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NORTH AMERICAN FAUNA. 



Dimensions. — Wing, 293; tail, 135 (length of middle pair of tail feath- 

 ers beyond lateral pair, 47); culmen, 42; tarsus, 50; middle toe, with 

 claw, 59. 



Rahitat, — The range of this species is now known to extend across 

 the middle North Pacific from Japan to the west coast of Mexico. 



Oceanodroma melania (Bonap.). Black Petrel. 



Common between Isabel and the Tres Marias. Black petrels were 

 by far the most numerous of the petrels seen, and outnumbered all the 

 others two to one. Three, and possibly four, other species were seen 

 on the way to and from the islands, but this was the only one secured. 

 They circled about in all directions, sometimes coming very near, but 

 nothing peculiar in their habits was observed. They were quick to 

 see little fragments of fat thrown overboard while we were skinning 

 other waterfowl, and when the morsels were small enough ate them 

 greedily. 



Phaethon aethereus Linn. Red-billed Tropic Bird. 



Tropic birds are readily distinguished on the wing by their graceful 

 ternlike flight and long filamentous tail feathers. Many of them breed 

 on Isabel Island and in suitable i)laces on rocky islets near San Bias 

 and about the Tres Marias. The last of April fresh eggs and nearly 

 grown young were found on Isabel, and by the last of May the young 

 on the Tres Marias had taken wing and few were to be seen, although 

 we were told by the tortoise shell hunters that many breed there earlier 

 in the season. 



Soon after landing on Isabel, a tropic bird was found sittiag on its sol- 

 itary egg at the end of a little hole in the rock close to the beach. The 

 hole was only about 15 or 18 inches across and about 3 feet deep, so that 

 tLere was no difficulty in taking the bird by hand after a little maneu- 

 vering to avoid its sharp beak. During a stay of about twenty-four 

 hours on this island at least 20 nests containing eggs or young were 

 examined. A single egg is laid directly on the rough rock or loose 

 dirt forming the floor of the nesting site, which is always located under 

 the shelter of over arching rock, but varies greatly in situation. The j 

 inner ends of holes in clift's facing the sea were favorite places, but as I 

 the number of such situations was limited, the birds were forced to I 

 utilize small caves and even rock shelters. In one locality five or six ' 

 nests were placed on loose earth at the bottom of rock shelters so situ- 

 ated that I could walk directly up to them and pick up the birds. 

 Whenever a nest was approached the parent screamed and fought 

 viciously, ruffled its feathers and looked very fierce, but made no attempt 

 to escape. They protested with beak and voice when pushed about, 

 but as soon as I went away a few yards they would shuffle back to 

 resume their former position over the egg. The young, even when 

 quite small, were equally fierce in resenting any intrusion. One nest 

 was found on the beach under the edge of some great rocks that had 

 fallen from the adjacent clift*. It was only 5 or 6 feet above high tide 



