NORTHERN PELAGIC: 895 miles and 86.2 hours of observations were completed 
in this area. Twenty-one species were recorded, of which Juan Fernandez 
petrels were the most abundant. Average density was O .56 BSM, but most of 
these birds were found within the warmer waters in the southeastern part. 
Only Black-winged Petrel, Soccorro Petrel, and Red-tailed Tropicbird were 
more common in the western part (ill 0 -119°W). TABLE 3 shows the species 
present and their comparative abundance. 
TABLE 3 
DISTRIBUTION AND ABUNDANCE OF BIRDS IN NORTHERN PELAGIC WATERS 
Species 
No. Birds Birds/Hour Area of greatest Abundance 
Wedge-tailed Shearwater 80 
Sooty Shearwater 4 
Manx Shearwater 21 
Herald Petrel • 1? 
Kermadec Petrel 3 
Phoenix/Tahiti Petrel 1 
Murphy Petrel 2 
Dark-rumped Petrel 1? 
Juan Fernandez Petrel 3^9 
Black-winged Petrel 7 
Leach Petrel 6l 
Soccorro Petrel 7 
Least Petrel 5 
Sooty Petrel 5 
Red-tailed Tropicbird 6 
Red-billed Tropicbird 6 
Blue-faced Booby 10 
Brown Booby 8 
Red-footed Booby 5 
Pomarine Jaeger 5 
Sooty Tern 1 
0.93 
13-15° 
N 
- 
101-103' 
0.05 
- 
0.24 
13-15° 
N 
- 
098-103 
0.01 
- 
0.03 
• 
- 
0.01 
- 
0.02 
- 
0.01 
- 
4.05 
13-15° 
N 
- 
101-103 
0.08 
12° 
N 
- 
118° W 
0.71 
Random 
? 
0.08 
250 
N 
- 
118° w 
0.06 
- 
0.06 ’ 
13° 
N 
- 
097° w 
0.07 
12° 
N 
“ 
118° w 
0.07 
13° 
X 
- 
097° W 
0.12 
13° 
N 
- 
097° w 
0.09 
15° 
N 
- 
101° w 
0.06 
15° 
N 
- 
101° w 
0.06 
13#17° 
N 
- 
101-106 
0.01 
- 
W 
W 
W 
COUNTERCURRENT: 899 miles and 85.7 hours of observations were completed 
in this area. Twenty-five plus species were recorded with Juan Fernandez 
Petrels outnumbering all others. Average density was 1.71 BSM. In the 
western section birds were concentrated at the southern boundary, whereas 
in the eastern section they were concentrated at the northern boundary. 
This, plus the fact that some species (eg. Manx Shearwaters, Boobies, 
Frigatebirds) were found only in the eastern section, and that the Counter 
current was not detectable in the eastern section, shows the effect 
that water masses may have on the distribution of pelagic birds. TABLE 
4 shows the distribution and comparative abundance of birds within this 
area. 
