This species has been split by Rasmussen and Anderton (2005) from the chestnut-bellied nuthatch. The Indian nuthatch (including the older prateri of the Eastern Ghats) is found South of the Ganges river. It is the only grey-backed, rufous-bellied nuthatch in the peninsula. Similar to the next but has a smaller bill and a frosty crown that is paler than the mantle. The wing and tail patterns lack contrast and has grey centres to the chestnut undertail coverts. Resident in the Terai and Gangetic plain extending into Central India, the Eastern Ghats, Sunderbans and a disjunct population in the Western Ghats. Breeds from February to July. Different in vocalization from the next.
- BirdLife International (2016). "Sitta castanea". IUCN Red List of Threatened Species. IUCN. 2016: e.T103880076A94281309. Retrieved 20 April 2017.
- J, Praveen (17 November 2015). "A checklist of birds of Kerala, India". Journal of Threatened Taxa. 7 (13): 7983–8009. doi:10.11609/JoTT.2001.7.13.7983-8009.
- "eBird India- Kerala". eBird.org. Cornell Lab of Ornithology. Retrieved 1 October 2017.
- K. K., Neelakantan (2017). Keralathile Pakshikal (Birds of Kerala) (5 ed.). Kerala Sahitya Akademi. p. 511. ISBN 978-81-7690-251-9.
- Grimmett, Richard; Inskipp, Tim; P.O., Nameer (2007). Birds of Southern India [Thekke Indiayile Pakshikal (Malayalam version)]. Mumbai: BNHS.
- Rasmussen, P. C. & J. Anderton (2005) The Birds of South Asia:The Ripley Guide. Smithsonian Institution and Lynx Edicions.