Red-vented Bulbuls recorded per party hr on the Waipi'o Christmas Count, O'ahu,

1977-2014 (see Count Page), showing increases during the 1970s and 1980s as populations were still expanding, followed by fluctuating and possibly generally declining populations.

 

Species account

 

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/