Coral-billed Ground-cuckoo is restricted to Thailand, Laos, Vietnam and Cambodia, where it inhabits lowland forest, scrub and second growth, to 900 m and exceptionally 1,500 m (Payne and de Juana 2018).
It is currently classified as Least Concern on the basis that it is not thought to approach the thresholds for listing in a threatened category under any of the Red List Criteria. However, sightings are seldom reported from anywhere outside of Khao Yai National Park (Thailand), and although its secretive ground-dwelling lifestyle makes it difficult to find and it may be under-recorded, it appears increasingly likely that it is genuinely very rare and decreasing. In particular, the potential threat from hunters using cable-snaring means that, although data are lacking, the species may well now qualify for a threatened category (J. W. Duckworth, S. Mahood and R. J. Timmins in litt. 2016, 2017, 2018).
It is extremely patchily distributed in northern Cambodia, based on the distribution of semi-evergreen forest (S. Mahood in litt. 2016). Snaring is not currently thought to be a major issue here but the total population must nevertheless be very small. In the south of the country in the Cardamom Mountains the status is uncertain. The amount of habitat remains large and must have held a large population of the ground-cuckoo, but snaring of animals such as civets and porcupines has apparently increased and may well now be affecting the species (S. Mahood in litt. 2016).
Its status in Laos and Vietnam is now thought to be very poor due to the impacts of industrial drift-fence cable snaring which has been in widespread use since the 1990s, and it has been suggested that rates of decline over the past three generations in those countries may have exceeded 80% (J. W. Duckworth in litt. 2016, 2018).
In Thailand the species continues to be regularly recorded within Khao Yai NP in the south of the country, but recent records from elsewhere in the country seem to be extremely sparse. The extent of cable-snaring in the country is unclear.
In addition to the threat from snaring, the species may also have been affected by the reduction in large mammal and primate populations, as it apparently forages in areas disturbed by these animals (S. Mahood in litt. 2016).
Assessment against Red List Criteria
Criterion A – It is extremely difficult to ascertain the likely population trend given the lack of data on the species and the uncertainty over the proportion of the population within the different range states. Although the impact of snaring in Laos and Vietnam may have driven declines of over 80% in three generations (13 years) in these countries, it is assumed that the rate of decline in Thailand is much lower, while the situation in Cambodia is unclear. It is possible that the overall rate of decline might lie within the range 30-49% in three generations (13 years), in which case the species would warrant listing as Vulnerable under criterion A2cd+3cd+4cd. If available evidence suggested the overall rate of decline could be as high as 50-79% in 13 years it would warrant listing as Endangered under the same criterion.
Criterion B – The species has an extent of occurrence (EOO) of 816,000 km2 as measured according to IUCN guidelines. Please note that this is the area of a minimum convex polygon around the known range, and does not equate to the extent of suitable habitat for the species. It therefore does not meet the threshold for listing as Vulnerable under criterion B1. The global area of occupancy (AOO) has not been calculated, but given the EOO, the AOO likely exceeds the threshold for Vulnerable under this criterion (2,000km2). Therefore, the species likely does not warrant listing as globally threatened under this criterion.
Criterion C – the global population size has not been estimated but it is possible that it is now approaches the thresholds for listing under this criterion.
It would warrant listing as Endangered under criterion C2a(i) if the total global population is estimated to number <2,500 mature individuals with ≤250 in each subpopulation, and an inferred continuing population decline.
It would warrant listing as Vulnerable under the same criterion if total population was <10,000 mature individuals with ≤1,000 in each subpopulation, and an inferred continuing population decline (or if the total population was <2,500 mature individuals with 250-1,000 in the largest subpopulation).
Criterion D – The range is too large, and the population is assumed to still be too large, to warrant listing this species as Vulnerable under this criterion.
Criterion E – To the best of our knowledge, no quantitative analysis of extinction risk has been conducted for this species. Therefore, it cannot be assessed against this criterion.
Therefore, in the absence of any further information Coral-billed Ground-cuckoo may warrant listing as globally Vulnerable or Endangered under criterion A2+3+4 and.or criterion C2a(i), depending on best estimates of the global population trend over a 13 year period, and its likely overall population size and subpopulation structure. Comments and further information on the potential population size and trend are welcomed.
Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of the species’ Red List status. Therefore, please make sure your comments are relevant to the information that is sought, or about the species’ Red List status.
Payne, R. & de Juana, E. (2018). Coral-billed Ground-cuckoo (Carpococcyx renauldi). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/54850 on 14 February 2018).