I'iwis recorded per party hr
on the Volcano Christmas Count, Hawai'i,
1972-2014 (see Count
Page), showing an increase
through 1998 followed by a decline though 2006 and an increase though 2012. 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/