123 



Ashy Storm Petrels occur year round from northern Baja California 

 to central California, and in the fall sometimes occur in northern 

 California waters. 



GALAPAGOS STORM PETREL (Oceanodroma tethys; choice 6, pg. 27), is a 

 very small white-rumped species that is most easily confused with small, 

 white-rumped Leach's Storm-Petrels from Guadalupe Island, off the central 

 Baja California coast. The size of the rump patch relative to the tail 

 length, as described in the keys, should be checked carefully. When 

 checking tail length be sure to note whether feathers are still growing. 



On only a few occasions has this species been reported in waters off 

 this coast and never north of central California. All specimens should 

 definitely be saved for verification. 



HARCOURT'S STORM PETREL (Oceanodroma castro; choice 7', pg. 28 ) has 

 been reported in this region only at sea off southern Baja California. 

 The white bases of tail feathers should separate any specimen from other 

 white-rumped species. 



LEAST STORM PETREL (Halocyptena miorosoma; choice 9, pg. 28 ). The 

 extremely small size should separate any specimen of this species from 

 any of the other all dark storm-petrels. The square or even rounded 

 tail is also distinctive. 



Least Storm Petrels occur quite commonly from Baja California north 

 to southern California. They have been reported as far north as northern 

 California. Off Baja they occur during the spring to fall period, but 

 north of there, occurrence is pretty much restricted to the fall. 



WILSON'S STORM PETREL (Ooeanites ooeanious; choice 5, pg. 27). The 

 very long tarsi, yellow-webbed large feet, and white lower belly (as well 

 as rump) are characteristics of this species that collectively should set 

 it apart from any others. This visitor from the Southern Hemisphere 

 occurs regularly but in extremely small numbers in west coast waters, 

 mainly during the fall. It has been reported at least as far north as 

 Washington. Any specimens should be saved for verification. 



TROPICBIRDS (PHAETHONTIDAE) 



RED-BILLED TROPICBIRD (Phaethon aethereus; choice 13, pg.21 ). About 

 the size of a Western Gull, these birds are largely white all over except 

 for fine, black barring on upper parts. Primary wing coverts are black, 

 as is the upper surface of the outer 5 primaries. The bill is very heavy 

 but similar in shape to that of a Caspian Tern (compare Plates 4-2 and 

 29-1). In adults the bill is scarlet but in juveniles it is yellow. 

 The feet are black. 



