Bernieridae – Malagasy Warblers

The Bernieridae (Malagasy Warblers) are a newly validated (2017) family of passerines. They currently consist of eleven species (in eight genera) of small forest birds, which are all endemic to Madagascar.

The monophyly of this group has been proposed as early as 1934 (Salomonsen 1934). But the traditional assignments of these birds were maintained, mistaken by their convergent evolution and the lack of dedicated research. The families to which the Malagasy warblers were variously, formerly assigned – Pycnonotidae (bulbuls) but especially Timaliidae (Old World babblers) and the Sylviidae (Old-World Warblers) – were used as ‘wastebin taxa’, uniting unrelated lineages that were somewhat similar ecologically and morphologically. Much remains to be resolved to know exactly the relationship of this group, which closest relatives may be the African warblers of genus Cisticola that includes very small insect-eaters and was formerly part of the family Sylviidae.

Several of these species are very poorly known and were described by science only very recently. Appert’s Tetraka was only described in 1972 and the Cryptic Warbler in 1996. The Appert’s Tetraka, along with the Dusky Tetraka are threatened by habitat loss, and are listed as vulnerable.

The Malagasy warblers usually have dull colours, often olive-green, brownish or greyish above and yellow to whitish below, with sometimes contrasting head pattern such as pale supercilium, dark eye stripe or white throat. The more terrestrial species have strong legs and feet, and the bill is usually pointed, but there are many variations in bill shapes, size of wing and tail, and tarsus lengths. The Long-billed Bernieria, for example, has relatively long bill. Male and female have similar plumage and the juveniles are duller than adults. Some members of this family are more boldly patterned, longer-billed, or longer-tailed than is typical for the leaf or reed warblers that they most resemble.

Appert’s Tetraka Xanthomixis apperti

White-throated Oxylabes Oxylabes madagascariensis

They have short wings and some of them have fairly long, graduated tail, involving only short-distance, weak flights. They are not able to perform sustained flights and are sedentary on Madagascar.

Most live in the humid rainforests in the east of Madagascar, though a few species are found in the drier south west of the island at middle or high elevation. They forage, feed and nest in this habitat, and their morphology, plumage colour, legs, feet and bill shape are adapted to this environment. However, the Thamnornis is found in the spiny subdesert scrub and the scrubby edges of the western deciduous forest in the sub-arid region of south and west coast, whereas the Appert’s Tetraka frequents the dry deciduous forests and montane evergreen forest in southwest Madagascar.

Madagascar Yellowbrow Crossleyia xanthophrys

Wedge-tailed Jery Hartertula flavoviridis

They feed primarily on insects and spiders caught on the ground, in low vegetation, in tree canopy or at treetops by walking, hopping, climbing, gleaning and probing. They will form mixed-species feeding flocks of up to six species while foraging. They are very active, searching for prey in moss, epiphytic plants, leaf-litter, palm fronds, bark, sometimes hanging with fluttering wings, or working in tit-like fashion. They may perform short flights to pursue a flying insect or when foraging from tree to tree.