no. 3605 SEABIRDS — GILL 5 



sions reached 100-200. 2 In the intervening seas an average of one bird 

 or less was seen per hour. 



Regional summaries. — In the Arabian Sea, Jouanin's petrel (Bul- 

 weria fallax) and the red-billed tropicbird (Phaethon aethereus) were 

 the two species most commonly encountered in January although, 

 close to the Gulf of Aden and Socotra, Audubon's shearwaters (Puf- 

 ftnus Iherminieri) were quite common and the lesser black-backed gull 

 (Larus fuscus), Aden gull {Larus hemprichii), masked booby (Sula 

 dactylatra) and brown booby (Sula leucogaster) also were found. The 

 primary difference within this general region in the following May 

 was the appearance of several storm petrels, i.e., Wilson's petrel 

 (Oceanites oceanicus), frigate petrel (Pelagodroma marina), and either 

 the white-bellied storm petrel (Fregetta grallaria) or the black-bellied 

 storm petrel {Fregetta tropica) . Storm petrels also were seen at this 

 time south along the African coast to Mombasa and east to the 

 Seychelles Islands (see table 4) . 



Most of the breeding seabirds of the Seychelles Islands forage in 

 large mixed flocks in the relatively shallow waters around these 

 islands. Few species, however, except the sooty tern (Sterna fuscata) 

 and the wedge-tailed shearwater (Puffinus pacijicus), stray into the 

 surrounding open seas with any regularity. Although flocks of up 

 to several hundred sooty terns were seen near the Seychelles and east 

 to the African coast in May and June, no sooty terns were seen in this 

 region in January and February. 



In the equatorial regions two all-dark storm petrels of uncertain 

 identification (possibly Oceanodroma monorhis and 0. matsudairae; 

 see "Species Accounts") were encountered, as well as a tern, appar- 

 ently the fairy tern (Gygis alba). 



The numbers of seabirds found in the waters near the Mascarene 

 Islands seemed impressive to me after having passed through the 

 relatively barren region south of the Seychelles Islands. Flocks of 

 sooty terns and wedge-tailed shearwaters, as well as scattered white- 

 tailed tropicbirds (Phaethon Upturns), appeared within 50 miles of 

 Mauritius. A few common noddies (Anous stolidus) also were seen. 

 Further to the southwest, Barau's petrel (Pterodroma baraui) from 

 Reunion was a common pelagic species, occurring with tropicbirds 

 (P. lepturus) and Audubon's shearwaters (Puffinus Iherminieri). 



Below 34° S we encountered the albatrosses and petrels, charac- 

 teristic of the cool water oceans of the southern hemisphere. The 

 wandering albatross (Diomedea exulans), white-chinned petrel (Procel- 

 laria aequinoctialis) , soft-plumaged petrel (Pterodroma mollis), and 



2 The increase near the Maldives was only subjectively apparent, as standard- 

 ized watches permitting computations of birds seen per hour were not made 

 In this region. 



