These birds inhabit the northern portions of the Eastern Hemisphere, and from thence wander forth to visit Central Asia, Egypt, and Nubia, only occasionally venturing as far as Southern Asia or Central Africa. The autumn migration is undertaken in large parties, which fly in a direct line towards their destination, whilst in the spring, on the contrary, the males return first, and steer their aërial course as far as possible in the immediate vicinity of the banks of rivers or any large bodies of water, as in such localities they find an abundant supply of the worms, beetles, and similar fare that afford them their principal means of subsistence. The disposition of the Blue-throats in every way corresponds with their attractive appearance, and their intelligence is by no means inferior to that of the Nightingale. All their movements are characterised by a liveliness that seems to indicate a thorough enjoyment of existence; and their demeanour, as they hop quickly over the ground, with body erect and tail outstretched, evidently denotes a most satisfactory consciousness of their own personal charms. When climbing among, or perching on the branches of a tree or bush, they show to less advantage; and their flight, through rapid, cannot be maintained for any great distance. The sung of the various species differs considerably in quality; that of the Swedish Blue-throat is, perhaps, the least pleasing to the ear, owing to the fact that the various strophes that compose it are each in turn repeated with a frequency that soon becomes wearisome to the hearer, after he has ceased to amuse himself with the strange droning under-tone or accompaniment kept up by the bird during the whole song, which produces the effect of two distinct voices. Amongst the Lapps this species is known as the "Hundred-tongued Warbler," from the great faculty it has for imitating, not only the notes of birds, but a great variety of sounds. Like the Hedge Warblers generally, it is most unwearied in these vocal exertions, which are often continued even whilst the little songster is running upon the ground. The nests built by the Blue-throats are often concealed in bushes, or among the roots of trees, with so much care as to render their discovery a work of difficulty. Holes in the banks of rivers or brooks are also sometimes selected for the reception of the nest; that side of the water, according to Hinz, always being preferred which is most exposed to the rays of the morning or noon-day sun. The nest itself is large, open at the top, and formed of twigs and stalks of plants, lined with delicate blades of grass, and in northern latitudes with wool or hair. The eggs, which are laid in the middle of May, are from six to seven in number, and have delicate light blueish green shells, marked with reddish brown spots, and clouded with brown at the broad end. Both parents assist in the work of incubation, which lasts for about a fortnight. The young are reared upon worms and beetles.