According to recent findings, it is most closely related to the Central Asian ground jays (Ericson et al., 2005).

DNA-sequencing analysis supports its placement in the corvids, with its closest relatives being the ground jays, magpies, and the Piapiac.

The ground jays or ground choughs belong to a distinct group of the passerine order of birds in the genus Podoces of the crow family Corvidae.

Ground jays show adaptations to ground living such as long, strong legs adapted to fast running and the ability to leap and bound onto boulders and rocks with great agility.

P. humilis is somewhat similar to the unrelated ground jays (Podoces) but much smaller - about the size of a House Sparrow (Passer domesticus) - and lacks any conspicuous markings.

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.

Rather, they can be divided into an American and an Old World lineage (the latter including the ground jays and the Piapiac), while the gray jays of the genus Perisoreus form a group of their own.

Henderson's Ground Jay (Podoces hendersoni)

Biddulph's Ground Jay (Podoces biddulphi)

Pleske's Ground Jay (Podoces pleskei)

Pander's Ground Jay (Podoces panderi)

The ground jays or ground choughs belong to a distinct group of the passerine order of birds in the genus Podoces of the crow family Corvidae.

The Henderson's Ground Jay or Mongolian Ground Jay (Podoces hendersoni) is a species of bird in the Corvidae family.

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.

During this journey, Biddulph collected numerous specimens of birds and mammals, including an unknown species of Podoces which was later named in is honour by Allan Octavian Hume as Podoces biddulphi.