Sierra Madre ground warbler

Sierra Madre ground warbler
Conservation status
Least Concern (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Passeriformes
Family:	Locustellidae
Genus:	Robsonius
Species:	R. thompsoni
Binomial name
Robsonius thompsoni Hosner et al., 2013

The Sierra Madre ground warbler (Robsonius thompsoni) is a species of passerine bird in the family Locustellidae. It is endemic the Philippines on the island of Luzon in its northeastern and eastern side by the foothills of Sierra Madre.Its habitat is in tropical moist lowland and the lower reaches of tropical montane Forest. It along with its closest relatives the Cordillera ground warbler and Bicol ground warbler are one of the most elusive birds in the country due to their extremely shy nature. While not officially threatened its populations are said to be declining to do habitat destruction through deforestation.

The Sierra Madre ground warbler feeds on insects and lives in tropical understories. It is a ground-walking songbird — rotund, with strong legs and weak wings — and it appears that it can barely fly. It tend to inhabit dense forest understories, where they feed on insects. The bird looks similar to the other two species of ground warblers on the island of Luzon, the Bicol ground warbler and the Cordillera ground warbler, and probably for this reason that it was not recognized as an separate species.^[2][3]

Description and Taxonomy[]

EBird describes the bird as "A medium-sized bird of the forest floor from the lowlands to low elevations in the mountains in northeastern Luzon. Fairly stout, with a pale lower bill, long legs, and large feet. Pale below, with a grayish, faintly scaled chest and brown under the base of the tail. Note rufous face and forehead with pale bare skin in front of the eye, brown upperparts with two dotted white wingbars, and chestnut flight feathers. Note the white throat with black speckling below and a thin black moustache stripe. Unmistakable. Song consists of a very high-pitched “tseeee-sip tsee-wee!”"^[4] Their song is extremely high in pitched and it is difficult to locate the source of the sound in the forest — they always sound like they are far away, even when they are almost at your feet. ^[2][3]

The three species of ground warblers are similar in size, shape and in the coloration of their juvenile plumage, but they differ from one another in their adult plumage coloration. Since they are so alike they were always thought to be the same species, until a DNA test was conducted proved they were multiple species^[5] It is differentiated from the Cordillera ground warbler and Bicol ground warbler with its ashy gray chest and spotted markings on its chin and neck. ^[6]

The species was first described by the ornithologists Peter Hosner and colleagues in 2013 and given the binomial name Robsonius thompsoni. The specific epithet was chosen to honour the ornithologist Max C. Thompson.^[7] This species is placed in the genus Robsonius that was introduced by the English ornithologist Nigel J. Collar in 2006.^[8]

Behaviour and ecology[]

It is a ground-walking songbird — rotund, with strong legs and weak wings — and it appears that it can barely fly.^[2][3]

Breeding[]

Very little is known about the Sierra Madre ground warblers breeding method. The nest are mostly found on rock cliffs, made up of wet sticks, branches, and leaves. The nest is a dome shape and has an entrance way in it. The dome is held up by twigs attached to the rock and mud that surrounds it.

Food and feeding[]

The diet of the Sierra Madre ground warbler is primarily invertebrates, it has been sighted scouring forest floors for prey hidden under leaves.

Habitat and Conservation Status[]

It is found in lowland moist and low montane dipterocarp forest in primary forest, secondary forest and forest edge up to 1,300 m. It is typically found on the forest floor among limestone outcrops, bamboo and mossy rocks. ^[6]

IUCN has assessed this bird as a Least-concern species The global population size has not been quantified, although it has been described as uncommon. However, it may be more common than suggested by field observations, owing to its secretive habits. Among the other Robsonius ground-warbles, the Sierra Madre ground warbler has the largest range.

Despite not being threatened, the Sierra Madre mountain range has experienced large amounts of deforestation that continues at present thus populations are declining. This species' main threat is habitat loss with wholesale clearance of forest habitats as a result of logging, agricultural conversion and mining activities occurring within the range.

It is found in two protected areas in Northern Sierra Madre Natural Park and the Aurora Memorial National Park however like most areas in the Philippines protection is lax.

Conservation actions proposed include to assess the population size and establish a monitoring programme to quantify trends. Establish its ability to persist in degraded habitats. Identify and assess threats. Ensure that the Northern Sierra Madre Natural Park and the Aurora Memorial National Park are more effectively protected.^[9]

References[]

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