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Australasian Plant Conservation

Originally published in Australasian Plant Conservation 22(2) September - November 2013, p 9-11

Regent Honeyeaters and Eucalypt diversity in the Cessnock area of New South Wales

Mick Roderick
BirdLife Australia, Carlton, Victoria. Email: mick.roderick@birdlife.org.au

Regent Honeyeater - listed nationally as Endangered and as Critically Endangered within New South Wales. Photo: Allan Richardson

Regent Honeyeater feeding on blossom at Kurri Kurri. Photo: Mick Roderick

The Regent Honeyeater (Anthochaera phrygia) is an endangered species of honeyeater that occurs in Eucalypt-dominated open forests and woodlands from south-east Queensland to Central Victoria (and formerly into South Australia where it is now considered extinct). It is listed nationally as ‘Endangered’ and as ‘Critically Endangered’ within New South Wales (NSW) due to critical decline in numbers and area of occupancy. It is generally accepted that the total population of Regent Honeyeaters is fewer than 1000 birds, possibly much less.

Occurrence within Cessnock Local Government Area

Regent Honeyeaters occur regularly within the remnant forested areas within the Cessnock Local Government Area (LGA), within a 20 km radius of Kitchener (32º 52’ 10” S, 151º 22’ 12” E e.g. Roderick & Ingwersen 2012). The area is considered crucial to the viability of Regent Honeyeaters both as an adjunct to the Capertee Valley breeding area and as an important area in its own right (Ingwersen et al in prep; Roderick et al 2013).

Preferred habitat- Spotted Gum Forest

In this area, Regent Honeyeaters occur sporadically within dry open forests in association with the seasonal blossoming of winter-flowering Eucalypts. These forests are generally dominated by Spotted Gum (Corymbia maculata), Broad-leaved Ironbark (Eucalyptus fibrosa) and Grey Gum (E. punctata). However, the diversity of Eucalypts in the area is considered to be very high and botanical studies in the area have recorded up to 43 species of Eucalypt, comprising 35 Eucalyptus (including 2 undescribed species), five Angophora and three Corymbia species (DECC 2008). This represents an astonishing diversity in such a small area (<400 sq. km). In fact, a single remnant patch of bushland (the Hunter Economic Zone; HEZ) was found to contain 29 species, including both of the undescribed taxa, within a 3000 ha area (Bell 2004) and has been recognised as a high priority conservation area that contains complementary World Heritage Values to the Greater Blue Mountains World Heritage Area in the Cessnock LGA (Parsons Brinckerhoff 2013).

The reasons for this high diversity of Eucalypts are not known, but it is worth noting that Cessnock is at the junction of the Sydney Basin and North Coast IBRA bioregions and that the area forms the limit of distribution for many plant taxa (in all compass directions). Given that Regent Honeyeaters occur almost exclusively in habitats dominated by Eucalypts (see Higgins et al 2001), the high diversity of Eucalypts could be a factor in the significance of the Cessnock forests to Regent Honeyeaters. The fact that the forests occur in large vegetated remnants on the floor of the Lower Hunter Valley is likely to also be a major contributing factor as the forests occur on fertile soils in an over-cleared landscape (and hence contain fauna species, such as the Regent Honeyeater, associated with fertile soils).

Predominantly, it appears to be the prolific blossoming of Spotted Gum that attracts Regent Honeyeaters to the Cessnock area in high numbers. This occurs on a cyclical basis, as Spotted Gums do not flower en-masse every year. In recent times, significant numbers of Regent Honeyeaters have been recorded in the Cessnock area during 2000, 2003, 2007, 2009 and 2012. During 2012 at least 100 Regent Honeyeaters were recorded in the Cessnock area, constituting the maximum known concentration of the species anywhere across its range since 2005 (which was in the Capertee Valley) and comprised a significant proportion (probably >10%) of the total population of the species.

Importance of other species for foraging

Apart from the availability of Spotted Gum, Regent Honeyeaters have been observed feeding in the blossom of other Eucalypts in the Cessnock area such as Forest Red Gum (Eucalyptus tereticornis) and Broad-leaved Ironbark (E. fibrosa). They have also been observed feeding in Eucalypts that have not been previously documented as feed trees. These include the blossom of Eucalyptus fergusonii ssp. dorsiventralis (Rare or Threatened Australian Plant, ROTAP rating 2RC) and an undescribed species of stringybark, E. sp. aff. agglomerata.

The identification of stringybark trees that have been used regularly by Regent Honeyeaters in the Cessnock area is complex. Trees in the Kitchener / Ellalong / Paxton area have been identified as appearing more like Brown Stringybark (E. capitellata) and it is uncertain which species these trees belong to. They have also been recorded for several years in tall stringybark trees along a drainage line in the Quorrobolong area, which show more affinities to E. agglomerata but again, which have not been identified to date. In other areas, Thin-leaved Stringybark (E. eugenoides) has been tentatively identified as trees where Regent Honeyeaters have been found feeding.

Another Eucalypt-related food resource occurs in the area in the form of Long-flower Mistletoe (Dendropthoe vitellina) plants. These mistletoe clumps are abundant in the Cessnock forests and are predominantly hosted within Spotted Gum trees. However, Regent Honeyeaters have been observed foraging on the blossom of Long-flower Mistletoe plants within Narrow-leaved Apple (Angophora bakeri) trees (M. Roderick; S. Roderick; A. Richardson pers. obs.).

Breeding

Regent Honeyeaters have bred on several occasions in the area, usually when other blossoming occurs in spring-flowering Eucalypts. In late 2007, a successful “semi-communal” breeding event took place on industrial-zoned land within the HEZ. This area was likely used as a breeding locality in the past (A. Zoneff pers. comm.). Nests were located within Broad-leaved Ironbark and Grey Gum trees and/or within Narrow-leaved Mistletoe clumps (Biosis Research 2008). This represented one of the most important and successful known breeding events for Regent Honeyeaters in recent times and further highlights the significance of the Cessnock area to underpin recovery efforts for the species.

Conclusions

The Eucalypt-diverse open forests of the Cessnock area are regularly used by Regent Honeyeaters and are of crucial importance to this critically endangered species, both in terms of providing an essential winter food source and significant opportunity for birds to breed. The area is recognised as being of high conservation value generally and the significance for Regent Honeyeaters cannot be understated. Recent strategic planning assessments have recommended that areas of high conservation value not currently protected be considered for conservation. Further work should be undertaken to clarify the taxonomic and conservation status of the various stringybark species known to be used regularly by Regent Honeyeaters in the area.

References

Bell, S.A.J. (2004). The vegetation of the Hunter Economic Zone (HEZ), Cessnock LGA, New South Wales. Report to Harper Somers O’Sullivan.

Biosis Research (2008). Targeted surveys for Regent Honeyeater within the Hunter Economic Zone (HEZ) - survey results. Report prepared for Valad Property Group. Biosis Research, Sydney.

Department of Environment and Climate Change (2008). Vegetation of the Cessnock-Kurri Region, Survey, Classification & Mapping, Cessnock LGA, New South Wales. Department of Environment and Climate Change (NSW), Sydney.

Ingwersen, D.A., Geering, D.J. and Menkhorst, P. (in prep.). Draft National Recovery Plan for the Regent Honeyeater Anthochaera phrygia 2013-2017. New South Wales Office of Environment and Heritage: Dubbo, and BirdLife Australia: Melbourne.

Parsons Brinckerhoff (2013). Greater Blue Mountains World Heritage Area Values Study in the Cessnock Local Government Area and Surrounds. Report for Department of Sustainability, Environment, Water, Population and Communities.

Roderick, M., Ingwersen, D.A. and Tzaros, C.L. (2013). Swift Parrots and Regent Honeyeaters in the Lower Hunter Region of New South Wales: an assessment of status, identification of high priority habitats and recommendations for conservation. Report for Sustainable Regional Development Program. Department of Sustainability, Environment, Water, Population and Communities. BirdLife Australia, Melbourne.

Roderick, M. and Ingwersen, D.I. (2012). Observations of Regent Honeyeaters in the lower Hunter Valley of New South Wales during winter 2012. The Whistler 6: 44-45.

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