Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-22T13:11:24.387Z Has data issue: false hasContentIssue false

Using playback to estimate the distribution and density of the world’s smallest flightless bird, the Inaccessible Island Rail Atlantisia rogersi

Published online by Cambridge University Press:  24 August 2020

BEN J. DILLEY*
Affiliation:
FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa.
GEORGE SWAIN
Affiliation:
Tristan Conservation Department, Edinburgh of the Seven Seas, Tristan da Cunha, United Kingdom.
JULIAN REPETTO
Affiliation:
Tristan Conservation Department, Edinburgh of the Seven Seas, Tristan da Cunha, United Kingdom.
PETER G. RYAN
Affiliation:
FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa.
*
Author for correspondence; email: [email protected]

Summary

The Inaccessible Island Rail Atlantisia rogersi, the world’s smallest extant flightless bird, is endemic to Inaccessible Island, a 14-km2 uninhabited island in the Tristan da Cunha archipelago, central South Atlantic Ocean. Rail populations are notoriously hard to survey and the rugged topography of Inaccessible Island makes a survey particularly challenging. Fortunately, Inaccessible Island Rails are very vocal, because their secretive behaviour means birds are hard to observe in the dense vegetation. We assessed the distribution of rails across Inaccessible Island using playbacks at 350 point-count sites in October–November 2018. Rail calls were heard at 98% of sites and we estimate the rail population to be in the order of 10,300 birds (95% CI 9,100–12,200), based on estimated rail densities in the six main habitats. Historic population estimates were reasonably crude and thus not suitable for inferring population trends, but the population appears to be stable and we recommend the species’ status remains as ‘Vulnerable’. The accidental introduction of alien mammals poses the greatest threat to the survival of the Inaccessible Island Rail and the removal of house mouse Mus musculus and ship rat Rattus rattus from neighbouring Tristan da Cunha Island would greatly reduce the risk of such a catastrophe.

Type
Research Article
Copyright
© The Author(s), 2020. Published by Cambridge University Press on behalf of BirdLife International

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bibby, C. J., Burgess, N. D. and Hill, D. A. (1992) Bird census techniques. London, UK: Academic Press.Google Scholar
BirdLife International (2019) Species factsheet: Atlantisia rogersi. Downloaded from www.birdlife.org (accessed on 16 September 2019).Google Scholar
Dinesen, L., Chamorro, A., Fjeldså, J. and Aucca, C. (2017) Distribution and habitat description of Junín Rail Laterallus tuerosi, Andean Peru. Bird Conserv. Internatn. 27: 388397.CrossRefGoogle Scholar
Elliott, H. F. I. (1957) A contribution to the ornithology of Tristan da Cunha group. Ibis 99: 545586.CrossRefGoogle Scholar
Evens, J. and Nur, N. (2002) California Black Rails in the San Francisco Bay region: spatial and temporal variation in distribution and abundance. Bird Populations 6: 112.Google Scholar
Fraser, M. W., Dean, W. R. J. and Best, I. C. (1992) Observations on the Inaccessible Island rail Atlantisia rogersi: the world’s smallest flightless bird. Bull. Brit. Ornithol. Club 112: 1222.Google Scholar
Hagen, Y. (1952) The birds of Tristan da Cunha. Results of the Norwegian expedition to Tristan da Cunha 1937–1938 20: 1248.Google Scholar
Lowe, P. R. (1923) Notes on some land birds of the Tristan da Cunha group collected by the ‘Quest’ Expedition. Ibis 65: 511528.CrossRefGoogle Scholar
Lowe, P. R. (1928) A description of Atlantisia rogersi, the diminutive and flightless rail of Inaccessible Island (Southern Atlantic), with some notes on flightless rails. Ibis 70: 99131.CrossRefGoogle Scholar
Olson, S. L. (1944) Evolution of the rails of the South Atlantic islands (Aves: Rallidae). Smithsonian Contributions to Zoology 152: 153.Google Scholar
R Core Team (2014) R: A language and environment for statistical computing. Version 3.1. Vienna, Austria: R Foundation for Statistical Computing. Retrieved from http://www.r-project.org.Google Scholar
Richardson, M. E. (1984) Aspects of the ornithology of the Tristan da Cunha group and Gough Island, 1972–1974. Cormorant 12: 123201.Google Scholar
Ryan, P. G. (2005) Inaccessible Island seabird monitoring manual. Sandy, Bedfordshire, UK: Royal Society for the Protection of Birds. (RSPB Research Report No. 16).Google Scholar
Ryan, P. G. (2007) Field guide to the animals and plants of Tristan da Cunha and Gough Island. Newbury, UK: Pisces Publications.Google Scholar
Ryan, P. G. and Glass, J. P. (2001) Inaccessible Island Nature Reserve Management Plan. Edinburgh, Tristan da Cunha: Government of Tristan da Cunha.Google Scholar
Ryan, P. G., Dilley, B. J. and Ronconi, R. A. (2019) Population trends of Spectacled Petrels Procellaria conspicillata and other seabirds at Inaccessible Island. Mar. Ornithol. 47: 257265.Google Scholar
Ryan, P. G., Watkins, B. P. and Siegfried, W. R. (1989) Morphometrics, metabolic rate and body temperature of the smallest flightless bird: the inaccessible island rail. Condor 91: 465467.CrossRefGoogle Scholar
Steadman, D. W. and Franklin, J. (2000) A preliminary survey of landbirds on Lakeba, Lau Group, Fiji. Emu 100: 227235.CrossRefGoogle Scholar
Stervander, M., Ryan P, G., Melo, M. and Hansson, B. (2019) The origin of the world’s smallest flightless bird, the Inaccessible Island Rail Atlantisia rogersi (Aves: Rallidae). Mol. Phylogenet. Evol. 130: 9298.CrossRefGoogle Scholar
Wace, N. M. and Holdgate, M. W. (1976) Man and nature in the Tristan da Cunha Islands. Morges, Switzerland: International Union for Conservation of Nature and Natural Resources. (IUCN Monograph No.6).Google Scholar