House Sparrows recorded per party hr on the Honolulu
Christmas Count, 1944-2014 (see Count
Page), indicating increases during the
1950-1970s following by declines during the 1980-2010s, and a significant
decline overall. See also Moulton and Scioli
(1986), Williams (1987), and Ralph (1990). 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/