Family Grasshopper-warblers and Grassbirds (Locustellidae)

Least Concern

Sierra Madre Ground-warbler (Robsonius thompsoni)


French: Robsonie de Thompson German: Sierra-Madre-Grundsänger Spanish: Ratina de Sierra Madre

Robsonius thompsoni

Hosner et al.

, 2013,

12 km SW Baler, San Luis Municipality, Aurora Province, Luzon Island, Philippines (15°40’48” N, 121°31’44” E, elevation 525 m)


Species named recently in unusual circumstances: R. rabori was described from a juvenile in Cordillera Central of NW Luzon, and adults from Sierra Madre in NE Luzon were assumed to represent the same species#R; in fact, R. rabori proved to be distinct enough in adult plumage to represent a separate species (which see, for diagnosis), leaving Sierra Madre birds in need of a name. Monotypic.


N Sierra Madre in Cagayan, Isabela, Aurora and Nueva Vizcaya Provinces (NE Luzon, N Philippines)#R.

Descriptive notes

20–22 cm; 52·5–65 g. Crown and nape amber, feathers tipped dusky brown; ear-coverts amber and lores white, the feathers tipped black; small area of bare gray skin behind eye... read more


Song a variable, extremely high, wispy, slurred, insect-like “tsui-ts’siiuu’ee” or “tsui-ts’ssuu’ee... read more


Broadleaved lowland and lower montane forest, including primary forest, secondary forest, forest... read more

Food and feeding

Virtually no information on diet, but stomach contents of specimens included insect parts. Walks slowly across forest floor; also hops, and... read more


Fledglings reported in Feb, Mar, Apr, Jul and Aug. A nest found in mid Jun had a single egg, although the female was collected and another... read more



Status and conservation

Not globally threatened (Least Concern). Restricted-range species: present in Luzon EBA. Overall range estimated at 33,100 km², but population unknown. Status difficult to... read more

Recommended citation

del Hoyo, J., Collar, N. & Kirwan, G.M. (2019). Sierra Madre Ground-warbler (Robsonius thompsoni). 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 on 23 April 2019).