72 



(EDICNEMTJS. 



Local distri- 

 bution. 



Ancient ( 



migrations. 



the Stone-Curlews are confined to the tropics. In Europe they are only found in the west 

 and south, where the winters are mild; in Africa they appear to be universally distri- 

 buted ; whilst in Asia they appear in every region, but are universally distributed over 

 none. In the Asiatic Palsearctic Region they are confined to the south-west ; in the 

 Oriental Region to the western half, and in the Australian Region to the eastern half. 



Of the nine species of Stone-Curlews five are almost as much steppe birds as the 

 Bustards ; whilst the other four frequent the mud-flats on the banks of rivers or the sea- 

 shore. They possess, however, one peculiarity in common : they are all very nocturnal in 

 their habits, feeding principally at night, and hiding as much as possible by day. This 

 fact suggests the theory that they were formerly residents on the Arctic tundras, where the 

 annual recurrence of three months' night compelled them to acquire nocturnal habits 

 during the period before they were finally driven south by the constantly increasing cold 

 of the post-pliocene glacial epoch. The absence of any species of the genus from the 

 steppes of Mongolia and China and the prairies of North America suggests the theory 

 that they were formerly more of coast-birds than they are now ; and that when they were 

 obliged to leave the Arctic tundras, instead of emigrating across country to the steppes of 

 Asia or the prairies of America, they joined the host of emigrants which followed the four 

 coast-lines leading southwards from the Polar Basin. It seems probable that their early 

 adoption of nocturnal habits prevented the necessity for the acquisition of migratory habits, 

 so that we may assume that they retired southwards as soon as the winters became too 

 cold to give them the necessary supply of food ; and having found suitable homes in the 

 south, they became permanent residents there, and did not return northwards when the 

 glacial epoch was over. 



CE. recurvirodris and ffi". magnirostris, and possibly OS. grallarius, are descendants of 

 the party which followed the Asiatic shores of the Pacific, and eventually found homes on 

 the rivers of India, the coasts of the islands of the Malay Archipelago, and the plains of 

 Eastern Australia — in which three locahties they were isolated from each other, and 

 eventually differentiated into the three species at present existing in these three districts. 

 These three species agree in being of large size and in possessing nearly black ear-coverts. 

 (E. superciliaris probably represents the party which followed the American shores of the 

 Pacific, and is now only known from the coast-regions of Peru. Its nearest ally {(E. hi- 

 striatus) must have followed the American shores of the Atlantic, and found a home in 

 Mexico and Tropical America, whence a post-glacial emigration led to the isolation of the 

 ancestors of ffi". dominicensis on the island of St. Domingo. The remaining four species 

 are the descendants of the party which followed the European shores of the Atlantic. 

 (E. crepitans was probably isolated on the shores of the Mediterranean, whence it spread in 

 post-glacial times to Western Asia and India ; having in the meantime despatched a party 

 of emigrants up the valley of the Nile, where they became diff'erentiated into (E. senega- 

 lensis, which gradually spread into West Africa. A second party followed the coast of 

 West Africa, and became differentiated there into (E. vermiculatus, which gradually spread 



