The regent honeyea ter, Xanthomyza phrygia, is an
endangered woodland bird whose range and population size have decreased in the
last thirty years. Suggested reasons for this decline include abnormal
breeding behaviour, poor reproductive output, and excessive inter- and
intra-specific aggression. This study investigated the breeding behaviour and
aggressive interactions of regent honeyeaters during the nest construction,
incubation, nestling, and fledgling stages in two consecutive breeding seasons
in the Bundarra–Barraba region near Armidale, New South Wales. The
female was entirely responsible for nest construction and incubation, which is
typical of many honeyeaters. Both parents fed the nestlings, and at a similar
rate, although only the female brooded chicks on the nest. Both parents fed
the fledglings. The mean frequency at which nestlings (23 times per hour) and
fledglings (29 times per hour) were fed is the highest published rate of any
non-cooperative honeyeater. Breeding males were involved in significantly more
aggressive interactions with conspecifics and other nectarivores than were
females, although the overall percentage of day-time spent in aggression for
both sexes was low (2.5%). It appears that abnormal breeding behaviour,
poor reproductive effort, or excessive aggression are not experienced by this
species in northern New South Wales, and that other factors are likely to be
responsible for its current low population level.