March 1964 



April 1964 October 1964 



November 1964 



May 1964 



lune 1964 December 1964 



lanuary 1965 



luly 1964 September 1964 



Q> Winterers ^> Migrants ^> Unidentitietl Q>Breeders 



February 1965 



Q> Winterers ^> Migrants 



March 1965 



Unidentified Q> Breeders 



Figure 26a. — Relative composition of avifauna by 

 species group, March-September 1964. Numbers 

 in parentheses in each sector indicate the 

 percentages of total birds in each category. 



Figure 26b. — Relative composition of avifauna 

 by species group, October 1964 to March 1965. 

 Numbers in parentheses in each sector indi- 

 cate percentages of total birds in each 

 category. 



study area on its northward migration to the 

 North Pacific; Gray-backed Tern, Blue-gray 

 Noddy, and Rock Dove originate on the main 

 Hawaiian islands. 



If we subdivide the species occurring in the 

 study area somewhat more broadly into breed- 

 ing birds (of the central Pacific, including 

 Hawaiian, Line, and Phoenix Islands), wintering 

 birds from the North or South Pacific, and 

 direct migrants through the study area from the 

 North or South Pacific, we can show the rela- 

 tive abundance of each of these groups, and, 

 thus, the patterns of utilization of the study 

 area as they relate to the location of breeding 

 areas and breeding phenology (figs. 26a-c). 



Generally, the species in the area during 

 their breeding season have breeding grounds 

 within 1,000 miles of the study area; those that 

 occur during their nonbreeding season come 

 from more than 1,000 miles away. 



Resident in Breeding Season. 



Black-footed Albatross 

 Laysan Albatross 

 Dark-rumped Petrel 

 Bulwer's Petrel 

 Wedge-tailed Shearwater 

 Christmas Shearwater 

 Newell's Shearwater 

 White-tailed Tropicbird 



65 



