Difference between Abbott's Babbler and Buff-breasted Babbler

The difference between the Abbott's Babbler and the Buff-breasted Babbler:

1/ Abbott's Babbler: grey face, grey-brown colors, grey lore

Undertail coverts and the feathers around the vent  have rich rufous or bright orange-brown color.

2/ Buff-breasted Babbler: brown face, brighter brown, brown lore.