Javan Frogmouth (Batrachostomus javensis) [XC90730]
by Fabian Ducry & David Marques from Carita, West Java, Indonesia (song)
Javan Frogmouth (Batrachostomus javensis) [XC237109]
by Paulo Alves from Gede Pangrango National Park, West Java Province, Java, Indonesia (call)
Subspecies
Formerly considered conspecific with Sunda Frogmouth (Batrachostomus cornutus) by some, but a combined study of vocalizations and museum specimens in 1978 confirmed earlier suggestions that it should be regarded as a distinct species. Subspecies affinis sometimes considered a distinct species. Sometimes treated as conspecific with Hodgson's Frogmouth (Batrachostomus hodgsoni), but differences in bill size and structure, development of facial bristles, relative tail length and vocalizations, and also perhaps in bare-part colours (bill said to be often more straw-coloured), too great for them to be considered even as forming a superspecies. Subspecies continentalis is apparently connected to affinis by an intermediate population around Khao I Phrom in central peninsular Thailand. Birds from Palawan, Culion I and Banggi I often separated as subspecies chaseni, but appear inseparable from affinis.
A recent claim of a new species (Pygmy Frogmouth (Batrachostomus pygmaeus)) from Palawan (Basuanga I) seems unconvincing, the single specimen on which description is based being little different from local "chaseni" (= affinis).
The following 3 subspecies are recognised:
chaseni Stresemann, 1937 - Western Philippines (Culion I, in Calamian Group; Palawan) and Banggi I (off Northern Borneo). Considered by some authors to be a distinct species, Palawan Frogmouth (Batrachostomus chaseni).
pygmaeus Alviola, 1997 - Calamian Group (Busuanga I), north of Palawan, in Western Philippine Is. Considered by some authors to be a distinct species, Pygmy Frogmouth (Batrachostomus pygmaeus).
BirdLife International Species Factsheet