Page:The Migration of Birds - Thomas A Coward - 1912.pdf/95

Rh plentiful and during the earlier part of the journey northwards only a few miles are covered per day; they travel with the slowly advancing vernal wave, but, as we shall show in the next chapter, many species actually outstrip it, and travel from warmer to colder climates.

By the kind permission of Mr Cooke I am able to reproduce three of his maps, illustrating the longest known distance travelled by any bird in a single flight, and the probable evolution of this extraordinary oversea voyage (21). This long journey, roughly 2500 miles at a ﬂight, is used in autumn by several species of American shore birds, and the particular species most easily recognised, is the American golden plover, Charadrius dominicus, which differs but little from our C. pluvialis. An important point to notice is that the route followed in the fall is not the one used by the bird in spring, an undoubted proof that all routes are not identical with the original line of dispersal of the species. Nor is the route directly from the north to the south, though there is plenty of evidence to show the fallacy of the notion that all birds move in this one direction.

The golden plover nests along the Arctic coasts of North America, from Alaska to Hudson Bay. So soon as the young are able to take care of themselves the birds migrate south-east to Labrador,