(to 4 m tall). These two simple plant communities cover 35% 

 and 55% of the land area, respectively. For its size, the motu 

 is sparsely vegetated, with only four plant species (one shrub, 

 three herbs), 15% of Caroline's total flora. There are no 

 introductions. 



Bo'sun Bird's most notable attributes are its 4 species of 

 breeding seabirds: red-tailed tropicbird (47 pairs in 1988, but 

 130 pairs seen in 1990), sooty tern (8,400 pairs), brown noddy 

 ( 10 pairs), and white tern (6 pairs). 



4. WINDWARD ISLET ( 1 1.42 ha) (Figs. 29,43) 



We named this "Windward" because it is the first major, 

 and largest. Windward Islet. 



Physiography : Windward is broadly crescentic in shape. 

 508 m long by 287 m wide. It parallels the reef's longitudinal 

 axis and is set close to the lagoon. Its seaward beach is quite 

 narrow (3 m wide); there is no lagoon beach. 



Vegetation: Windward has 1 1 species of plants (3 trees, 

 1 shrub, 7 herbs), 41% of the total flora. A windward crescent 

 of halophytic herbs borders a zone of Tournefortia scrub, 

 which mixes quite densely with Pisonia and Cordia over most 

 of the interior in a bilobed pattern. These latter forests, 

 reaching 14 m high in the south and 9 m in the north, total 

 8.67 ha. This unusual distribution of central forests undoubtedly 

 reflects Pisonia' s recovery from 1 00% land clearing for Cocos — 

 1,299 palms— in 1920 (Young, ca. 1922, Table 13). It is 

 remarkable that not one Cocos remains as a legacy of this 

 disturbance. 



The east-west profile of Windward, similar to that of 

 Tr. 8, Long Island (Fig. 41 ), is typical of most motus, except 

 that lagoon-facing herb flats are almost nonexistent. Scaevola 

 sericea sericea, a new plant record for the atoll, is unique to this 

 motu, although S. s. tuamotensis was found on South Island in 

 1990. 



Birds : Five species of breeding birds were present, all in 

 appreciable numbers (pairs): red-footed booby (163), great 

 frigatebird (207). brown noddy (20), black noddy (28), and 

 white tern (134). 



Comments : In May 1990, AKK noted a possible motu 

 midway between Windward and Crescent Islets during midtide. 

 It appeared to be upraised reef like Noddy Rock, but because 

 of extensive shallow reefs in this area, it has not yet been 

 confirmed. 



5. CRESCENT ISLET (3.10 ha) (Figs. 29.43) 



We named this islet for its cupped shape. 



Physiography : Crescent Islet is 1 90 m long by 225 m wide. 

 It is almost entirely composed of coral rubble, with a little 

 humus in the interior. The seaward beach is variable (up to 

 50 m wide), the lagoon beach, insignificant. 



Vegetation : There are 10 species (3 trees. 1 shrub. 

 6 herbs), 37% of Caroline's flora. No introduced plants occur. 

 Plant diversity is poorer than on Windward, a reflection of 

 small size, poor soils, and scant herb mats. However, woodlands 

 cover two-thirds of its area, and the centra] stand of Pisonia and 



Cordia is 87 m wide and up to 1 3 m high. Crescent was heavily 

 planted (80% of total area, 228 palms) in Cocos in 1920. but 

 today none remain. 



Birds : Crescent Islet was used by the following numbers 

 of breeding pairs: red-footed booby (28), great frigatebird (5). 

 brown noddy (36), black noddy (60), and white tern (8). 



6. MOTU ATIBU "Coral Rubble Islet" (0.02 ha) 

 (Figs. 27,43) 



Motu Atibu was Caroline's smallest and least vegetated 

 islet. Third in the windward chain, it measured 13 m x 18 m. 

 We named it for its basic rubble character. Vegetation covered 

 only 2% of the land surface and consisted of a few Tournefortia 

 shrubs (<1 m high) encircled by narrow swaths of low herbs 

 and rubble. Its three plant species (one shrub, two herbs) — 

 1 1% of Caroline's flora — were among the most meager on the 

 atoll. Atibu' s profile was similar to that of Fishball (Fig. 56). 

 There were no breeding birds. 



Comments : Since a February 1990 storm. Atibu has 

 apparently disappeared, having been reduced to a thin strip of 

 coral gravel below high tide level. 



7. NORTH PIG ISLET (5.44 ha) (Figs. 29,44; Pis. 60.61 ) 



We named the fourth windward islet "North Pig" for its 

 location immediately north of Pig Islet. 



Physiography : Classically crescentic. North Pig is 350 m 

 long and 230 m wide. Though approximately half Pig's area 

 and less wooded overall. North Pig has a similar distribution of 

 substrates (including sand on the lee side), vegetation, and 

 breeding birds. Profiles of the two motus are nearly identical 

 (Fig. 45). 



Vegetation : There are 1 1 plant species (3 trees, 1 shrub. 

 7 herbs), 41% of Caroline's flora. No introduced plants are 

 present. Proceeding south along the windward islets, lagoon- 

 side herb mats develop and islet cross-sections assume a more 

 perfect symmetry — low at the edges and forming a hump in the 

 middle. 



North Pig's three vegetation zones are predictably 

 symmetrical: a peripheral band of herbs (more extensive on the 

 "horns"), curved belts of Tournefortia, and a spacious central 

 forest of mixed Pisonia, Cordia, and Tournefortia. The latter 

 (to 20 m tall) covers more than one-half the islet's width and 

 one-third its area and includes fine Cordia groves (Fig. 44). 

 This excellent forest is surprising because 402 Cocos palms 

 were planted on 93% of North Pig's usable land in 1420 

 (Young, ca. 1922, Table 13). Measurements from 25 Pisonia 

 trees (main trunks) averaged 19 m in height, 221 cm in 

 circumference (at 1.5 m), and 261 cm in base circumference 

 (Table 12). 



Birds : Five species of seabirds bred: red-footed booby 

 ( 3 1 pairs), great frigatebird ( 1 7 pairs), brown noddy (76 pairs). 

 black noddy (3,199 pairs), and white tern (1 10 pairs). The 

 largest colony of black noddies on Caroline nested in the tall 

 Pisonias. 



Comments: Rats and coconut crabs were common. 



38 



