Zebra Doves recorded per party hr on the Honolulu
Christmas Count, 1944-2007 (see Count
Page), indicating increasing trends during the
1940-1980s followed by a decline during the 1990-2000s.
See also 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/2009/