38 CALIFORNIA ACADEMY OF SCIENCES. 



collect the gulls' eggs for the San Francisco market during 

 the first four weeks of their laying, after which they give 

 their whole attention to the murres. 



Usually three eggs constitute a setting, but from repeated 

 robbing often only two are laid. When more than one egg 

 is found in a nest by the eggers they are destroyed on sus- 

 picion of having been incubated. Gulls' eggs are collected in 

 the same way as the murres', but having thinner shells fewer 

 are carried for a load in the shirt or basket. 



A young gull from the islands, apparently but a few days 

 old, differs from the downy young described in "The Water 

 Birds of North America " (Vol. II, p. 230), in having the 

 abdomen and sides mottled, although the marks are not as 

 clearly defined as those of the back and head. 



The hundreds of gulls' eggs which I have seen vary con- 

 siderably in intensity of color. The average size of fifty 

 eggs, taken indiscriminately, was 70.2x49.4 mm. The 

 largest and smallest measurements found in this series 

 of fifty specimens were 76x51; 72x52; 72x48; 71x52; 71x46; 

 66x46; 65x48 millimeters. 



7. Larus californicus. 



California Gull. — More or less common during the fall. 



8. Larus heermanni. 



Heermann's Gull. — Occasionally seen by Mrs. Rugg. 



9. Diomedea albatrus. 



Short-tailed Albatross. — An adult male which I have 

 not seen, but which has been identified by Mr. Emerson, is 

 now in the possession of Mrs. Uugg. The bird followed a 

 ship to the island and was shot by one of the men on a tow 

 boat, March 20th, 1887. 



10. Oceanodroma homochroa. 



Ashy Petrel. — The last to arrive on the island is this 

 small petrel, which is also the rarest of the birds which 

 breed there. 



