Page:The Migration of Birds - Thomas A Coward - 1912.pdf/147

Rh what is the effect on a flying bird which suddenly enters one of these pockets?

The lesser black-backed gull also Crosses England in large numbers; its movements are more noticeable than those of the herring gull, common gull, or even of the inland nesting and inland feeding black-headed gull.

Recent investigation has added the yellow-browed warbler, the blue-throat, and many other "rare," or "casual" passerine birds to the list of regular British birds of passage; evident1y they have been overlooked before, Even the crossbill, so long classed as a spasmodic invader, is now seen to be a regular bird of passage to Britain, though in varying numbers, and quite independently of the sub-specific form which is always with us.

The wanderings to our islands of southern petrels and other oceanic birds has occasioned much surprise. Take two examples of the genus Oestrelata, one O. brevipes taken at Earth in 1889, and O. neglecta in Cheshire in 1908, the known breeding range of both being in the western Pacific; pelagic wanderings might lead a bird anywhere, but it is conceivable that investigation may show that the breeding area is wider than is supposed and that these species have stations even in the South Atlantic.