NT
Black-throated Shrikebill Clytorhynchus nigrogularis



Justification

Justification of Red List Category
This species is listed as Near Threatened because it has a small and declining population owing to losses of mature old-growth forest through continuing logging and forest conversion. Population declines are inferred to approach the threshold for Vulnerable (under criterion C1) and if declines are found to be greater than currently estimated it may warrant uplisting.

Population justification
Recent surveys on Fiji recorded an average of 0.1 birds/hour (a total of 49 birds) equating to one bird/km2, mostly calling males. There are a number of likely errors in this estimate, especially the number of silent birds overlooked. The species was recorded at 55% of the sites surveyed (19/34 sites) which were pre-selected to be the densest wettest old-growth forest. Very few were recorded in logged or degraded forest. If it assumed to occur in 50% of the forest, which covers about 40% of the species's Fijian extent of occurrence (EOO) (c. 17,500 km2), the total population is likely to be in the range of 2,500-9,999 birds (G. Dutson in litt. 2005). This equates to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals.

Trend justification
Given the species's intolerance of habitat degradation, it is likely to be declining at the same rate as forest loss and degradation, which is estimated to be about 0.5-0.8% per year (Claasen 1991), equating to 6-10% over 12 years (three generations).

Distribution and population

This species is found on Viti Levu, Vanua Levu, Taveuni, Kadavu and Ovalau in Fiji (Pratt et al. 1987). It has been described as fairly common in suitable habitat, but is likely to be rarer than commonly reported because it is usually misidentified and occurs at low population densities (G. Dutson pers. obs. 2000, Watling 2000). Recent surveys have generated much more data on this species, showing it to be widespread but at low population densities: approximately one bird/km2 on average and it is fairly common at the Garrick and Tomaniivi reserves; one or two can be heard most days in the central hills from Nausori Highlands to Nadrau and Monosavu. The species was recorded at 55% of the sites surveyed (19/34 sites) which were pre-selected to be the densest, wettest old-growth forest. Very few were recorded in logged or degraded forest. The total population is likely to be in the range of 2,500-9,999 birds (G. Dutson in litt. 2005). The species is likely to be declining at the same rate as forest loss and degradation, which is estimated to be about 0.5-0.8 % per year (Claasen 1991). There are very few recent records from Vanua Levu, Taveuni, Kadavu or Ovalau.

Ecology

It occurs up to 1,200 m in dense, mature, wet forests (Pratt et al. 1987). It has also been reported from mangroves and dense bush (Clunie 1984), however, it appears to be absent from extensive areas of degraded forest without scattered remnants of old-growth forest, and has a patchy distribution, probably being more common in mountains (G. Dutson pers. obs. 2000, D. Watling verbally 2000, G. Dutson in litt. 2005).

Threats

The main threat is the continuing habitat loss and deterioration from logging and mahogany plantations, with only c.50% of Viti Levu and Vanua Levu remaining forested (Watling 2000). However, according to the Department of Forestry, the logging rate is slowing, and there is only one active logging operation on Vanua Levu (V. Masibalavu in litt. 2007). Government priorities regarding Protected Areas in Fiji are undefined and so these areas are under threat, for example in the Sovi Basin Protected Area where the possibility of mining in the area is being explored (V. Masibalavu in litt. 2012). Invasive alien plant species, feral animals and species including Common Myna Acridotheres tristis and Red-vented Bulbul Pycnonotus cafer may also threaten the species (Gregory 2006).

Conservation actions

Conservation and Research Actions Underway
It is protected by law and is recorded from several protected areas including Tomaniivi and Ravilevu Nature Reserves, the Sovi Basin and the Garrick Memorial Park (D. Watling in litt. 2000, V. Masibalavu in litt. 2007). BirdLife Fiji is working towards establishing three new PAs (Natewa Peninsula and two sites in Kadavu) with an effective monitoring framework (V. Masibalavu in litt. 2007).

Conservation and Research Actions Proposed
Develop a monitoring programme for forest birds as declines in population and the initiation of threat processes could well be going unnoticed (SPREP 2000). Develop in-country training in survey techniques (SPREP 2000). Survey populations on all five islands. Determine population densities in various forest habitats and altitudes. Monitor populations at well-known sites, e.g. Nausori Highlands. Advocate creation of community-based forest conservation reserves. Initiate management in gazetted nature reserves (D. Watling in litt. 2000).

Identification

21 cm. A heavy greyish-brown forest bird. Bllack head and throat of adult male contrasts strongly with grey-white ear-coverts, otherwise, uniform grey-brown plumage. Female and immature more consistently brownish and lack head pattern. Heavy, black bill with horn edgings and tip. Similar spp. Female only safely distinguished from slightly smaller Fiji Shrikebill C. vitiensis by bill size and shape or by presence of male. Females can also be confused with Wattled Honeyeater Foulehaio carunculata (which should be readily distinguished by voice, curved beak and yellow wattle) and female Golden Whistler Pachycephala pectoralis (which has rounder head and flatter bill). Voice Both species of shrikebill have drawn-out, wavering, whistling call with several variations. These are not distinguishable except with considerable experience.

Acknowledgements

Text account compilers
Derhé, M., Dutson, G., Mahood, S., O'Brien, A., Shutes, S., Stattersfield, A., Temple, H. & Ashpole, J

Contributors
Dutson, G., Leary, T., Masibalavu, V. & Watling, D.


Recommended citation
BirdLife International (2019) Species factsheet: Clytorhynchus nigrogularis. Downloaded from http://www.birdlife.org on 17/09/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 17/09/2019.