- 7 - 
birdSjwhere the "typical" forked tail and "typical" divided rump of Leach's 
were not evident because of molt or badly shot birds, the color of the oil 
(uropygial) gland was found to be a reliable character to separate these 
two species, ^each's have a creamy-white oil gland, that of the Galapagos 
is a dark grey. Any combination of the two or more races and the two species 
were encountered together in the field. 
Most specimens Vere collected over artificial oil slicks made with 
Wesson and/or cod liver oil. Throughout these oil slick operations I had 
the opportunity to test an old suspicion that storm petrels are able to 
detect an oil slick by smell. The evidence gathered during tie present 
; cruise strongly suggests this and a note concerning details of this phen¬ 
omenon is being prepared for publication. 
Identification of stomach remains in storm petrels is practically a 
lost cause because the majority of food is small, soft-bodied and quickly 
becomes unidentifiable through digestive action. In a few specimens of 
Leach's, however, the remains of squid v;ere plainly identifiable. One 
stomach contained the outer coat and "pen" of a squid which was estimated 
to be ca. six inches long in life. It is doubtful whether storm petrels 
are large or ferocious enough to catch such a live animal and I presume 
wounded animals are probably taken over feeding orgies of tuna. One Leach's 
had copepod remains in the stomach. 
'.'Jhite-throated Storm Petrel 3 
(Nesofregetta albigularis ) 
All three individuals were sighted south of the South Equatorial 
Current. 
Black Storm Petrel 11 
( Loomelania melania ) 
■ All sightings were made on 22 and 23 Febrviary of ship followers across 
the mouth of the Gulf of California, 
Fork-tailed Petrel 1 
i ( Oceanodroma furcate ) 
The single sighting vras noted with Black Storm Petrels following in 
1 the ship’s vake on 22 February at the mouth of the Gulf of California, * 
i Red-billed Tropicbird 14 
: ( Phaethon aethereus ) 
; . _ This is predominantly a coastal species. All sightings were along 
;■ ■ the Mexican mainland. One specimen was collected, 
• » 
j •. Red-tailed Tropicbird 21 
i ' ( Phaethon rubricauda ) 
! Scattered sightings were made from near 20 S to 15 N, but all occurred 
j along the western leg of the cruise. Five birds, mostly immatures, were 
j collected, 
I 
: White-tailed Tropicbird 2 
( Phaethon lepturus ) 
Two individuals circled the ship near 20^S on 13 February. These 
I probably are from one of the southern islands; Easter or Sala y Gomez. 
/ 
/ 
