human settlement (Howland and Baker are US National Wildlife 



Refuges, and Birnie, McKean. and Phoenix Islands are Kiribati 

 Wildlife Refuges), its seabirds appear reasonably safe from 

 disturbance for the present. 



Region III (495 birds. 13 species, 5 families) 



The Gilbert Islands (Fig. 1 ) stretch in a compact arc from 

 03°17'N to 02°38'S latitude and from 176°49'E to 172°48'E 

 longitude. They compose a single archipelago of 1 1 atolls and 

 5 reef islands, forming a southerly extension of the Marshall 

 Islands. 



All the Gilbert Islands are populated, some heavily. Since 

 the I-Kiribati have long utilized seabirds and their eggs for 

 food, species sensitive to human disturbance (shearwaters, 

 petrels, boobies, tropicbirds) are absent. The primary breeding 

 species are tree-nesters such as brown noddies and white terns 

 (Table 4). 



Our observations were dominated by larids (Table 3). 

 Brown noddies (48% ) and sooty terns (219c) composed 929c of 

 (locking birds. With the exception of a few boobies, most other 

 birds were nonbreeding visitors (Table 4). Migrants were 

 absent (Fig. 3). We also provide additional sightings of such 

 rarities in the region as Cook's petrel ( 1 ). Kermadec petrel (2), 

 south polar skua (5), and wedge-tailed shearwater (213) 

 (Table 6). 



Region IV (799 birds, 18 species, 10 families) 



Our cruise track passed south of the districts of Kosrae and 

 Pohnpei, then north of Truk, Yap, and Belau (04°N to 10°N 

 latitude, 163°E to 138°E longitude). Micronesia contains 

 fewer people on far more islands than the Gilberts. However, 

 fishing fleets from several foreign countries are exploiting their 

 oceanic waters, and the presence of even a few people on an 

 islet deters many seabird species from successful breeding. 



Ourobservations from the Caroline Islands were dominated 

 by sooty terns and noddies ( 52% of birds seen), but procellariids 

 and boobies were represented in fair numbers. Skuas first 

 appeared here, along with the only migrant duck. The wedge- 

 tailed shearwater attained a density of 2.93 birds/10 km- 

 ( Tabic 2). Our observations of brown boobies suggest the 

 possible existence of a colony on Magur Islet, Namonuito 

 Atoll, in the District of Truk. 



Region V ( 34 birds. 6 species. 4 families) 



The Philippine Sea and Basin (Fig. 2) exhibited the lowest 

 biodiversity and species densities (Tables 1-4) of the five 

 Pacific regions. This relatively small area, little-known 

 ornithological lv and with no islands for hundreds of kilometers. 

 stretches west of the Marianas to the Philippines (at 11°N 

 latitude, from 136°E to 125°E longitude). The nearest landfalls 

 arc the Marianas to the northwest. Belau, New Guinea, and the 

 Moluccas (Indonesia) to the south, and the Philippines to the 

 w est. Plankton productivity and fish populations arc known to 

 be considerably poorer in tropical waters north of 09°N than 

 further south (Ashmole & Ashmole, 1967). Our sightings of 

 six streaked shearwaters suggest that the southerly migration 

 corridor for this species lies entirely cast of the Philippines. 



Region \ I (22 birds. 4 species. 6 families) 



The Bohol (Mindanao) and Sulu Seas stretch from 125°E 

 to 1 17°E. Seabird densities were low. Phalaropes. not previously 

 encountered on our cruise, accounted for over half the total bird 

 count (Table 3). A few larids, skuas, brown noddies, and 

 wedge-tailed shearwaters (our most western observations) 

 completed the list. The proportions of resident breeders, 

 nonbreeding visitors, and direct migrants were equal (Fig. 4). 

 Elevated human populations in the Philippines have undoubtedly 

 reduced seabird numbers. 



Region VII (65 birds, 8 species. 5 families) 



Our cruise track passed through the South China Sea 

 between 07°N to 01°N latitude and 117°Eto 104°E longitude. 

 The route passed from the Balabac Strait (southwestern 

 Philippine Islands) indirectly to Singapore (Fig. 2). These 

 waters, the most heavily polluted of the trip ( see Chapter 2. this 

 vol.), are heavily fished commercially, and human population 

 densities around their periphery are high. Seabirds were 

 sparse. As with Region VI. phalaropes contributed half of the 

 total. Migrant stercorariids formed the next most common bird 

 grouping; since stercorariid records are few from this area, our 

 observations of 1 2 birds of at least 2 species add to their known 

 dispersal areas. 



Gulls and terns were in surprisingly few numbers, 

 considering that almost 20 species occur in the South 

 China Sea. We recorded Caspian, bridled, and crested 

 terns (and a few unidentified larids) in very small numbers. 

 Resident breeders and nonbreeding visitors numbered only 

 one species each, and there were four species of migrants 

 (Fig. 3). 



During our indirect. 9-day passage across the South China 

 Sea (23-31 October) we encountered approximately 150 land 

 birds (including 40 raptors), totaling at least 20 species (Ellis 

 et ah, 1990 and Subchapter 3.6, this vol.). The presence of 

 owls, nightjars, falcons, a large crake, and small forest birds 

 provided a highly interesting replacement for the expected 

 terns, gulls, and other seabirds. 



This area is little known ornithologically, at least in 

 English publications (Delacour&Mayr. 1946; Delacour. 1947; 

 Anon.. 1975; Jing-Xiam & Zi-Yu, 1975; Nelson. 1978; Hails. 

 1987; King & Dickinson. 1987). We added three parasitic 

 jaegers to records for the South China Sea and a possible range 

 extension of the masked booby. Unfortunately, in the last few 

 decades numerous large seabird colonies in this area have been 

 destroyed by direct human predation (Nelson, 1978) but 

 considerable efforts towards conservation of islands, reefs, 

 bays, and varied habitats are on-going commitments by all 

 countries concerned, assisted by international agencies (UNEP, 

 I984a,b; IUCN. 1988a,b). 



This First US-USSR Central Pacific Expedition resulted from 

 the efforts of main people in the United States and the Soviet Union. 

 On the American side, the primary organization and financial support 

 wore from the US Fish & Wildlife Service. We especially appreciate 

 the efforts of Harold J. O'Connor, Director, Patuxent Wildlife Research 

 Center and Steve Kohl (Office of International Affairs). We thank 

 H. Randolph Perry for suggesting and encouraging our participation 

 in the expedition, Paul Sykes for willingly assuming the Michigan 



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