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.
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/