Sikkim Wedge-billed Babbler or Blackish-breasted Babbler is one of the most wanted species of the birdwatchers in Eaglenest. It is a very restricted range species of the humid mid-montane forested zones of the East Himalaya. It is found from Bhutan, into the East of Arunachal Pradesh. More to the East and South, the Cachar Wedge-billed Wren-babbler or Chevron-breasted Babbler is found in the forested mountain ranges of East Arunachal Pradesh, Nagaland and Burma. Once considered as one species, the 'Wedge-billed Wren-babbler' was recently split into two species on the grounds of the distinctive voices and several distinctive plumage features. The habitat of the Sikkim Wedge-billed Wren-babbler consists of broadleaved evergreen forest, at an altitude between 1200 metres and 2000 metres above sea-level. Within this forested habitat it shows a preference for thick wet secundary growth and humid bamboo areas. Within a primary forest vegetation, such as much of the vegetation in Eaglenest, it is often found in humid gullies and wet places where treefall has been followed by the devolpment of thick and dense secundary growth. As the sepcies is an extreme skulker, spending most of his time in the dense and dark undergrowth, the best chance to find the species is by hearing it's song. The species is everywhere scarce to rare within it's range, so we were very glad to find the bird on our second day in Sessni, when he started singing low in a gully.

The 'Wedge-billed Wren-babbler' has recently undergone some taxonomic changes: previously the species was considered as a Wren-babbler species. Then the species was split into an Eastern and a Western race. Nowadays both species (Chevron-breasted Babbler and Blackish-breasted Babbler) have been classified as babblers, closely related to wren-babblers.