NT
Cordillera Ground-warbler Robsonius rabori



Justification

Justification of Red List category
This species is listed as Near Threatened due to its restricted range where there is an ongoing decline in habitat quality.

Population justification
The population size is unknown due to a lack of population size or density surveys throughout its range. It is described as 'scarce' (Allen 2020), but may be commoner than records suggest.

Trend justification

Analysis of land cover from 2011 to 2022 indicates a c.4% decrease in tree cover over the past three generations (Global Forest Watch (2024) based on data from Hansen et al. (2013) and methods therein). Declines are therefore tentatively suspected to fall within the band 1-9% in three generations. Deforestation primarily results from logging, agriculture and mining (Perez et al. 2020). Additionally, only a small portion of the species’ range falls within protected areas (<5%), thus declines are suspected to continue in the future.

Distribution and population

Robsonius rabori is found in northern Luzon, Philippines.

Ecology

This species is found in lowland forest and secondary growth from sea-level to 1,300 m. It may be more frequent in younger second growth, however this may be a function of suitable dense undergrowth (rather than preference for secondary habitats per se) which this species appears to prefer (Hosner et al. 2013). It presumably feeds on invertebrates, and has been observed walking across the forest floor searching for prey in the leaf litter, sometimes in pairs (del Hoyo et al. 2007, J. C. Gonzalez in litt. 2010). It is often encountered in the vicinity of small streams (D. Allen in litt. 2012). Very little is known about its breeding habitats. Its nest is a large dome made of dry sticks, branches and leaves (Sánchez-González et al. 2010).

Threats

The largest threat to R. rabori is habitat loss and degradation due to logging, agricultural expansion, mining and slash and burn farming practices. Remote sensing data indicate a c. 4% decrease in tree cover over the past three generations (Global Forest Watch (2024) based on data from Hansen et al. (2013) and methods therein). In Northern Luzon, communities engage in kaingin, a slash and burn farming method. Deforestation is often followed by the invasion of Imperata cylindrica, commonly known as cogon grass (Bensel and Kummer 1996). Allowing for a sufficient period of fallow can facilitate forest regeneration, however, if cogon takes over before this period, it renders the land "useless," a process seen in many parts of the Cagayan Valley (Bensel and Kummer 1996). Only a very small part of the species range, <5%, resides within any kind of protected area.

Conservation actions

Conservation Actions Underway
No targeted actions known.

Conservation Actions Proposed
Assess the population size and establish a monitoring programme to establish trends. Establish its ability to persist in degraded habitats. Identify and assess threats. Ensure that its remaining habitat is protected.

Identification

Acknowledgements

Text account compilers
Calvert, R., Chad, E., Martin, R., Allinson, T, Symes, A., Westrip, J.R.S., Taylor, J.

Contributors
Allen, D. & Gonzalez, J.C.


Recommended citation
BirdLife International (2024) Species factsheet: Cordillera Ground-warbler Robsonius rabori. Downloaded from https://datazone.birdlife.org/species/factsheet/cordillera-ground-warbler-robsonius-rabori on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 22/11/2024.