DERIVATION OF THE FLORA AND FAUNA 293 



Asio flavDiieus Pontoppidan (A. f". suinda Vieillot). Masatierra. The typical spe- 

 cies almost cosmopolitan; suijida ran<j;es over South America from X'cnczuela to 

 Fuegia. 



Ceroids sparrcriiis (L.) ssj). fcDuvidoisis Cha[Mii. (Falco s. f.). Masatierra, 

 endemic, the species distributed from North America and the West Indies to northern 

 South America, another ssp. in Chile. A genus of 28 species and very wide 

 distribution, but not recorded for Oceania. 



Buteo eryt/irouofus King ssp. exsul Salvin (B. polyosoma e.). Endemic on Masa- 

 fuera, an accidental visitor to Masatierra; typical erytJironoius ranges from Peru 

 to the Magellan Straits and Falkland. On Masafuera the principal food of the 

 buzzard are rats, mice and \-oung goats' kids, all introduced by man, but it has 

 been observed attacking petrels and thrushes. A widespread genus of 33 species 

 (Amer., Euras., Austral., Ocean.). 



Breeding sea-birds. 



Fregetta grallaria Vieillot. Masatierra and Santa Clara and also Desventu- 

 radas (San Ambrosio); coasts and islands of the Indian and Pacific Oceans. 

 4 species, subtropical-tropical seas. 



Puffiniis crcatopus Coues. Masatierra and Santa Clara; California-S. Chile, 

 where it breeds on Mocha I. and islands in the vicinity of Chiloe. Migrates during 

 the winter to Peru and along the coast north to Alaska, returning south in No- 

 vember. The genus (28 sp.) is world-wide. 



Ptcrodrouia 7icglecta Schleg. Masatierra and Santa Clara; also on San Am- 

 brosio and further reported from Lord Howe and Kermadec Is. Strolls north during 

 the winter. A genus of about 30 species spread over the south hemisphere and 

 extending north to the north Atlantic and to Japan. 



Ptcrodrouia externa Salvin (P. e. externa). Endemic on Masafuera, migrates 

 north as far as Costa Rica. Another race breeds on Tristan da Cunha, a third 

 on Kermadec Is. 



Pterodroiiia cooki Gray ssp. defilippiana Gigl. et Salvin. Endemic to Santa 

 Clara, Masatierra and Desventuradas. Typical cooki on New Zealand, /'. cooki orien- 

 talis Murphy on the coast of Peru and Chile, but breeding places unknown; 

 defilippiana is said to extend its flights to Peru. 



Ptcrodrouia cooki ssp. niasafuerae Lonnb. (P. leucoptera Masafuerae). Masafuera, 

 endemic. At first LoNXBERG felt inclined to identify the bird with P. c. leucoptera 

 "in spite of the zoogeographical difficulties for such a theory" (p. 15); LoNNBERG's 

 opinion is strengthened by the fact that, whereas defilippiana and leucoptera are 

 surface-breeding like neglecta, externa and masafuerae are burrowing. 



Two aliens are naturalized in the islands, a melanistic form of Coluuiba livia 

 Briss. in the i8th century and now conunon, zx\^ Lop hortyx calif ornicus "^XxdiW Q.X 

 Nodd, introduced 19 12 or 191 3. Several landbirds have been observed as acci- 

 dental visitors, Crymophilus fulicarius and Buteo obsoletus migrants from the north 

 and Belo7iopterus chilcjisis, Cathartes sp., CygJius nielajiocoryphus, Haematopus ater 

 and Circus inaculosus from the opposite coast. Petrels, albatrosses, Cape pigeons 



