Common (Hawaiian) Moorhens recorded per party hr on the Kapa'a Christmas Count (see Count
Page) in 1971-2014, showing a
significant increase from 2002 to 2014. Fluctuations in populations,
similar to those on the Lihue and Waipi'o
Christmas Counts, are related to rainfall levels in the state. Wetter
periods (such as 1976-1984 and 1991-1996) are more favorable for moorhens
than drought periods (see also Hawaiian Coot and Hawaiian Stilt). 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/