The Mysterious Bird—Rufous-Bellied Niltava

Rufous-bellied niltava, Niltava sundara, Hodgson, 1837, also known as the black-and-orange niltava or as the blue-and-orange niltava or orange-bellied niltava, also (appropriately) as the beautiful niltava, or as the Sundara/Sundra niltava, photographed at the Ban Luang Resort, Doi Ang Khang, Chiang Mai province in the far north of Thailand. This mystery bird is from Thailand.

This species is very similar to the small niltava, N. macgrigoriae, with nearly identical colouring and patterning of the upperparts, but the male rufous-bellied niltava is considerably, and has orange underparts (small niltava has grey-blue underparts).

The rufous-bellied niltava lives in the brushy undergrowth in a variety of moist and tropical forest types, including mixed, broadleafed, secondary and disturbed lowland montane forests throughout the Himalayas. The bird ranges from central China through Myanmar (Burma) and into northern Thailand and Indochina.

The rufous-bellied niltava, Niltava sundara, is a bird that perfectly demonstrates the power of complementary colors.

As typical for its family, this species is mainly insectivorous and it also consumes fruit. This species constructs an open cup nest hidden in dense vegetation. The hen lays 3-4 eggs per clutch, which she incubates alone, and both parents feed and care for the chicks. Young birds are primarily fed insects.

The male gets his brilliant colouring from a combination of pigments and structural colours. The orange underparts come from pigment-based colouring, created by a group of pigments known as carotenoids. The carotenoids are produced by plants, and are acquired by eating plants and storing the pigments until moult, at which time the carotenoids are placed inside the growing feathers.

These beauties’ habitat extends in a curve across southern Asia.

It starts in north-most Pakistan and skims the top of India before curving through mountainous Nepal, Bhutan, and down into the area of Myanmar, Thailand, and Laos. They can also be found in pockets throughout southeastern China.

Here is a video of an adult male:

Blue is a combination of structural colouring and pigment-based colouring. The rich dark blue of the bird’s upperparts is the result of tiny air pockets inside the feather barbs that scatter incoming light, creating the blue colouring. The feather itself contains pigments — melanins — that strengthen the feather structure and deepen the blue colouring. When you see this bird in low light or when it is backlit, the blue colouring resulting from light scattering is lost, so the bird will look black-and-orange instead of blue-and-orange.

This species is strongly dimorphic. The female has olive-brown upperparts, greyer crown and nape, a buffy eyering around large black eyes, rufous wings with white streaking, rufous tail. The underparts are greyish-olive, the throat is buffy and there is a small but very noticeable incomplete white neck band in the middle of the neck with a tiny iridescent blue at each end.

Here’s a video of an adult female:

They like brushy undergrowth in moist or tropical forests and eat mostly insects and fruit.

The particularly shiny nature of the males’ blue hues are due to a mix of dark melanin pigment and light scattering.


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