HARRIER, or HEN-HARRIER, name given to certain birds of prey which were formerly very abundant in parts of the British Islands, from their habit of harrying poultry. The first of these names has now become used in a generic sense for all the species ranked under the genus Circus of Lacepede, and the second confined to the particular species which is the Falco cyaneus of Linnaeus and the Circus cyaneus of modern ornithologists.
One European species, C. aeruginosus, though called in books the marsh-harrier, is far more commonly known in England and Ireland as the moor-buzzard. But harriers are not, like buzzards, arboreal in their habits, and always affect open country, generally, though not invariably, preferring marshy or fenny districts, for snakes and frogs form a great part of their ordinary food. On the ground their carriage is utterly unlike that of a buzzard, and their long wings and legs render it easy to distinguish the two groups when taken in the hand. All the species also have a more or less well-developed ruff or frill of small thickset feathers surrounding the lower part of the head, nearly like that seen in owls, and accordingly many systematists consider that the genus Circus, though undoubtedly belonging to the Falconidae, connects that family with the Striges. No osteological affinity, however, can be established between the harriers and any section of the owls, and the superficial resemblance will have to be explained in some other way. Harriers are found almost all over the world, 1 and 1 The distribution of the different species is rather curious, while the range of some is exceedingly wide, one, C. maillardi, seems to be limited to the island of Reunion (Bourbon).
fifteen species are recognized by Bowdler Sharpe (Cat. Birds Brit. Museum, i. pp. 50-73). In most if not all the harriers the sexes differ greatly in colour, so much so that for a long while the males and females of one of the commonest and best known, the C. cyaneus above mentioned, were thought to be distinct .species, and were or still are called in various European languages by different names. The error was maintained with the greater persistency since the young males, far more abundant than the adults, wear much the same plumage as their mother, and it was not until after Montagu's observations were published at the Hen- Harrier (Male and Female).
beginning of the 1pth century that the " ringtail," as she was called (the Falco pygargus of Linnaeus), was generally admitted to be the female of the " hen-harrier." But this was not Montagu's only good service as regards this genus. He proved the hitherto unexpected existence of a second species, 2 subject to the same diversity of plumage. This was called by him the ash-coloured falcon, but it now generally bears his name, and is known as Montagu's harrier, C. cineraceus. In habits it is very similar to the hen-harrier, but it has longer wings, and its range is not so northerly, for while the hen-harrier extends to Lapland, Montagu's is but very rare in Scotland, though in the south of England it is the most common species. Harriers indeed in the British Islands are rapidly becoming things of the past. Their nests are easily found, and the birds when nesting are easily destroyed. In the south-east of Europe, reaching also to the Cape of Good Hope and to India, there is a fourth species, the C. swainsoni of some writers, the C. pallidus of others. In North America C. cyaneus is represented by a kindred form, C. hudsonius, usually regarded as a good species, the adult male of which is always to be recognized by its rufous markings beneath, in which character it rather resembles C. cineraceus, but it has not the long wings of that species. South America has in C. cinereus another representative form, while China, India and Australia possess more of this type. Thus there is a section in which the males have a strongly contrasted black -and grey plumage, and finally there is a group of larger forms allied to the European C. aeruginosus, wherein a grey dress is less often attained, of which the South African C. raniwrus and the New Zealand C. gouldi are examples. (A. N.)
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)