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STORM PETRELS (HYDROBATIDAE) 



This group includes the smallest seabird. Some are as small as sparrows 

 and others no larger than robins. Except for one species, all are dark 

 brown or gray with or without white rump feathers. If only a wing is 

 found, identification will be difficult and should be confirmed by some- 

 one very familiar with these birds. For that matter, even the identifi- 

 cation of entire specimens would best be confirmed by an experienced person, 



FORK TAILED STORM-PETREL (Oceanodroma furcata; choice 2, pg. 27). 

 Because these birds are pearl gray they cannot be confused with other 

 species of storm-petrels occurring off the coast. North of central 

 California, and into the Bering Sea, they should be expected at any time 

 of year in ice-free areas. South of this region they are more likely to 

 occur during winter but only on rare occasions. 



LEACH'S STORM PETREL (Oceanodroma leucorhoa; choice 7 and 8', pg.28 ). 

 This species' size and the dark central feathers in its otherwise white 

 rump should distinguish it from other white-rumped species. Unlike other 

 storm-petrels, from central California south, the rump color of Leach's 

 Storm-Petrels varies tremendously from totally white to totally dark. 

 The greatest difficulty will be in distinguishing dark-rumped Leach's 

 from other dark-rumped species. Careful consideration of characters 

 mentioned in the key should suffice in most cases. 



North of central California this and the previous species are the 

 only storm-petrels that one should expect to encounter. Leach's Storm- 

 Petrels rarely occur in the Bering Sea even though they breed on many of 

 the Aleutian Islands. From central California north one should find them 

 only during the spring, summer, and early fall. To the south, as far as 

 Baja California, they could be encountered year round. 



BLACK STORM PETREL (Ooeanofooma melania; choice 3, pg,27 ) is the 

 largest of the all dark storm-petrels off this coast and size alone should 

 distinguish it from any other species. It occurs in southern and Baja 

 California waters mainly from spring to fall although winter occurrences 

 would not be unusual. North to central California they occur quite 

 regularly during late summer and fall. From there north, specimens 

 should be saved for verification. 



ASHY STORM PETREL (Oceanodroma homoohroa; choice 9', pg.28 ) is the 

 all dark species most similar to the all dark Leach's Storm-Petrel . The 

 fact that it is ashy gray (especially at tips of tertials and secondary 

 coverts), fading in the late summer to brown, should separate it from 

 Leach's which is dark chocolate brown and fades to lighter brown. The 

 underwing coverts are the best to check for these color differences, 

 since fading does not occur very much there. The buffy bar running 

 through the upper wing coverts is much more prominent in Leach's Storm- 

 Petrel. Experience in distinguishing these two birds in the hand helps 

 a great deal since it is not necessarily an easy undertaking. 



