n/ 



V 



^16 Anthony, Avifauna of the Revillagigedo Islands. Loct 



reasonabl}' sure that thej represented an immature bird of tiie present 

 species. 



2. Sterna fuliginosa. Sooty Tern. — A large colony was found nest- 

 ing on a rock a mile off the southwest point of the island. On May 12, 

 we found most of the eggs hatched and many young were half-fledged. 

 The eggs were single and laid on the bare rock. From the series of skins 

 taken it would seem that ' var. crwirt//* Baird ' would eventually have to 

 be recognized. The material is insuificient, however, to warrant a definite 

 conclusion. 



3. Anous stolidus ridgwayi. Ridgway's Noddy. — A large colony were 

 nesting with the preceding species. Most of the eggs were fresh on May 

 12. They were laid on the bare rock with no attempt at nest building. 



Terns were not seen about any of the other islands of the group. 



4. Puflfinus cuneatus. 



5. Puffinus auricularis. — Both these Shearwaters were seen at sea about 

 the island. No evidence of their nesting was noted, however. 



6. Oceanodroma kaedingi. Kaeding's Petrel. — Common at sea near 

 the island. Apparently migrating. 



7. Phaethon sethereus. Red-billed Tropic Bird. — Common at sea 

 and about all outlying rocks. 



8. Sula cyanops. 



9. Sula brewsteri. 



10. Sula websteri. — Boobies were much less abundant about Socorro 

 than at San Benedicte. Quite a colony were gathered about the cliffs on 

 the southwest end of the island, but elsewhere they were only seen in 

 small numbers, as they followed the small fish on which they fed. 



11. Fregata aquila. Man-o'-War Bird. — Qiiite common with the 

 Boobies, following them about the island and robbing them on all 

 occasions. 



12. Ardea herodias. Great Blue Heron. — Not uncommon. Several 

 were seen at each of our stations. 



13. Nycticorax violaceus. Yellow-crowned Night Heron. — Q^iite 

 common all over the island. Fully fledged young were shot May I4_ 

 They seemed to be feeding extensively on the land crabs, the shattered 

 remains of which were often seen together with the tracks of this species. 



14. Heteractitis incanus. Wandering Tatler. — Occasionally seen 

 all along the shore. 



15. Actitis macularia. Spotted Sandpiper. — A single bird was seen 

 on the north side of the island May 14. 



16. Zenaidura graysoni. Grayson's Dove. — This species did not 

 seem to be at all common, but was perhaps more abundant- in the higher 

 parts of the island, which were very difficult of access. 



17. Columbigallina passerina socorroensis. Socorro Ground 

 Dove. — Rather common everywhere on the island. 



18. Buteo socorroensis. Socorro Red-tail. — Not at all common and 

 very wild. 



