- June *67 West descriptions of Red-footed Booby - Burckhalter (cont.) 
easily obtained. 
i 
As previously stated* Scaevola bushes not only provided nesting sites, 
but a great majority of the nesting material used (ca. 90 percent). What 
might be termed the upper layer or ’’cushioning’ 1 of a red-foot nest was 
* 
constructed from freshly picked Tribulus and/or Cucerbus branchings and 
sometimes Scaevola leaves. These materials did not seem functional in 
support'due to their limberness and small size. For their usage, I can 
speculate on two possible explanations: one being that they provided a 
cushion between egg and coarse nesting material, the other being that at 
nest sites already having seemingly sufficient material for nests, these 
were added as a fulfillment to the nest building requirement which pre¬ 
requisites egg-laying. Yet another reason might be that this material 
K i 
was periodically added while rearing the young as a part of pair-bond 
\ , 
■ 
maintenance. In support of the latter speculation, I noted that in most 
nests examined, fresh materials were present, these always being Tribulus 
and/or Cucerbus branchings or Scaevola leaves. 
Though accurate measurements of nest dimensions were not taken, most 
of the nests examined were approximately four inches in depth and usually 
greater than twelve inches in width. I would estimate that £a. 75 percent 
of the nest sites were the same as those used in previous years. This was 
evident due to old nesting materials on the ground below many of the nests. 
Also guano and bones showed traces of former sites. I believe that large 
nests with remains of previous generations indicated periodic nesting sites. 
At sites such as these, additions to a nest by a current nesting pair could 
often be determined fry evidences of newer materials. Frequently I found 
that few, if any, Scaevola twigs were used, usually only Tribulus and 
Cucerbus''being \added to the old nest site. In the case of newer nest sites. 
