White-capped Noddy 
(Anous mlnutus) 
The single sighting of this species on February l6 is probably 
from Clipperton Island* 
Sooty Tern 
( Sterna fuscata ) 
The most abundant species of the trip and the dominant species of 
areas "C”, "F”, and ’’F”. The distribution was not as uniform as 
Leach Storm Petrel, but Sooty Terns were present in large numbers 
in select areas* 
Several populations representing different island origins were 
encountered. South of the equator Sooty Terns were probably from the 
Marquesas Islands* The iminature found in this area was in fresh 
plumage indicating a fall nesting population characteristic of the 
^'^^arquesas. 
Flocks feeding adjacent to Clipperton Island contained dark 
immatures. These birds are most likely of Clipperton origin 
and indicate a prolonged nesting season in Clipperton. Immature Sooty 
Terns recorded around th® Revilla-Gigedos and to the east were 
molting from immatures to sub-adult plumage. These individuals appear 
light brown and are probably about 10 months old* 
An interesting ethological note is the lack of nocturnal sighting 
along the shipping lanes. 
White Tern 
( Gygis alba ) 
Fairy Terns were observed casually in the Southern hemisphere. 
Individual sightings were of birds feeding alone, or in association 
with Sooty Tern flocks. Those birds are probably from the Marquesas 
Islands. 
Xantus Murrelet 
( Endomych ura hypoleuca . x 
Observed adjacent to Baja California and identified as to race 
by their white underwing* x 
