Reproductive ecology of the threatened great slaty woodpecker Mulleripicus pulverulentus

The Great Slaty Woodpecker Mulleripicus pulverulentus (GSWO), one of the world’s largest, occurs in mature broadleaved forests of south- and southeast Asia. Habitat loss, logging, and timber extraction has caused a drastic population decline, due to which it is listed 'vulnerable' by IUCN. Despite its threatened status, basic knowledge about its breeding biology is deficient. We studied the nesting ecology of the GSWO in the Himalayan foothill Sal Shorea robusta dominated dipterocarp forests of Uttarakhand, northwest India over four years (2016–2019). We searched for active GSWO nests and documented various aspects of nesting from cavity excavation to fledging. Data were collected using direct observations by observers, as well as by video footage of active nests by cavity cameras and time-lapse cameras. We observed 9 nesting instances from 5 nesting cavities. All cavities were excavated in live Sal trees of DBH 53–98 cm (mean 73.4 cm). Nest excavation took a minimum of 9 days. Clutch size was 4, wherein one egg was laid per day over 4 successive days. Incubation period was 12–13 days. The number of chicks successfully fledged was generally 2 (range 1–3). Fledging duration was 5–6 weeks. Cooperative breeding was confirmed at 6 out of 9 nests, with 1–3 regular helpers (accompanied by 1–2 additional individuals) assisting the active pair in care of the young. Care duties were primarily shared between male and female adults, with minor/passive contribution by helpers. We documented instances of reuse of nest cavities across years by GSWO. We recorded predation on GSWO chicks by Bengal Monitor Varanus bengalensis lizards and Yellow-throated Marten Martes flavigula. Breeding success was 67%. Information generated during our study about the breeding ecology of the GSWO contributes towards a better understanding of the species and will aid to guide conservation actions targeted at this threatened woodpecker.

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