NORTHERN GRID 
PRELIMINARY REPORT AT-SEA' SURVEY NO. 33 
11-12 November 1966 
This brief report covers the observations conducted in the 
Northern Grid during the night of 11-12 November and throughput the 
day of 12 November 1966. The U.S.N.S. SHEARWATER (T-AG 177)» enroute 
to the south on SouthernIsland Cruise # 16, entered the Northern 
f A I 
Grid at 16° 03 N; 170 26 W at 2212 hours on 11'November and pro¬ 
ceeded southwest, departing the grid at 13° 55 N; 175° 10 W at 1759 
hours on 12 November (see Fig. 1)* The Smithsonian POBSP.observa¬ 
tion.party included Richard Crossin (Biologist in Charge), Dr. Robert 
Pyle, Kenneth Balcomb, Richard Chandler, Lawrence Huber, Richard 
Heiden, Chris Thompson, Johm Fitch and Robert Tuxsoh. 
Diurnal observations amounted to 11.8 hours covering 123 miles 
during which 163 birds of 6 species were observed and 4 specimens 
of 3 species were collected. Nocturnal observations amounted to 
8.3 hours covering 8l miles during which 25 birds of 6 species were 
observed. Only one specimen (a Leach's Storm Petrel which flew aboard 
ship) was- collected during nocturnal observations. 
Bird numbers were unusually low; November has shown the highest 
average density for the grid area over the past three years. An 
almost complete reversal of major species composition has occurred' 
since September 1966 when a similar short grid survey was made. At 
that time Wedge-tailed Shearwaters and Sooty Terns were the two dom¬ 
inant species, comprising 8l % of total birds. Only three Sooty/ 
Slender-billed Shearwaters were noted. During the present survey 
* 
no Wedge-tailed Shearwaters nor Sooty Terns were noted , and the 
dominant species was Sooty and/or Slender-billed Shearwaters. The 
second most numerous species was the Black-winged Petrel of which 
* Three Sooty Terns were noted during nocturnal observations. 
