Hawaiian Ducks recorded per party hr on the Kapa'a Christmas Count, Kaua'i,
1971- 2014 (see Count
Page), showing a significantly
increasing recent 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/