The rufous-backed dwarf kingfisher (Ceyx rufidorsa) is a small bird in the kingfisher family Alcedinidae that is found in parts of Maritime Southeast Asia. It was formerly considered to be conspecific with the black-backed dwarf kingfisher and together the two taxa were known by the English name "oriental dwarf kingfisher".
This tropical kingfisher is easily distinguishable from other birds in its range due to its red bill, yellow-orange underparts, lilac-rufous upperparts, and rufous back. It resides in lowland forests, typically near streams or ponds, where it feeds upon insects, spiders, worms, crabs, fish, frogs, and lizards.
The rufous-backed dwarf kingfisher was formerly considered to be a colour morph of the black-backed dwarf kingfisher (Ceyx erithaca). The two species complex was known as the "oriental dwarf kingfisher". Molecular genetic studies have shown that Ceyx rufidorsa is a distinct taxon and that the polymorphism is the result of ancient introgression in which some genes from Ceyx erithaca were transferred to Ceyx rufidorsa around 140,000 years ago.[4][5]
^Lim, H.C.; Sheldon, F.H.; Moyle, R.G. (2010). "Extensive color polymorphism in the southeast Asian oriental dwarf kingfisher Ceyx erithaca: a result of gene flow during population divergence?". Journal of Avian Biology. 41 (3): 305–318. doi:10.1111/j.1600-048X.2009.04913.x.
^Shakya, S.B.; Alexander, A.; Lim, H.C.; Manthey, J.D.; Prawiradilaga, D.; Chan, K.O.; Sheldon, F.H.; Moyle, R.G. (2023). "Demographic history of a complex polymorphism in populations of the Oriental Dwarf Kingfisher (Ceyx erithaca/rufidorsa) of Southeast Asia". Ibis. 165 (4): 1267–1279. doi:10.1111/ibi.13207.
