Assessing woodpeckers as indicators of bird diversity and habitat structure in managed forests

Woodpeckers (family Picidae) are a specialised group of insectivores that are sensitive to forest degradation and fragmentation. We evaluated the woodpecker taxa as potential indicators of habitat quality and forest bird diversity in temperate moist hardwood forests (1500–2400 m asl), a threatened biome in the Western Himalaya. 74 forest sites, selected to represent a gradient of anthropogenic use, were surveyed for birds, vegetation structure and proportion of land under dense forest in the surrounding landscape. Individual woodpecker species were observed to quantify their foraging niche preferences. We found that forest sites with higher woodpecker richness were also rich in all other bird species. Further, the richness and abundance of woodpeckers and all other birds were affected by similar habitat variables. Four out of the eight woodpecker species occurring in the study area were found to fit our habitat models suitably, with canopy cover, tree density, and forest proportion proving to be important variables. Behavioural observations showed that the same four woodpecker species significantly preferred larger and taller trees for foraging. Given the difficulty of directly monitoring forest characteristics and total bird diversity over large landscapes, consistent monitoring of sensitive woodpecker species can provide answers to both. Further, as woodpeckers are moderately common and conspicuous birds, areas with high woodpecker diversity can be easily identified and prioritised for conservation.