Red-whiskered Bulbuls recorded per party hr on the Waipi'o Christmas Count, O'ahu, 1977-2007 (see Count
Page), showing fluctuation but
no significant 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/