
Mallards recorded per party hr on the Honolulu Christmas
Count, O'ahu, 1944-2014 (see Count
Page). The observations in the 1940s may have
represented confusion with Koloa, the increase in numbers from 1986 to 2009 reflects
spreading of a naturalized population following propagation in the
1950s-1960s, and the decline since 2009 reflects control efforts in support
of Hawaiian Duck populations. 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/