PH. NIQRIPENNIS 



APRIL 1964 



MAY 1964. 



♦«l^ 



Figure 7a. — Distribution of Black-winged Petrel, April-July 1964. 



Black-winged Petrel 



Pterodroma hypoleuca nigripennis (Rothschild) 



Status : Abundant visitor during nonbreeding 

 season, May-November; uncommon or rare 

 December-April. 



Months 



January 



February 



March 



April 



May 



June 



July 



August 



September 



October 



November 



December 



Year 



1964 



4 



2 



69 



176 

 116 



92 



1,033 



268 



19 



1965 



4 

 

 

 1 



147 

 130 



Black-winged Petrel was first observed in 

 the study area on March 17, 1964. Only an 

 occasional bird was seen until May when num- 

 bers began to increase. Numbers were fairly 

 stable from May through September but rose 

 sharply in October. A decrease in November 

 to a level somewhat higher than the May- 

 September level was followed by a sharp re- 

 duction in December and January. No birds 

 were seen in the 1965 season until April 24. 



This bird attained its greatest density in 

 October shortly before, or concurrent with, its 

 reappearance on its breeding grounds on the 

 Kermadec Islands. By the time eggs were laid 

 (December) numbers in the study area were 

 greatly reduced. No birds were seen in the 

 study area from the time of hatching to fledging. 



Distribution : In May birds appeared in the 

 southeast third of the study area (figs. 7a, 7b). 



16 



