22 May, 2020
Human beings have always been fascinated by birds and for good reason. Be it due to the sheer variety of colours, shapes and sizes or their captivating songs. But little do we realise that birds are an integral part of the ecosystem where they play an important role in providing a wide range of ecosystem services. Since birds inhabit all habitats on earth, their mere presence/absence can indicate the health of any ecosystem.
Eurasian Nutcracker (Photo: Ritesh Sharma)
Birds play an important role in maintaining the diversity of flora and fauna because they occupy nearly all the trophic levels in the food chain from consumers to predators. For example, frugivorous or fruit-eating birds, such as blackbirds, act as consumers and influence the germination process of a seed. Their gastrointestinal acids soften the hard seed coat of some seeds, enhancing germination potential of the defecated seeds. The Eurasian Nutcracker promotes the regeneration of Oak trees owing to its habit of hiding their nuts and seeds at the base of the tree trunk in the soil and tree crevices, thus, providing us free tree regenerations.
Although the role of birds as pollinators (e.g. white-eye, sunbirds) and seed dispersers (e.g. barbets and parakeets) is well known, their role as biological control agents is equally important. They maintain the population levels of their prey. For example, as the insect group is the most abundant in the animal kingdom, their population is regulated by insectivorous birds like flycatchers and warblers, drongos, bee-eaters. A single bird feeding on hundreds of insects each day helps in controlling and maintaining a sustainable population level of insects.
Purple Sunbird (Photo: Jyoti Kashyap)
Alexandrine Parakeet (Photo: Jyoti Kashyap)
Grey-hooded Warbler (Photo: Jyoti Kashyap)
The next level of controlling population level is done by carnivorous birds that predate on animals such as rodents. The controlling of population level of rodents is best explained by feeding behaviour of the Barn Owl. When a Barn Owl has chicks (this period usually lasts for 45 days), it consumes 5-6 rats per night which effectively means, it kills around 270 rats during those 45 days. This makes the Barn Owl an effective biological controller and an invisible friend to the farmer. Another important service provided by birds is controlling the spread of contagious diseases which is done by scavenging birds. One well-documented example of scavenging birds comes from vultures.
Photo by Sean McGee on Unsplash
Himalayan Griffon Vulture (Photo: Ritesh Sharma)
Birds are known for their close affinity with their habitat in which they are very prominent and easy to observe. They have a very rapid metabolism and occupy a high position in the food chain making them very sensitive to the smallest changes in a predictable manner in their habitats. Any change in their species composition and numbers indicates that their habitat or ecosystem is facing some problem. Due to their ability to fly away, they disappear from the affected area. But they are also the first to return and re-establish once the habitat is restored, thus indicating the effectiveness and success of the undertaken conservation measures and management actions. This makes them true indicators of the status of the environment.
Western Tragopan (Photo: Dr. K. Ramesh)
Among birds, there are generalist species, which have a broad survival ability, live in a wide variety of habitats, exploit diverse food items and exist in good numbers, and habitat specialists, which have very specific habitats and food preferences and exist in limited numbers. Abundance and assemblage of both types of species are potential indicators of the quality of an ecosystem and habitat. Usually, when the ecosystem changes from undisturbed to degraded, the specialist will disappear because the habitat becomes unsuitable for them. This dynamic is visible when a dense forest is converted into an open forest. There will be a change in species composition from the species preferring dense forest to species adapted to open forest. Consequently, every specific habitat has at least one species that indicates its presence. For example, Western Tragopan indicates the presence of dense coniferous and broad-leaf forest while White-browed Shortwing indicates the presence of subtropical or tropical moist montane forests. Some birds indicate the presence of freshwater such as Brown dipper, which is usually found in the flowing mountain streams and rivers in the medium to low elevations and Spotted Forktail which is restricted to well-shaded forest streams and creeks, particularly in rocky areas. The abundance and disappearance of these species from their habitats indicate a change in the forest. This is significant because the forest is an important source of water for the local communities.
Apart from indicating the health of any ecosystem, some birds indicate the availability of other bird species. Primary hole nesters such as woodpeckers and barbets are the birds which make holes in the tree for nesting. On the other hand, secondary hole nesters are the birds that depend on the primary hole nester because they occupy holes made by the latter. This means that if the primary hole nesters disappear from the forest habitat, the diversity of secondary hole nesters would also reduce. Absence of both indicates the presence of small-size trees, the absence of mature trees or a very young forest with more immature trees.
Great Barbet, a Primary Hole Nester (Photo: Jyoti Kashyap)
Russet Sparrow, a Secondary Hole Nester (Photo: Jyoti Kashyap)
Jacobin Cuckoo (Photo: Jyoti Kashyap)
Birds are also an important part of human culture and folklore. Some communities associate certain species of birds with the arrival of seasons. For example, displaying of male bird and nesting of birds indicates the advent of summer, return migration of winter visitors, the flowering of trees or in the case of Jacobin Cuckoo, the arrival of monsoons.
Keeping these integral ecosystem services in mind and the clear role of birds in improving biodiversity, the Himachal Pradesh Forest Department (HPFD) and the Himachal Pradesh Forest Ecosystem Services Project (HP-FES) identified birdwatching as a tourism product in one of the project demonstration site, Shangarh, under the ecologically sensitive tourism model. Shangarh lies in ecozone of Ropa range of Great Himalayan National Park, a World Natural Heritage Site. The HP-FES project is organising three-step birdwatching guide training for selected 20-30 rural youth of Shangarh. This training aims to develop their skills and capacity to offer the birdwatching services to focused clients and earn a livelihood. It will also enhance their contribution to conservation through birdwatching. Participants will be trained on bird ecology, identification, threats birds face as well as their recording and monitoring. The second component of the training will advance their conceptual knowledge on developing service packages in an ecologically sensitive manner. The training will be delivered by Dr. Justus Joshua from Green Future Foundation (GFF) and HP Forest Department official, Ms. Suvina Thakur. Successful channelisation of the training will strengthen the role of youth in conservation and help to develop an avifaunal database which supports in monitoring as well as management of the habitats in the line of Protected Area management approach.
Photo: Ritesh Sharma
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