marked and regular passage in most parts of its extra British range. A word as to the plumage of this interesting Falcon. The cock bird, with his slate-gray upper parts, rufous nape, more or less distinctly barred tail, dark wings, and rufous under parts streaked with dark brown, is possibly familiar to most readers. The hen bird, so far as we can determine, is not only slightly bigger than her mate, but much less handsome in colour. She is dark rufous-brown on the upper parts, each feather with a paler margin, the buff