The ground tit, Tibetan ground-tit or Hume's ground-tit (Pseudopodoces humilis) is a bird of the Tibetan plateau north of the Himalayas. The peculiar appearance confused ornithologists in the past who called it as Hume's groundpecker and still later as Hume's ground jay or Tibetan ground jay assuming that it belonged to the family Corvidae that includes the crows and jays. Although morphologically confusing, the species has since been identified using molecular sequence comparisons as being a member of the tit family (Paridae) and is the only species in the genus Pseudopodoces.[2] It is found in the Tibetan Plateau of China, India, Nepal & Bhutan.
Pseudopodoces is somewhat similar in appearance to the unrelated ground jays (Podoces) but much smaller – about the size of a house sparrow (Passer domesticus) – and lacks any conspicuous markings. More strongly however, it resembles a wheatear (Oenanthe) in habitus, but lacks black feathers and has a strong and slightly downcurved bill resembling that of a chough (Pyrrhocorax) in shape (though not in colour). Its soft, lax body plumage is extremely cryptic in its natural habitat. The underside is a greyish-fawn in colour, with a tawny hue. The upper parts are mostly a darker fawn-brown, with the central rectrices and the primary remiges a little darker still; the head is colored like the underside, with a darker cap and light nape patch, somewhat reminiscent of some tits and chickadees, especially those from the genera Parus sensu stricto and Periparus. The bill, legs and feet are black. Males and females look alike.[3][4]
The voice is described as a plaintive whistling, cheep-cheep-cheep-cheep and it also has a two syllable finch-like call.[5]
The ground tit was traditionally considered a relative of the ground jays (Podoces), based on its voice and habits. Its autapomorphies have certainly puzzled 20th century ornithologists, but due to its remote range and nondescript appearance, it was little studied and not suspected to be anything but an aberrant ground jay for more than 100 years after its description by Hume.[7] In 1978[8] and 1989[9] however, two studies of its anatomy determined that – although at that time unassignable to any family due to its peculiar adaptations, it appeared that it was not a corvid but a more advanced songbird of the infraorder today known as Passerida.[2]
From 2003 onwards, osteological, mtDNA and nDNA sequence and other biochemical data[10] has firmly allied it with the tits and chickadees (Paridae). In fact, genetic evidence suggests that it is a closer relative of the great tit and its relatives in the genus Parus sensu stricto than the chickadees and their relatives of the genus Poecile.[11]
It occurs across the Tibetan Plateau of China and the neighboring areas of western Sichuan and Gansu. The Tibetan ground-tit inhabits open alpine steppe and sometimes more arid regions with small scattered shrubs, rarely if ever occurring lower than 3,000 meters above sea level. It is not found anywhere where dense vegetation (especially trees) predominates. The flight of this bird is not strong and it flies low over the ground preferring to run or jump out of the way if approached which it does very quickly. It moves on the ground in unpredictable hops and bounces which can be quite long – jumps of three times the bird's length are achieved without assistance by the wings – rather than striding or running like Podoces ground jays. Observers have compared the sight of a Tibetan ground-tit moving along to a small greyish-brown rubber ball.[3]