56 BULLETIN 121, UNITED STATES NATIONAL MUSEUM. 



In their vain endeavor to escape from the brilliant light. No nest of any 

 description was attempted. by the birds in these caves. 



Another colony had chosen a very different situation on the, plain east of 

 Mount Amarilla, about a quarter of a mile from the sea. Here the birds were 

 nesting in burrows in the earth, which was so hard that It absolutely resisted 

 our attempts to dig out the occupants with a sharp-pointed spade. I imagine 

 the shearwaters had excavated these burrows themselves, as there are no 

 rabbits on Graciosa whose holes they could make use of. I only found one 

 other small colony on Graciosa, where the birds nested in burrows which like- 

 wise were too difficult to excavate. 



Not content with nesting round the coasts, these birds had resorted in num- 

 bers to two of the volcanoes. A few nests were found amongst the lumps 

 of loose lava on the summit of Montana Bermeja (550 feet), but a consider- 

 ably larger colony was discovered on the eastern slopes of the big central vol- 

 cano (Montana de las Agujas). Here, at an altitude of 300 to 600 feet the 

 face of the crater was honeycombed with caves, In almost all of which birds 

 were nesting. As this was the most interesting of all the various sites chosen, 

 I will give a short description of my visit on June the 1st. Two fisher lads 

 acted as guides, and after a weary climb up 600 feet of loose crumbling lava, 

 we gained the entrance to the lairgest cave, which measured 6 by 3 feet. At 

 one end of this outer cave a narrow tunnel ran into the heart of the mountain, 

 through which, by lying full length, It was just possible to squeeze; after 

 being pulled in front and pushed behind for some fifteen yards, I at last found 

 myself in another small cave, with yet another tunnel leading out of it at 

 right angles to the last. This second tunnel was a little wider, but twisted 

 and turned In the most bewildering manner, gradually opening out into a 

 good-sized cavern which must have been quite twenty yards from the entrance. 

 All the large holes and crevices in the walls of this cave had been utilized by 

 the shearwaters. A very large number must resort to this particular spot. 

 At this distance from the fresh air an indescribable smell of petrel greeted 

 our nostrils. The fioors of both caves and passages, which were composed of 

 crushed lava, were thickly strewn with the feathers of the birds, and I was 

 unlucky in finding all the occupants out at sea. They had not yet commenced 

 to lay, at any rate in this cave, but we had. obtained a fair number of eggs 

 from other parts of the island. 



Eggs.— The eggs of the Cory shearwater vary considerably in size 

 and shape but are indistinguishable from those of the closely related 

 Mediterranean birds. The shape varies from ovate or even pointed 

 ovate to elliptical ovate. The color is pure white. The shell is 

 smooth, though slightly pitted, and without luster. 



The measurements of 70 eggs, from the Canaries and the Desertas, 

 collected for me by Rev. F C. E. Jourdain, average 75.30 by 50.3 

 millimeters; the eggs showing the four extremes measure 83 by 48 

 79 by 55, 66 by 47, and 73.5 by 45 millimeters 



Behavior.— Mt. Ogilvie-Grant (1896) writes of the habits of this 

 species on the Salvages : 



Our arrival on Great Salvage apparently caused great excitement among 

 the bird inhabitants, our tent being a special object of wonder, the pardelas or 

 Mediterranean shearwaters, being especially bold and noisy in their greetlnK 

 The high volcanic rocks surrounding the south bay are full of miniature caves' 



