Document ID: chunk:federal_register_of_legislation:F2016L00635:reg:1:p9
Version: federal_register_of_legislation:F2016L00635
Segment Type: reg
Provision Reference: reg 1 (pt 9/23)
Character Range: 26925–29940

and forest containing the bird's preferred eucalypt species. Whilst clearing directly reduces the amount of available habitat, it can also make remaining remnants unsuitable as they become too small or isolated. The major continuing threat is further degradation of habitat, particularly on-going reductions in habitat quality and lack of regeneration. Noisy miners become more common in fragmented and degraded habitat, due to their preference for open areas adjoining woodland, and exclude birds, including regent honeyeaters, from many native vegetation remnants.

4.2  Current threatening processes
The primary threats to the regent honeyeater relate to the species' small population size, habitat loss and fragmentation, competition, and degradation of remnant habitat. These are discussed below, presented in the order of highest to lowest threat.

4.2.1  Small population size
The first population estimate for the regent honeyeater was formulated based on surveys conducted in the late 1980s; at the time it was thought there were approximately 1500 individuals across south-east Australia (Webster and Menkhorst, 1992). A more recent revision suggests that the population may currently be as low as 350400 mature individuals (Recovery team unpublished data; Garnett et al., 2011). This population is spread across millions of hectares of south-eastern Australia, meaning that the density of the regent honeyeater would be extremely low across the vast majority of their range.
Ford et al. (1993) postulated that the tendency for regent honeyeaters to nest together in aggregations (e.g. Franklin et al., 1989; Geering & French 1998) allowed  them to exclude larger honeyeaters from a nectar source without requiring excessive energy or time spent by individual pairs. With a decreasing population, regent honeyeaters may no longer be in sufficient numbers in nesting aggregations to effectively exclude other birds, or to be able to coalesce into nesting aggregations in the first place. The result is postulated to be lower reproductive output of individual pairs (Ford et al., 1993).  Further, recent research suggests that nest predation may be limiting the ability of the species to recruit well in good breeding conditions.  Species such as sugar glider (Petaurus breviceps), squirrel glider (P. norfolcensis), and magpie (Cracticus tibicen) have been recorded attempting to prey on adults and/or successfully preying on eggs, and the impacts of this may be significant (Ingwersen 2015, pers. comm.).
In addition, there are inherent issues related to small population size which may be acting to exert pressure on recovery of the species, such as the potential impact of stochastic events such as wildfire or disease, and the loss of genetic diversity. Population bottlenecks, where a population's size is reduced for at least one generation, can significantly reduce genetic diversity through genetic drift (random changes in the gene frequencies of a population from generation to generation). A