VU
Strong-billed Honeyeater Melithreptus validirostris



Justification

Justification of Red List Category
Within the last ten years the species is thought to have rapidly declined primarily due to deforestation, and this is suspected to continue. For this reason the species is evaluated as Vulnerable.

Population justification
Much uncertainty. The estimate used here is the product of three AOO measures (spanning 3,600-7,200 km2) from Newman et al. (2021), the smallest being the number of 2x2 km squares for which there are records, the latter being an arbitrary doubling of this value to account for incomplete survey effort of potentially suitable habitat. The density estimate used of 45 birds/km2 (range 18-88 birds/km2) was estimated by expert consultation (G.B. Baker unpublished in Newman et al. 2021). The population size is therefore placed between 135,000 and 270,000 mature individuals, with a best estimate of 165,000 (following Newman et al. 2021) .

Trend justification
In the last decade, reporting rates from available systematically collected 2-ha 20-min surveys, 500-m radius and 5-km area searches (BirdLife Australia 2020) declined by 72% (500-m) and 51% (5-km) in north-western Tasmania; by 38% (500-m) at Pyengana in north-eastern Tasmania; and, in south-eastern Tasmania, by 96% (2-ha) at Meehan Range. The reporting rate on kunanyi/Mount Wellington declined by 89% between 1976–1978 and 2014–2016 (Newman 2017). Data for an array of 2-ha surveys sites on the Wellington Range were inconclusive over 2014–2019 (Newman et al. 2021). A composite trend for those sites with sufficient data indicated that the species has decreased by 51% over the last decade (2009–2019). Given that similar trends are apparent at widely dispersed locations, but that there is some inconsistency, it is concluded that the population as a whole has declined by 30%–49% in the last decade (Newman et al. 2021). Given the ongoing threats of habitat loss, fire and drought (Newman et al. 2021), declines are feared to continue over the next three generations.

Distribution and population

The species occurs across most of Tasmania, King Island and Flinders Island, Australia. There are few records from the poorly surveyed south-west, and they are absent from the agricultural regions between Ouse and Andover, south of Launceston and west of Bicheno (Higgins et al. 2001, BirdLife Australia 2020). Most birds are thought to be largely sedentary, although there may be local seasonal movements to and from traditional breeding areas (Higgins et al. 2001).

Ecology

The species occurs in sclerophyll forests, especially in gullies, moving into the drier forest on slopes during winter in some areas where they feed mostly on arthropods, mainly insects, largely obtained by foraging on tree trunks and bark (Higgins et al. 2001, Davis 2013). Individuals build small, deep cup-shaped nests in tall trees or dense bushes in which they usually lay three eggs. Breeding occurs in small colonies in 'traditional' areas, with colony members returning to the same general location each year (Higgins et al. 2001). They are adversely affected by logging in wet forests where they are very uncommon in young silvicultural regrowth (Hingston 2000, Lefort and Grove 2009, Hingston and Grove 2010), increase in abundance as regrowth develops (Hingston and Grove 2010) but are still less common in older regrowth (25–50 years post-harvest) than in mature forest (Wardlaw et al. 2018). Their abundance in silvicultural regeneration is proportional to the proportion of mature forest in the surrounding landscape (Wardlaw et al. 2018). Occurs to at least 1,240 m (eBird 2021).

Threats

Deforestation in northern Tasmania (Michaels et al. 2010) is thought to have been the main reason for the decline in that region given the species' reliance on older forests. In eastern Tasmania, drought, which is likely to increase in frequency and severity (Evans et al. 2017), may have exacerbated declines with six out of the last ten years being below average rainfall at most weather stations. Fire, both periodic fuel reduction burns (Newman et al. 2020) and wildfires, which can have impacts lasting decades (Newman 2017), affects the availability of prey hidden in bark.

Conservation actions

Conservation Actions Underway
Some subpopulations and their habitat conserved as World Heritage Area or National Parks.

Conservation Actions Proposed
Monitor population trends in combination with research to determine reasons for population decline. Understand demography and ecology with respect to climate variables, particularly drought. Assess relationship with fire, especially prey recovery times. Develop appropriate management interventions. List as threatened under appropriate conservation legislation. Secure key occupied habitat patches from degradation and loss.

Acknowledgements

Text account compilers
Vine, J.

Contributors
Butchart, S., Ekstrom, J. & Wheatley, H.


Recommended citation
BirdLife International (2022) Species factsheet: Melithreptus validirostris. Downloaded from http://www.birdlife.org on 17/08/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 17/08/2022.