0 
\jLs 
Similar observations wero made on the Pisonia stands of Palmyra Isianct 
zoept that the layers of humus were not as thick. w 
Observations on twenty odd central Paoific atolls seoms to hear 
out the conclusions of Fosberg (1957) that the sooty tern is relatively 
unimportant in the deposition of large* concentrated amounts of guano 
on atolls. Personal observations seems to indicate that massed amounts 
of humus and guano are formed by the greater and lessor frigatebirds and 
by the redfooted booby. The bluefaced booby also tends to evacuate on 
bare cleared areas about the nest site. On Phlmyra Island large deposits 
of guano pepper the surface of the Eastern Island which supports a Pisonia 
forest and large rookeries of Redfooted boobies. A similar phosphatic 
mnant of 
boobies were 
nesting in tho upper canopyJ“XSn'"Caroiino~Island and otherjrtolls sooty 
terns nest under vegetation of Toumefortia and Scaevola A but no °Sxgn of 
phosphatization of the layers was observed, The presence of guano on 
Caroline^iSSy ho, supposed to have been deposited when afi oxtensivo- Pisonia 
forest existed on the island or under very dry conditions as reported 
for the Phoenix Island deposits. 
Guano deposition is hard to determine varying with size and number of 
birds and tho climatic zone in which the deposition is made. Very little is 
known about the annual deposition of guano of any certain species. 
ys* -ts 
Rougier mentions the Toumefortia in connection with phosphatized 
soilss "There is always a certain amount of phosphate where it grows." 
Heavy phosphatic odor and humus layer under- Toumefortia noted onttu 
east end of Palmyra Island. PhoOTheti^e^^^ter and deep humus on Vaiari 
Island, Tongareva Atoliaftn Palmyra reafooted boobies accounted for most 
of the accumulation whereas on Tongareva it was the oomjnog_noddv_J:em whose 
nests were thick along the branches of^fendanus"»^^»plant navix 
l& plant "having 
many yellowed leaves,aadr-m ost of the li tter —a&d-haa us derivgd from sam a*- 
In both cases there was no evidence of phosphatization^nor in Pemohis 
groves on Vaiari Island where redfooted boobies and greater frigatebirds 
were nesting. On Cook Island, Christmas Atoll common noddy terns were 
using Turhinaria erial'-and —To-orrief^ortxa leaves^ Ho noticeable 
phosphatization has occurred/pn^Jlcrtru Tabu as yet but the litter layer and 
underlying humus are thick. -The^-parent- m a t eria l 
♦5*W 
"fn l/wtHC ''— •K. 
V°l 
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