TO Grinnki.1^ AissD Daggktt, Birds o/ Co fonados Islafids. Lun 



Tugged nature of this island makes it the favored one of the 

 group for the larger seabirds, thousands of which annually nest 

 here. We spent the forenoon in climbing about the rookeries 

 and examining the nesting sites, most of which were by this 

 time abandoned. Our visit was much too late, for most of the 

 young had left. This locality would furnish many an interesting 

 •object for the bird photographer during April and May. At noon 

 we returned to the cove at North Island, where the launch met us, 

 and in the evening of the same day we were back at San Diego 

 with many hours of tedious bird-skinning to look forward to. 



The following is a more detailed account of all the birds we 

 found at Los Coronados Islands. 



Notes on Species. 



1. Ptychoramphus aleuticus. Cassin Auklet. — Large plats of soft 

 ground near the top of North Island were percolated with burrows, larger 

 than the normal ones of petrels. Many were dug into but proved empty 

 save for fragments of white egg-shells and in one case a dead young 

 Cassin Auklet. Large numbers of this species evidently breed here 

 earlier in the year. 



2. Larus occidentalis. Western Gull. — This species was numerous 

 about all the islands. At North Island clouds of fully fledged young and 

 adults kept circling about overhead during our stay there. A few young 

 still unable to flv were met with toward the south end of this island. 

 These were possessed of remarkable agility in scrambling among the 

 rocks into places of concealment. 



3. Larus heermanni. Heermann Gull. — Many gulls of this species 

 were congregated over the kelp beds among the islands. All seen were 

 in the dark-headed, immature plumage, not a single adult being observed. 

 These were all probably northward migrants from some winter breeding 

 ground far to the southward. 



4. Oceanodroma melania. Black Petrel. — This species was breeding 

 sparingly on Middle and North Islands in company with the Socorro 

 Petrel. We obtained but four specimens, each with an egg. The four 

 eggs were white, though more or less nest-soiled, and unspotted. They 

 measured, in inches, 1.50 X 1.04, 1.44 X 1.03, 1.37 X 1.08, and 1.52 X 1.02, 

 or, in millimeters, 38 X 26.7, 36.7 X 26.4, 35 X 27.5, and 38.6 X 26. Three 

 of these eggs were on the point of hatching, the other being infertile. 

 The nesting burrows of the Black Petrel seemed to us indistinguishable 

 from those of the Socorro Petrel described beyond. Bonaparte's Procel- 

 laria melania (Compte Rendu, XXXVIII, April 1854, p. 662) was described 



