- The charismatic Malabar gray hornbill is endemic to the Western Ghats and has a loud call that makes it easy to spot even from afar.
- The population of the bird, a keystone species in the Western Ghats, is declining.
- Conservationists say a decline in numbers could have an irreversible impact on the forest ecosystem in the long term, as the species plays an important role in the growth and survival of a forest.
Its loud call is distinctive. A series of yelps that almost sound like maniacal laughter as they reach a crescendo. It can be heard from afar, making the Malabar gray hornbill an easy-to-spot bird in the high, humid forests of the Western Ghats. Its large range, in which high densities have been recorded, meant that the species was not considered threatened with extinction.
But things have taken a turn in the past two years with research indicating a downward trend in the population of the Malabar gray hornbill (Ocyceros griseus). The IUCN Red List, which indicates the global extinction risk status of species, notes: “There is sufficient evidence to infer that there is a rapid and continuing population reduction throughout the range of distribution at a rate of 30 to 49% over three generations. It is believed that this will likely continue unless the critical factors causing the decline are identified and reversed.
The State of India’s Birds Report 2020 also provided evidence to suspect that there is a considerable decline in the population of the species.
The report indicates a “long-term” trend shows a decline of 66.8%. The long-term trend is the change in abundance index (reporting frequency) in 2014-2015 compared to before 2000. A value of -15% indicates that there has been a 15% decline in frequency of declarations during this period. The ‘current’ trend, meanwhile, shows a 3.3% reduction in numbers, respectively – indicating that there is an average annual decline of 3.3% in reporting frequency between 2014/15 and 2018/19, a period of 5 years.
Range-wide population trends generated from the citizen science portal, eBird, also tentatively place the rate of decline of the Malabar gray hornbill population in the 30-49% band over three generations. . The IUCN SSC Hornbill Specialist Group also raised concerns.
“The general population of the Malabar gray hornbill is in decline. Some outliers may indicate otherwise. You might even find them in good numbers in some areas and reserved forests, but overall their densities are decreasing,” says Anish Andheria, chairman of the Wildlife Conservation Trust.
The Malabar gray hornbill is endemic to the Western Ghats and associated hills of southern India and can be found from Nashik in Maharashtra to the southernmost hills. It prefers to inhabit moist evergreen and semi-evergreen forests in the tropics, but can also often be spotted in home gardens, timber plantations, and coffee and cardamom plantations that lie next to their preferred habitats.
Cavity-nesting, the breeding season of the Malabar gray hornbill extends from February to May, with the female selecting mature trees that have significantly large trunks (height 36 m +/- 6 m, circumference 3 m, +/ – 1 m) to nest. The nest must also be higher (17m, +/- 6m) to prevent predators from climbing it. A clutch of four eggs is laid. The incubation period is around 40 days and the young period is 46 days. The fruits of ficus, fishtail palms, etc. are usually eaten during the breeding and non-breeding season, but the species has been known to feed on snakes, lizards and small birds during the breeding season and when they have to feed their chicks,” says Vinod Karnik , an ecologist, who has been researching birds in the Western Ghats for more than a decade.
The Malabar gray hornbill is an indicator species and has long been praised by conservationists for the important role it plays in the forest ecosystem. It facilitates seed dispersal which helps the forest grow and thrive, thereby indirectly supporting the local wildlife population and reducing human-wildlife conflicts to a great extent.
“Some seeds only germinate when they pass through the gut of a bird or mammal. Since the Malabar gray hornbill is relatively large in size, it helps disperse larger seeds that smaller birds cannot consume. You may not notice an immediate impact in the forest, if their numbers dwindle. In the long term, however, there will be an irreversible impact on the ecosystem since some tree species will not be able to survive without them,” explains Andheria.
There are several threats to the Malabar gray hornbill population. Deforestation driven by agricultural conversion is believed to be one of the main reasons for the decline in their numbers. Another reason could be the unavailability of large trees suitable for nesting (the bird is unable to dig its own hollow and depends on natural hollows). “They need large, good-quality forests to thrive. You will find more hornbills in areas with less historical damage and where there is old growth forest. But while forest cover may have increased according to the State of the Forest Report 2021, forest quality has declined. Dense forests, for example, have become less dense,” says Andheria.
Forest fragmentation also affects the species. Potential threats could also come from an undocumented shift in the range of a competitor or predator, an undetected disease affecting individuals of that species or limiting resources, or an altered agricultural practices. “But more research is needed to confirm this,” says Karnik.
On January 10, 2020, based on research by Bird Life International, the International Union for Conservation of Nature revised the status of the Malabar Gray Hornbill to “Least Concern”, where the species is assessed with low risk from extinction to “Vulnerable”, which means that the species is threatened with global extinction.
But more needs to be done to ensure that the population does not decline further. A suggested step is to ensure compliance with forest protection regulations in protected areas, to avoid the loss of large trees with suitable cavities or large trees that will develop large cavities. “We also need more data to understand the reasons for their declining numbers and need to start thinking about creating artificial cavities and other ways to help give the species a helping hand to come back,” Karnik said.
The conservation of this key species of the Western Ghats is essential and must be given the attention it deserves. “Failure to save the Malabar gray hornbill could have a cascading effect on the forest and the wildlife that live there in the long term,” says Karnik.
Banner image: Malabar Gray Hornbill. Photo by Anish Andheria.