. Atoll research bulletin. Coral reefs and islands; Marine biology; Marine sciences. 246 Nesting areas used by Great Frigatebirds on Sand Island during POBSP studies are shown in Figures 44 and 79. Reasons for changes from site to site are not clear, but probably the knoll site was preferred. Intensive disturbance there by POBSP personnel in 1963- 1964 may have caused the move to the south shore. Why more birds did not nest on the southwest islet, which presents what appears to be the best raised sites on the island, is not clear. Possibly competition with Brown Boobies nesting there is respon
. Atoll research bulletin. Coral reefs and islands; Marine biology; Marine sciences. 246 Nesting areas used by Great Frigatebirds on Sand Island during POBSP studies are shown in Figures 44 and 79. Reasons for changes from site to site are not clear, but probably the knoll site was preferred. Intensive disturbance there by POBSP personnel in 1963- 1964 may have caused the move to the south shore. Why more birds did not nest on the southwest islet, which presents what appears to be the best raised sites on the island, is not clear. Possibly competition with Brown Boobies nesting there is responsible. During POBSP studies, a few Great Frigatebirds attempted to nest on navigational aids and guywire bases in the lagoon, but the few eggs laid were lost before hatching. Because of the almost total lack of bushes, at least in the areas that are far enough from human disturbance for frigates to be attracted to them, the birds on Sand Island are forced to nest entirely on the ground (Figs. 80 and 81). Since the original vegetation of the atoll contained no shrubs or trees, frigates have never had anything but the ground or Lepturus clumps on which to nest. Exceptions to this occurred during the late 1950's after the Navy abandoned Sand Island when frigates nested on overturned towers and during the early 1960's when they nested on bushes on Johnston Island. That the Johnston Atoll birds would readily nest on raised sites is shown by their use of these girders and towers in 1957 (Moynihan, 1957), and by their attempts to use the bushes on Johnston in 100 200 Feet Figure 79. Great Frigatebird nesting areas, Sand Island, Johnston Atoll, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Smithsonian Institution. Press; National Research Council (U. S. ). Pacific Science Board; Smithsonian Inst
Size: 1632px × 1531px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauth, bookauthorsmithsonianinstitutionpress, bookcentury1900
