Archived 2010-2011 topics: Solomon Islands Frogmouth (Rigidipenna inexpectata): uplist to Near Threatened or Vulnerable?

Link to BirdLife species factsheet for Solomon Islands Frogmouth

Solomon Islands Frogmouth Rigidipenna inexpectata was formally recognised by BirdLife International in 2010, following Cleere et al. (2007), and immediately listed as Least Concern on the basis that it was not considered to approach the thresholds for Vulnerable under any of the criteria.

The population is suspected to be decreasing due to ongoing habitat destruction; however, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (at least a 30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (fewer than 10,000 mature individuals with a continuing decline estimated to be at least 10% over ten years or three generations, or with a specified population structure).

Mapping of the species’s range, however, to follow Cleere et al. (2007) has confirmed that the Extent of Occurrence (EOO) is less than 20,000 km2, currently estimated at 16,700 km2. This meets the EOO threshold for Vulnerable under the B1 criterion on the basis that there is also a continuing decline observed, inferred or projected in any of the following: the EOO, Area of Occupancy, area, extent and/or quality of habitat, number of locations or sub-populations, and number of mature individuals.

Further information is needed before a decision can be made on whether to list the species as Vulnerable or Near Threatened. The species will only qualify as Vulnerable if it is shown that its population is also severely fragmented, or occurs at 10 locations or less, or that there are extreme fluctuations in its range or population size. The species habitat will be regarded as severely fragmented if over 50% is in patches that are too small to support viable populations. If the species does not meet all of the B1 criterion for Vulnerable, it will likely be listed as Near Threatened.

To help in its assessment, further information is requested, particularly on the level of fragmentation in this species’s habitat and hence its population. Information is also invited on the likely population size and rate of decline over 23 years (estimate of three generations), as well as the severity of threats faced by the species.

Cleere, N., Kratter, A. W., Steadman, D. W., Braun, M. J., Huddleston, C. J., Filardi, C. E. and Dutson, G. (2007) A new genus of frogmouth (Podargidae) from the Solomon Islands – results from a taxonomic review of Podargus ocellatus inexpectatus Hartert 1901. Ibis 149: 271-286.

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3 Responses to Archived 2010-2011 topics: Solomon Islands Frogmouth (Rigidipenna inexpectata): uplist to Near Threatened or Vulnerable?

  1. Guy Dutson says:

    During several weeks fieldwork on Buka (but not Bougainville), Choiseul and Santa Isabel between 1997-2010, I have only recorded this species around the village of Tirotonga on Isabel. However, it is cryptic, calls infrequently and I have spent very little time in forest at night on these islands. Cleere et al. (2007) located 19 museum specimens but no other field records are known away from Tirotonga. It has been recorded in forest including logged forest and mosaics of forest, regrowth and gardens, to 700 m. As such, I would infer (based on observations of habitat loss and degradation, and projections from the rate of human population increase, most of whom are subsistence farmers) that it is undergoing a small but significant continuing decline in Area of Occupancy, area, extent and quality of habitat, and number of mature individuals, but not in EOO.

    Although rainforest on these islands is increasingly degraded, most remains within a patchwork of secondary forest and regrowth. Given my observations of this species moving across areas of hundreds of metres of gardens with only scattered large trees and the apparent lack of subspecific variation across its insular range, I would suggest that it disperses between most remaining forest ‘patches’ and that the population is not ‘fragmented’, nor in less than 10 locations, nor declining in number of locations or sub-populations.

    Based on the paucity of records, I would (be precautionary and) suggest that the population size may be 2500-10,000 individuals.

    The rate of decline would be similar to the rate of forest loss (but not forest degradation). The website suggests an annual forest loss of 0.24% across the Solomon Islands between 2000-2010. I know of no other threats to the species (unlike the otherwise similar Fearful Owl which is also hunted for meat).

  2. Joe Taylor says:

    The following comment was received from Jon Hornbuckle on 29 January 2011:

    Yes, only heard once when I spent 4 weeks birding on Solomons in 1999 and not at all on Bougainville in 2009

  3. Chris Gooddie says:

    A single individual was seen above Tirotonga, Santa Isabel 5th Oct 2009, approx. 20 mins. walk from the village. Photographs of this individual:

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