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Guadalcanal Moustached Kingfisher Actenoides excelsus



Justification

Justification of Red List Category
This spectacular species is judged to be Endangered on the basis of a very small estimated population which is suspected to be declining, at least in part of its range. However, further research may reveal it to be more common.

Population justification

At the site above Betilonga, calls were heard from up to six locations from a camp at 1,500 m, but some calls might have been from the same individuals, and much forest at this altitude was assessed as unsuitable for this species (G. Dutson in litt. 1998). 15 km away, an area of approximately 1 square kilometer was subject to intensive observational survey in 2015.  Several groups of calling individuals were detected. Along a 2 km transect along a ridge line from 1200 to 1500 m, an average of 4-6 calling individuals was heard calling at dusk and dawn. This suggests that the species likely occurs across mid-montane Guadalcanal. This suggests a probable minimum of approximately 1,000 mature individuals based a conservative estimate that the approximate 1,200 km2 of available habitat (based upon a coarse GIS analysis of elevation zone area on Guadalcanal) is only 30% occupied (due to complex rugged topography, landslides, and likely influence of aspect on habitat suitability for this species) and that densities are on the order of four mature individuals per km2. A more likely estimate is an average of 4-6 pairs per km2 across 30-40% of potential habitat, which case the population would number about 2,000-5,760 mature individuals (C. Filardi in litt. 2016). Therefore, it is placed here in the range 1,000-5,760 mature individuals.

Trend justification
Given the lack of major recent, human disturbance across potential habitat for this species (direct anthropogenic habitat transformation has likely declined significantly in the wake of nearly all inland villages and garden sites being abandoned between the 1950s and early 1980s), it is likely that current population numbers, whatever they are, are near historic numbers for this species since human colonization of Guadalcanal thousands of years ago. Nonetheless, mining, logging in lower elevations and a changing climate all threaten portions of available habitat, leaving this species vulnerable to population declines should conservation measures fail (C. Filardi in litt. 2016). It is potentially impacted by introduced mammals such as cats which are relatively common even in undisturbed montane forest (G. Dutson in litt. 2016). Given the lack of information on this species, it is assessed precautionarily as potentially suffering an ongoing decline.

Distribution and population

Actenoides excelsus is only found on Guadalcanal in the Solomon Islands (Dutson 2011). There are three specimens from Guadalcanal, the last taken in 1953 (Mayr 1945, Cain and Galbraith 1956), and then no definite records until 1994. It is very unobtrusive and crepuscular and likely to be overlooked unless the call is known. In 1994 and 1997, it was found to be frequent in montane forest above the abandoned Betilonga village on Guadalcanal (D. Gibbs in litt. 1994, Gibbs 1996, G. Dutson in litt. 1998, Dutson 2011). In September 2015, this species was recorded by an expedition into mid-elevation forests on Guadalcanal about 15 km ENE of the site above Betilonga (C. Filardi in litt. 2016).

Ecology

Observations and reports from Guadalcanal indicate that it only occurs in closed-canopy forest between 900-1,600 m (C. Filardi in litt. 2016). Apparently absent from the many patches of more open forest, secondary scrub and bamboo that occur in areas damaged by cyclones and land-slides (D. Gibbs in litt. 1994, Gibbs 1996, Dutson 2011). On Guadalcanal, it is reported to nest in holes in the ground, sometimes in forest but usually in riverbanks (Gibbs 1996). 

Threats

Mining, logging in lower elevations and a changing climate all threaten portions of available habitat (C. Filardi in litt. 2016). It is potentially impacted by introduced mammals such as cats which are relatively common even in undisturbed montane forest (Leary 1991, G. Dutson in litt. 2016). 

Conservation actions

Conservation Actions Underway
None is known.

Conservation Actions Proposed
Survey other montane sites, especially from the south coast,with emphasis on upper Itina catchments and the un-surveyed, far eastern uplands. Survey prevalence of introduced mammalian predators in mountains. Research population densities and basic ecology at sites within the upper Tina, Tenaru, and Sutakiki catchments. Establish a system of community-based conservation areas (G. Dutson in litt. 2016).

Identification

27 cm. Beautiful but very cryptic forest kingfisher. Very few sightings, and male plumage remains undescribed. The adult female has a rufous head with a distinctive black moustachial and postocular stripe that joins to form a collar on the nape.   Greenish-black on the mantle, with a rufous 'cape' extending down from the hindneck. Similar spp. A. bougainvillei is very similar but has blue moustacial and postocular stripes, a greenish-rufous mantle and darker wings. Sacred Kingfisher Todiramphus sancta has paler buff underparts and collar. Variable Kingfisher Ceyx lepidus is much smaller. Voice Birds call before dawn and after dusk: a loud, ringing series of ko-ko-ko... notes. Hints Birds call daily but are very difficult to see above Betilonga. Learn the call and listen before dawn.

Acknowledgements

Text account compilers
O'Brien, A., Taylor, J., Stattersfield, A., Derhé, M., Mahood, S., Martin, R, Dutson, G., Symes, A.

Contributors
Filardi, C., Gibbs, D., Bishop, K.D., Dutson, G.


Recommended citation
BirdLife International (2018) Species factsheet: Actenoides excelsus. Downloaded from http://www.birdlife.org on 18/12/2018. Recommended citation for factsheets for more than one species: BirdLife International (2018) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/12/2018.