What Woodpeckers are Telling Us, and Why it’s Important

Woodpecker decline

Growing up in a city as green as Delhi in the 1980s, the yellow-crowned woodpecker was almost as common as the more flamboyant black-rumped flameback with its ringing call. I’d often spot the quiet, diminutive yellow-crowned woodpecker in parks, city forests, and tree-lined avenues. Over the years, birdwatchers began to notice that this bird was not as visible as before. Today, the yellow-crowned woodpecker is rarely seen in the city; it is occasionally recorded in larger scrub forest patches such as Asola Wildlife Sanctuary and the JNU Campus. The State of India’s Birds report (SoIB) 2023 confirmed this trend, showing that the woodpecker population had declined by roughly 70 per cent in just three decades. In the Handbook of Birds of India and Pakistan (1970 ). Ali and Ripley mention that the yellow-crowned woodpecker was “one of the commonest and most widely distributed of our woodpeckers”.

What could be the reason for the decline of this once-common bird? Perhaps its decline is linked to its preference for native scrub forests. This habitat has shrunk all over the country due to suburban sprawl and plantations, and the subsequent spread of the exotic vilayati kikar (Prosopis juliflora). In an article in Indian Birds, Sudhir Vyas , the eminent birdwatcher, mentions the preference of this species for native trees of the scrub forest, such as ronj (Acacia leucocephala) and babool trees (Acacia nilotica), which have been jostled out by vilayati kikar over the last few decades. Or could the answer lie in the burgeoning population of rose-ringed parakeets in urban areas? We can only speculate that in cities at least, the black-rumped flameback and the rose-ringed parakeet, being more aggressive and adaptable than the smaller, yellow-crowned woodpecker, compete with it for nesting cavities and foraging trees.

Several other woodpecker species mirror the declining trend in the yellow-crowned woodpecker, yet the reasons remain a mystery. Few other bird groups are so intimately dependent on forests as woodpeckers. Woodpeckers feed on insects from the bark and leaves of trees and make holes (cavities) for nesting. They need tall, old trees with lots of branches, in addition to standing dead trees, and plant cover where their insect prey can survive. Woodpeckers also need leafy cover for protection from eagles, crows, snakes, civets, and martens — predators constantly looking to snack on their nestlings. In short, woodpeckers thrive in tall, old forests with large-girthed trees of native species. Scientists believe that it is the loss and degradation of native forests that may have led to the decline of these birds.

Large woodpeckers are more vulnerable

Large woodpeckers need large areas of forest to survive, so forest continuity is critical. Fragmentation of forests due to infrastructure projects and agricultural fields affects larger species disproportionately. The observed decline of the white-bellied woodpecker (50 per cent over the last three decades, according to SoIB 2023), a denizen of old-growth rainforests and moist deciduous forests, is likely linked to fragmentation and shrinking of its forest habitat in the Western Ghats. Old-growth forests or primary forests contain trees that have grown over a long period without disturbance. The ornithologist V Santharam estimates that a single breeding pair requires as much as 500 hectares of forest, leading to an estimate of 1,000-1,500 sq km of forest for a viable population of 500 birds. Further, Santharam found nests only in trees with a girth of 185 cm and above, that too, largely in standing dead trees, rather than live ones. 

Not only do larger woodpecker species need larger trees (to be able to glean enough area of bark and branches), but they also need them to make the large cavities they need. It may not be a coincidence that the two woodpecker species that are now presumed extinct are large ones: the imperial woodpecker (Campephilus imperialis) from Central America and the ivory-billed woodpecker (Campephilus principalis) from the southern USA and Cuba. The largest living species today, the great slaty woodpecker (Mulleripicus pulverulentus), was also uplisted as “Vulnerable” on the IUCN’s Red List in 2010, based on a steep decline of 59-76 per cent over three generations. In India, this rare species is restricted to old-growth sal forests in the Himalayan foothills.

Small size doesn’t always help

Being small in size does not necessarily seem to guarantee survival either. At the other end of the size spectrum, the brown-capped pygmy woodpecker (Dendrocopus nanus) is one of the tiniest woodpeckers in the world at 13 cm. This is another species we don’t know enough about, although it is seen easily in dry deciduous forests in good condition. This species is also showing a sharp declining trend — roughly 50 per cent of its historical baseline (SoIB 2023). The species is rarely found feeding on tree trunks like other woodpeckers; rather, it feeds on slender branches and leafy tips of large trees (microhabitats at a premium in degraded forests).

Rare species go first

One can speculate that these woodpecker species represent the tip of the iceberg in terms of vulnerability. Only 11 of the 32 woodpecker species in India could be analysed for SoIB (2023) with enough data from eBird. The remaining 21 species are naturally rare or inhabit remote, under-explored places. Naturally rare species such as the rufous woodpecker (symbiotic with tree ants) or white-naped woodpeckers (specific to dry forests and edge habitats) could be less tolerant of land use change, but the numbers of these specialised birds are too few to analyse.  

Rare birds also include extreme forest specialists like the rufous-bellied woodpecker, a sap-sucking species restricted to mid-altitude (1,500-2,400 m) oak forests in the Himalayas. Within the site of our long-term study in Mukteshwar, Nainital District, these birds are recorded only in dense oak forests, where they have year-round access to sap trees of different species. The rufous-bellied woodpecker, predictably, is not found in fruit orchards or pine forests, where the tree canopy is open and there are very few trees to supply sap.

When can we call a forest a forest?

The slow decline of some woodpecker species in our forests could be connected to the status of forests, particularly the degree of degradation. Analysts believe that while green cover may be going up in the country, as suggested in the 2021 FSI report, a large part of this green cover might consist of monocultures of oil palm, coffee, rubber, city parks, and institutional forests. Even more alarming is that 95 per cent of the deforestation in the country might be occurring in natural forests rather than plantations or city forests, based on data from Global Forest Watch. There is also considerable visible evidence of degradation of forests across the country, signified by low numbers of tree species and poor structure (weak or imbalanced). 

Species losses from Indian forests raise relevant questions for conservation. Can we still call a forest a forest if some of its keystone species, like woodpeckers, disappear? It seems that we may have to redefine the term “forest” if such definitions are to guide conservation policies. For instance, Raman Kumar and associates (2011), working in the sal forests of Corbett Tiger Reserve, found that teak forests harboured only 5-6 species and worked sal forest (from where timber was extracted historically) supported 7-8 woodpecker species. The full complement of 10-11 woodpecker species of the area was recorded only in the old-growth sal forest in the core area of Corbett Tiger Reserve, which had been protected from logging for about 75 years.

The specific factors that trigger species loss from our forests are still to be uncovered. Without further research, we may never be able to explain why some species disappear. Being conspicuous, easy to identify, and good forest indicators, woodpeckers offer us an opportunity to better understand biodiversity loss in Indian forests and, more importantly, why this should matter for forest policy in the current times.

Photo sources: cover photo, white-naped woodpecker, Prosopis juliflora, Acacia leucophloea