NT
Whistling Dove Chrysoena viridis



Justification

Justification of Red List Category
This species qualifies as Near Threatened as it has a moderately small population which is suspected to be declining moderately rapidly. If further research shows that the population is undergoing a more rapid decline, it may be uplisted to Vulnerable.

Population justification
Recent BirdLife Fiji surveys found this species to be common in evergreen forests, with 53 birds recorded (mostly calling males) in 23.5 hours a mixed lowland and montane site and 17 birds in 15 hours at a montane site. Estimating an average pace 1 km / hour and an effective detection distance of 50 m each side of the trail suggests that around 23 and 11 birds were detected per km2 at these sites, mostly calling males. There are a number of likely errors in this estimate, especially the number of silent birds overlooked and the species' higher abundance at lower altitudes (where calling males can be as little as 100 m apart). The area of dense and medium-dense forest on Kadavu is around 225 km2, suggesting that the total population is around 10,000 birds. However the species also occurs on the island of Ono which probably constitutes a second sub-population (as this and other Chrysoena doves are rarely seen flying outside forest and have not been recorded from smaller islands), numbering about 5% of the total population (G. Duston in litt. 2005). In total the population is estimated to number at least 10,000 individuals, roughly equivalent to 6,700 mature individuals.

Trend justification
The population is suspected to be declining based on rate of habitat loss. The population trend is estimated to be declining at the same rate as forest loss and degradation on Kadavu, which is estimated to be 0.5-0.8 % per year across Fiji (Claasen 1991), but probably higher on Kadavu which has suffered extensive fires in recent years. The population may therefore be declining at a rate that approaches 10% in ten years (G. Duston in litt. 2005).

Distribution and population

Chrysoena viridis is endemic to the islands of Kadavu and neighbouring Ono in south-west Fiji. In 2000, surveys found this species to be common in evergreen forests, with 53 birds recorded (mostly calling males) in 23.5 hours in a mixed lowland and montane site, and 17 birds in 15 hours at a montane site (G. Dutson in litt. 2005), equating to 23 birds/km2 and 11 birds/km2 at these sites respectively, mostly calling males. There are a number of likely errors in this estimate, especially the number of silent birds overlooked and the species's higher abundance at lower altitudes (where calling males can be as little as 100 m apart (G. Dutson in litt. 2005). The area of dense and medium-dense forest on Kadavu is around 225 km2 (National Forest Inventory 1990-1993), suggesting that the total population is around 10,000 birds. However, the species also occurs on the island of Ono which probably constitutes a second sub-population (as this and other Chrysoena doves are rarely seen flying outside forest and have not been recorded from smaller islands), numbering about 5% of the total population (G. Dutson in litt. 2005).

Ecology

It is generally found in well-forested areas in the lowlands; on Ono it is restricted to forest remnants (Clunie 1984), and is sometimes found in gardens (Watling 1982). It forages mainly in the substage of forests and in dense thickets.

Threats

The population is estimated to be declining at the same rate as forest loss and degradation on Kadavu, which has also suffered extensive fires in recent years. Hunting may be an additional threat.

Conservation actions

Conservation Actions Underway
In 2000, BirdLife Fiji conducted surveys to estimate population size.

Conservation Actions Proposed
Continue to monitor population size to assess trends. Set aside and protect forest habitat, particularly in lowland areas. Investigate the impact of hunting on the species and regulate as appropriate.

Identification

20 cm. An inconspicuous, green fruit-dove. The male is uniformly green, although slightly darker on the back but with a yellowish-green head, a white belly and yellow undertail coverts. The female is similar but lacks the distinctive head plumage. Voice A single mellow whistle which is immediately followed by a short trill, the latter only heard at close quarters. Hints May be seen in any forest area of Kadavu and its offshore islands, generally heard first.

Acknowledgements

Text account compilers
Benstead, P., Dutson, G., Mahood, S., O'Brien, A., Shutes, S. & Symes, A.

Contributors
Dutson, G. & Kretzschmar, J.


Recommended citation
BirdLife International (2020) Species factsheet: Chrysoena viridis. Downloaded from http://www.birdlife.org on 30/03/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 30/03/2020.