Nofthern Sooty Tern Population 

 Souttiern Sooty Tetn Population 



o 2,000- 



500 - 



Figure 23. — Monthly abundance of northern and southern populations of Sooty Terns. 



Distribution : Although the distribution in any 

 given month appeared to be random, a tendency 

 to favor certain parts of the area and to avoid 

 others became apparent when White Tern sight- 

 ings on all 15 cruises were plotted together 

 (fig. 24). Density centers were noted between 

 50 and 100 miles east and southwest of Hawaii. 

 The northeastern portion of the study area was 

 avt)ided rather consistently. 



Rock Dove 



Columba livia Gmelin 



Status : Accidental. 



On May 4, 1964 a lone Rock Dove circled the 

 ship twice 10 miles north of Oahu, where the 

 species is abundant. 



Monthly Summary 



March 1964 



Sooty Shearwaters, migrating north for the 

 summer, were the most numerous species in 

 March. Sooty Terns were the second most 



abundant, concentrating north of Oahu where 

 their breeding season was getting underway. 

 These two species accounted for 83.1 percent 

 of all birds seen. Wedge-tailed Shearwaters 

 had not yet entered the study area in large 

 numbers. Black-footed Albatrosses were still 

 present in fair numbers near their breeding 

 islands in the leeward Hawaiian chain. Num- 

 bers of Leach's Storm Petrels were still at 

 their winter level before the spring buildup. 



April 1964 



Total density remained relatively unchanged. 

 Migration of Sooty Shearwaters had slowed down 

 considerably although fair numbers were still 

 seen each day. Sooty Terns predominated, 

 especially within 100 miles of their breeding 

 islets off Oahu. Wedge-tailed Shearwaters in- 

 creased as their breeding season began in the 

 Hawaiian Islands. Leach's Storm Petrels at- 

 tained peak numbers this month as they began 

 their northward movement to their breeding 

 grounds in the Aleutians. Albatrosses declined, 

 and their range retracted northward. 



58 



