THREATENED SPECIES SCIENTIFIC COMMITTEE Established under the Environment Protection and Biodiversity Conservation Act 1999
The Minister’s delegate approved this Conservation Advice 15/07/2016 . Following a taxonomic revision, the name in the EPBC Act list of threatened species was updated to Hypotaenidia philippensis andrewsi on 07/12/2016.
Conservation Advice Gallirallus philippensis andrewsi
Cocos buff-banded rail
Conservation Status Gallirallus philippensis andrewsi (Cocos buff-banded rail) is listed as Endangered under the Environment Protection and Biodiversity Conservation Act 1999 (Cwlth) (EPBC Act) effective from the 16 July 2000.
The species was eligible for listing under the EPBC Act at that time as, immediately prior to the commencement of the EPBC Act, it was listed as Endangered under Schedule 1 of the preceding Act the Endangered Species Protection Act 1992 (Cwlth).
The main factors impacting on the species that are considered to be the cause for its eligibility for listing in the Endangered category are its small population size.
Garnett et al., (2011) reviewed the conservation status of all Australian birds and the review of the Cocos buff-banded rail and considered it to be Vulnerable as there are thought to be between 250 and 1000 mature adults in the wild. The Threatened Species Scientific Committee is using the findings of Garnett et al., (2011) to consider whether reassessment of the conservation status of each of threatened birds listed under the EPBC Act is required.
Description
The Cocos buff-banded rail is a short billed rail, with a slight size difference between males and females. Both sexes have similar plumage with russet-flecked dusky crown, a light rust nape and dark grey-black feathers with a tinge of brown on the mantle, back and scapular (Reid 2000; Schodde & Tidemann 1986). The back is heavily spotted with white all the way down to, and including, the rump. Prominent white barring occurs on the dark grey-black tail (Reid 2000). Wings are dusky with broad rust-buff bars grading whiter. The face has a prominent white-grey eyebrow, a broad rust stripe through the eye to the nape and grey cheeks. The eye is red. The sides of the throat and neck are pale grey. Black and white bars cover the ventral surface broken at the breast centre by a wide vertical buff band. The bill is brown, and legs and feet are light brown. Immature birds are duller without russet on the hind neck or buff band on the breast, and the eye is brown. Downy young are sooty black (Schodde & Tidemann 1986).
Distribution The primary population of Cocos buff-banded rail, estimated at approximately 800 adults occurs on North Keeling Island, part of the Cocos Keeling Island chain (Garnett et al., 2011; Woinarski et al., 2016). Located in the Indian Ocean, the Cocos Keeling Islands are approximately 2900 km north-west of Perth, 975 km west-south-west of Christmas Island and 1000 km south-west of Java Head. They are an Australian Offshore Territory, comprising 27 separate islands, 26 in the Southern Atoll, and North Keeling Island, located 24km to the north.
A second population of Cocos buff-banded rail s was established in 2013 on Horsburgh Island in the southern part of the Cocos Keeling Island group. This population was established through a translocation program undertaken as part of the implementation of the ‘National Recovery Plan for the Buff Banded Rail (Cocos Keeling Islands) (Commonwealth of Australia 2005). In total, 39 rails were moved to this island from North Keeling in 2013. This population has subsequently grown to approximately 121 individuals, as of June 2015. Following the reintroduction to
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Horsburgh Island, rails have also been seen on the nearby West Island and Direction Island. These rails presumably dispersed from the Horsburgh Island population (Woinarski et al., 2016).
Relevant Biology/Ecology
The Cocos buff-banded rail uses a variety of habitats on the islands, including foraging along the lagoon on North Keeling; nesting in birdlime tree (Pisonia grandis) debris, grass tussocks or similar ground layer vegetation; the forks of birdlime trees; and the bases of coconut palms. Up to 40 birds at a time have been seen foraging on the lagoon shore on North Keeling, suggesting that this is preferred feeding habitat (Reid &Hill 2005). On West Island, rails have been seen feeding on the airstrip and sheltering in Scaevola taccada thickets. The rails are omnivorous, consuming mostly crustaceans, molluscs, worms and insects, but also plants, seeds, fruits, frogs, eggs, carrion and refuse (Stokes et al., 1984; Marchant &Higgins 1993; Reid 2000). A generation time of 3.4 years is derived from an age at first breeding of 1.0 years and an annual survival of adults of 58 percent, both extrapolated from mean values for Rallus spp (BirdLife International 2011).
Threats There are no current threats on North Keeling or Horsburgh Islands, as cats (Felis catus ) and rats (Rattus rattus ) are not present and the islands are unoccupied. Conversion of diverse Pisonia forests to coconut plantations, predation by feral cats, black rats and perhaps exploitation by people, are likely to have caused their extinction on the other islands in the southern islands of the Cocos Keeling Island group. The greatest threat now is the accidental introduction of feral predators to North Keeling and Horsburgh Island (Reid 2000; Commonwealth of Australia 2005; Director of National Parks 2015; Woinarski et al., 2016).
Table 1 – Threats impacting the Cocos buff-banded rail in approximate order of severity of risk, based on available evidence.
Threat factor Threat Evidence base type and status Invasive species Introduction of potential North Keeling and Horsburgh Islands are currently pest free. vertebrate The introduction of a vertebrate pest to these islands could pests to North have catastrophic consequences and lead to loss of an entire Keeling and sub-population. Horsburgh Islands (e.g., rats, cats)
Conservation Actions
Conservation and Management priorities • Continue to protect North Keeling Island, as outlined in the Pulu Keeling National Park Management Plan (Director of National Parks 2015). • Ensure Horsburgh Island is managed to conserve the Cocos buff-banded rail by keeping vertebrate pests from the island. • Encourage significant threat reduction on other islands in the Southern Atoll to provide additional habitat for dispersing Cocos buff-banded rails.
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Survey and Monitoring priorities • Continue to monitor and assess rates of recruitment and mortality of the North Keeling and Horsburgh Island populations.
Information and research priorities • Collate detailed information on level of existing threats on southern islands in order to help select possible sites for intensive management for colonisation or re-introduction of rails.
References cited in the advice
BirdLife International (2011). ‘Species factsheet: Gallirallus philippensis ’. Retrieved 17 January, 2011 from
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