Adult Red-footed Boobies counted primarily at the Ulupau Head (KMAC) breeding colony, as recorded on the
Honolulu Christmas Count, O'ahu, 1944-2007 (see Count
Page). Numbers show wide inter-annual
fluctuation but no apparent trend. Graphs of Christmas Count data
developed as part of The Birds of the Hawaiian Islands: Occurrence, History, Distribution, and
Status by Robert L. Pyle and Peter Pyle http://hbs.bishopmuseum.org/birds/rlp-monograph/2009/