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Silencing The Chirps

TreeTake is a monthly bilingual colour magazine on environment that is fully committed to serving Mother Nature with well researched, interactive and engaging articles and lots of interesting info.

Silencing The Chirps

Silencing The Chirps

Silencing The Chirps

Chopping-off trees, filling-up of natural water bodies, shifting agricultural practices, mining, mindless construction and vehicular movement in the name of urbanisation is killing our birds- both native & migratory. And, the pace at which this is happening is alarming...

Himanshi Shukla

The Slender Billed Gulls are seabirds or wetland birds mostly in the Western Indian Ocean States and Islands. Interestingly, the bird creates its nest on land. On March 28, 2021, a bulldozer commissioned in for highway construction, destroyed 500 nests of the species!

It was October 2020 when the migratory birds in US state of Philadelphia flapped their wings to migrate towards warmer weather, following their usual North-South path in the eastern United States, known as the Atlantic Flyway. But behold, their flight was interrupted by the artificial lights of Philadelphia’s downtown skyscrapers. The bird species - mostly the Black-Throated Blue Warbler, the Common Yellowthroat and the Ovenbird were amongst some thousand birds that became disoriented and either died or were reported injured. The birds are especially drawn towards lighting during inclement weather. The windows of the skyrise buildings too pose a threat as the birds might see a reflection of trees or sky and assume the reflection as reality. Sadly, these aren’t the first (and who dare say the last) incidents where other living creatures, in this case the birds, are negatively impacted by the blinded race that isurbanisation.As per the State of India’s Birds Report 2020, “urbanisation is the biggest culprit behind avian decline.”

How does urbanisation impact the avifauna?

Wild-lifer and ex-member, Wildlife Board, Uttarakhand, Kaushalendra Singh says: “If urbanization means chopping-off trees, filling-up natural water bodies, mindless construction and vehicular movement leading to pollution, then it definitely affects not just birds but the biodiversity of a place.”  “As far as impact of urbanisation on birds is concerned, we need not go far,” he says while commenting on Urbanisation in Lucknow. “If we look at enormous construction activity going on at shaheed path we will get all the answers:

1. Construction of Ekana stadium by filling up of a big wetland and razing of a natural acacia jungle is a big setback, it was home to micro-organisms, reptiles, birds and small animals, local eco system has been shattered beyond repair.

2. Little ahead of the stadium Awadh Shilp gram was constructed after filling up 2 natural bodies which had lot of aquatic life which supported many bird species.

3. Even now some construction is going on after filling up water bodies adjacent to river Gomti which will displace many bird species.

4. Large scale construction continues behind Ekana stadium is not only converting wetland into a concrete jungle but is already in the process of displacing lot of bird species.

5. I am witness to displacement of several pairs of sarus cranes from shaheed path area, while the construction advanced; they kept on moving and finally vanished, possibly wherever they went must have faced same concrete vastness.

Industries small, big and cottage throw out toxic chemicals in the drains on which birds depend,” he points out.

Approximately, over half of humanity lives in the cities. Cities are typically characterised by dense habitations in resource rich regions. Consequently, the native fauna experience habitat loss, adaptive challenges and unlike us humans the birds cannot acclimatise to city life. Cities are novel ecosystems that are characterized by fragmented and disturbed environments. There are high densities of fabricated structures and impervious surfaces with strong heat-retaining abilities. This typically gives rise to the Heat Island effect which aids in successfully driving out the avifauna and in some cases is even fatal to them.  Incidents like Philadelphia (and many others which we will subsequently explore in this article) point to the degree of callousness in urban planning where there is complete disregard for other organisms that inhabit the earth. In other words, urbanisation is so designed that it only caters to our needs.

Nowadays, agricultural practices have totally changed. India is the world’s largest user of chemical pesticides and fertilizers. This intensification in agriculture has led to serious decline in a number of farmland birds and the house sparrow is no exception. The change in cropping patterns and introduction of exotic crops has also led to a decrease in food and large-scale habitat destruction. Many species have become extinct through human activities like excessive hunting, logging, large-scale use of insecticides and pesticides in agriculture and industrial pollution. Two birds that have become extinct in India are Mountain Quail and the Pink-Headed Duck.

Numerous species have come to depend on human activities for food and have adapted well to the rapid urbanization and growth in human population. For example, the House Crow and Rock Pigeon thrive near human habitation in large parts of the world. While in addition to these two species, the Common Myna, Bank Myna and Black Kite are thriving in India; Vultures (Aegypinae) and the House Crow are facing an inexplicable decline in their population.

The staggering numbers- According to Birdlife International, a total of 182 bird species are believed to have become extinct since the year 1500. Nineteen species have been lost in the last quarter of the 20th century, and four more are known or presumed to have become extinct since 2000. As of 2018, 1,630 (13%) species of birds are categorized as Threatened at different levels, and another 1,017 species are categorised as Near Threatened. India has 97 species under the Threatened category, a significant increase from 78 species two decades ago. This list adds up to 178 if Near Threatened species are considered.And among the Threatened species, 17 are Critically Endangered, which includes the Great Indian Bustard, Bengal Florican, the three resident species of Gyps vultures, and those that are most probably already extinct.

One of the most intriguing aspects of bird biology is the ability to migrate exceptional distances. Birds possess highly specialized directional senses for orientation, navigation, homing and migration, including the ability to detect the Earth's magnetic field. These uncanny abilities permit birds to occupy distinctive wintering and nesting grounds, thus expanding their usable habitats. Some migrations, such as that of the Arctic tern, involve a Circum-Atlantic migration from Alaska to the South Pole. There are some 9700 species of birds living today; some 5000 species belong to the order Passeriformes, the perching birds or songbirds. The number of avian orders is still controversial and texts show different arrangements. The avifauna of India includes around 1301 species, of which 42 are endemic and 26 are rare or accidental. 82 species are globally threatened. The Indian Peacock (Pavocristatus) is the national bird of India, with almost 150 species having become extinct after the arrival of humans.

Birds are highly visible and sensitive to alterations in habitat structure and function. Consequently, they serve as excellent indicators of changes and stresses in urban ecosystems. Several studies have examined the influences of urbanization on bird communities. (Mills et al., 1989; Jokimäki and Huhta, 2000; Cam et al., 2000) concluded that bird species richness, abundance and community structure are indeed affected by urbanization. The concept of an urban gradient of highly developed urban centres to less developed surrounding areas, McDonnell et al., (1993) and Blair, (1996) has shown that low levels of development can actually promote species richness by increasing resources such as food availability and shelter, in the forms of ornamental vegetation, nest boxes and bird feeders. Areas of intense urbanization often result in communities dominated by a few species.

Not the only case

Unfortunately, these aren’t just isolated case of birds being negatively impacted by Urbanisation. Closer home in Rajasthan, we have the example of threats faced by the already endangered Great Indian Bustard and the Lesser Florican. The Great Indian Bustard which was once seen very commonly at the dry plains of the Indian Subcontinent has now been pushed to extinction. Reportedly, only 130 birds in India were there in 2019, as per the Wildlife Institute of India, which was down from 250 in 2011. As per the Wildlife Institute of India, the Great Indian Bustard had faced a whopping 75% reduction in population in the last 30 years. Besides being critically endangered by hunting and loss of habitat, that is, dry grasslands and scrub, one major challenge that the bustard faces are electrocution by high tension electrical wires and collision into wind mills. As reported by the Wildlife Institute of India, the bustard is dying at an annual rate of 15% due to collision with electrical wires. The bird has a weak frontal vision due to which it is unable to foresee electric wires. Since it is of heavy build, it means it cannot fly higher than usual.

“The males are especially large and majestic, and males holding territories make a grandiose display, giving out booming calls that reverberate across the landscape. Being an open grassland species, the GIB (and probably all grassland wildlife species like the Bengal Florican and the Lesser Florican) benefited from the early activities of humans, such as the clearing of forests and rise of subsistence agriculture, aided by low livestockgrazing pressure in the cleared areas. Apart from the threat of predators, occasional hunting for the pot by local trappers was probably the only other danger it faced in early times. (However, there is a reference to the savouries of its flesh in the memoirs of the Mughal emperor Babar, which suggests that it could have been a targeted species.) Things changed with the arrival of the Europeans, guns, and later jeeps, especially for those who considered hunting a sport. One of the most despicable reports of hunting of GIB was in the defunct Oriental Sporting Magazine, where a writer signing himself as ‘Lover of all Sports’ claimed to have killed not less than 961 GIB from 1809 to 1929 in the neighbourhood of Ahmednagar in Maharashtra! Unforeseen issues like proliferation of power lines and windmills throughout the habitats of the species, ire of locals against the established sanctuaries due to crop depredation by Blackbuck that increased dramatically in numbers, loss of grazing lands, restrictions on right of way and developmental activities in the adjoining areas, ‘encroachment’ of remote areas by ever expanding cities and towns, and intensification and modernization of agriculture are some of the reasons for the rapid decline of the GIB,” says Associate Officer (Programmes) at the Bombay Natural History Society, Asif Khan.

Another dramatic decline among Indian birds is the case of three resident species of Gyps vultures. The loss of the Gyps species of vultures is attributed to the painkiller drug diclofenac used to treat sick cattle. Vultures die with time, on eating carcasses treated with diclofenac. Diclofenac was duly banned by the Indian Government for veterinary use and replaced by drugs safe for vultures in 2006 when advocated by birdwatchers. However, diclofenac continues to be used on the sly, there are other drugs that are toxic for vultures in the market. “New conservation issues may arise, and well-founded questions arise on the availability of safe areas with optimal food resources for vultures in the future in a developing/developed India with a billion plus human population,” says Dr Ranjit Manakadan, Deputy Director, Ornithology, Bombay Natural History Society.

The classic case of Sparrow

As per Asif Khan: “Even common bird species that have benefited from association with humans in towns and cities in India are disappearing, e.g., the House Sparrow. The loss of open spaces in cities and towns, with the increase in human population and urbanization, advent of box-like architecture that does not provide nesting niches for them, concretization of pathways and compounds, the spread of supermarkets and their like where grain comes packed in plastic (thus cutting out food sources once available), and insecticide-laden pests thrown out into the open from homes have all rung the death knell for sparrows.”

“Along with the sparrow, our rapidly changing rural and urban landscapes are seeing declines in species of prinias, bulbuls, orioles, mynahs, sunbirds, tailorbirds, babblers, and treepies. Only crows, koels, pigeons, and kites seem to be holding on in human habitation areas … but for how long?” he asks.

Modern house construction has meant that house sparrows struggle to find adequate nesting sites in today’s matchbox shaped houses. This buildings and houses have glass or Aluminium composite exterior of walls, which offer no place for nesting. The growth of cities and the increase in real estate prices have lead to destruction of old house and new modern building are constructed in their places. All these changes have resulted in lack of nesting sites for our winged friends.

The advent of cell phones has resulted in the proliferation of cell phone towers in the urban landscapes; cell phone towers are now as ubiquitous as the house sparrows were. Research in Spain proved that the microwaves released from these towers areharmful to house sparrows and the increase in the concentration of microwaves results leads to decrease in house sparrow and other bird populations. Dr Gyaneshwer Shukla, Naturalist, says: “The situation of sparrow can be compared to Guru Dutt’s film ‘Pyasa’. Sparrow has the status of ‘least concerned’ but fund grabbers have already started writing obituaries for sparrow.

The Homogenization effect

Urbanization presents novel challenges to native species by altering both the biotic and abiotic environment. One of these is the potential for ecological homogenization across cities: Homogenization of pattern and homogenization of process. The former describes increased similarity in the facets of biodiversity (species, trait, and phylogenetic composition) across cities whereas the latter addresses increased similarity in the operation of ecological processes, such as environmental filtering or habitat filtering in response to urbanization. (Aronson et al., 2016Pearse et al., 2018). Environmental filtering of species from a regional source pool (Keddy, 1992) has become a key conceptual framework for understanding the process generating patterns of urban biodiversity. Aronson et al. (2016) proposed a hierarchical set of filters at work in urban areas, from general biotic and abiotic filters including climate and land use, to characteristics of specific urban habitats, such as local scale human landscape management driven by socioeconomic and cultural factors. This hierarchical set of filters interacts with species traits to exclude certain species from the urban assemblage.

In particular, invasions of a similar suite of exotic species owing to human-mediated biotic interchange and extinctions of indigenous native species owing to habitat alteration and destruction may lead to a homogenized biota across the world's cities. This has been shown for continent-wide analyses by various studies. Mention we must this study by Madhusudan Katti and others (Frontiers | Effects of Urbanization on Native Bird Species in Three Southwestern US Cities | Ecology and Evolution (frontiersin.org) to substantiate the point. “Increases in prevalence of omnivores (e.g., American Crow) are likely due to these species' habits of scavenging human refuse, enabling them to exploit new niches present in urban habitats (Kark et al., 2007). Lim and Sodhi (2004) concluded that omnivores possess advantages in urban areas mainly at higher latitudes where food resources are seasonally limited. This meshes with the observed increases in omnivore prevalence and seasonal nature of climates of the cities. Increases in prevalence of native granivores (e.g., White-crowned Sparrow) are likely due to elevated levels of human bird feeding in urban areas. The decrease in insectivore (e.g., Blue-gray Gnatcatcher) prevalence in urban species assemblages may be due to the scarcity of insects in urban habitats. Changes in herbivorous invertebrates can translate to higher trophic levels (Flückiger et al., 2002), so habitat fragmentation, elevated pollutant levels, anthropogenic maintenance of yards, and planting of ornamental exotic species in urban habitats may drive declines in invertebrate diversity and abundance, which in turn cause decreasing prevalence of insectivorous birds (Tallamy, 2004Burghardt et al., 2009).

An Indian example that fits into the scheme is the House Crow. Why is it that the House Crow is such a successful species in human habitation areas in India? As Ranjit Manakadan stated: “Wastes from kitchens, restaurants, lunch boxes, weddings and parties are all thrown bewilderingly by the educated and the uneducated alike into the open. Then, there are the discards from the fish and meat markets and the filth of the open dump yards. Where else but in India do such bountiful conditions exist for the House Crow permitting them to proliferate? So, what is the harm if the crows increase in numbers? For one, the House Crow excludes many other birds (and other small animal) species from surviving in our rural and urban surroundings. Besides feeding on wastes, it is a predator of small birds, and the eggs and young of birds. Many of these species could survive with their own strategies if the crows were in normal densities that nature ordained them to be, but this is a case of dealing with a mob of intelligent predators.It has spread and colonised some parts of the Middle East, Africa and Southeast Asia, reaching these areas mostly by piggybacking onto ships. It is for this reason that governments of other countries pay a bounty for every immigrant ‘Indian Crow' (this is the term used, sometimes derogatorily, for the House Crow in colonised countries) shot — as it would otherwise disseminate the local fauna.”

Pushed to the Brink

This lone tragedy captured in their research “Extinction, courtesy Homo sapiens” by Ranjit Manakadan, Deputy Director, Ornithology, Bombay Natural History Society, is worth mentioning to drive home the point. “The Kauiaōō (Moho braccatus) bird of Hawaii is said to mate for life. The male seeks his soulmate by singing, and on pairing, both are known to sing a duet. In 1987, a lone male was heard singing out for his mate, waiting for her to respond – a response that never came. This was the destiny of a species that was once common in the forests of Kauai Island. The extinction the Kauaiōō is not a lone case in Hawaii – Hawaii is infamous for being the “endangered species capital of the world” and “bird extinction capital of the world”. Of the 64 endemic bird species of the Hawaiian Islands, about half are now extinct. The isolation of the island group in the middle of the Pacific gave rise to an unusually high proportion of endemic species, evolving sans mammalian and reptilian terrestrial predators. These species, besides other unknown species, got wiped out with the impacts of the arrival of Polynesian (300 and 1120ce) and European settlers (18th century).”

“Mauritius is another island that is synonymous with wildlife extinctions after the arrival of humans, with the classic case of the Dodo. This flightless species was wiped out by European sailors who started visiting the island in the 16th century, killing the birds for food. Dogs, cats, pigs, rats, and monkeys that got introduced into the island helped to further decimate the birds, which became extinct by 1681. Other than the Dodo, the island has seen the extinction of about 22 documented cases of wildlife, 13 of these being bird species.”

Talking about Indian native birds, Ranjit Manakadan says: “Among the Indian birds that have not been recorded for many decades and are presumed to be extinct/near extinct are Mountain Quail, Pink-headed Duck, and Green Peafowl. Jerdon’s Courser and Forest Owlet, earlier presumed to be extinct, were ‘rediscovered’ towards the end of the last century, but the present status of the former is again uncertain, with no records for the past few years despite intensive searches. Among the migrants to India is the Siberian Crane, which has stopped wintering in the Indian subcontinent. Until the 1990s, it was the ‘star attraction’ among the winter migrants at Keoladeo National Park, Bharatpur.”

Dr Gyaneshwer Shukla says: “As per my observation, the migratory Siberian Cranes lose their flight path and the flock and even get wayward due to lights in cricket stadiums when there is a match going on.”

Staring into the oblivion

Ranjit Manakadan says: “The “Sixth Extinction” juggernaut is on the roll in India, and is moving at a devastating pace with ‘human development’. The Cheetah has been lost, and so too the Mountain Quail and Pink-headed Duck, and probably also the Green Peafowl. Jerdon’s Courser is once again up on the Missing Species Poster. The Great Indian Bustard seems to be on its way out – unless a ‘miracle’ happens for this slow-breeding species that inhabits a human-impacted landscape. The future of the Gyps vultures will be put to test with the scheduled releases of captive-bred birds into the wild. And who knows what new threats (manmade or otherwise) will emerge in our country to impact or wipe out other species. India’s human population is undoubtedly the ‘mother of all problems’ for nature conservation in the country.” “Species (and habitat) extinctions are not new to planet earth, which has witnessed five mass extinction events since the first life forms appeared around 3.8 billion years. The causes for these extinctions were events such as climate change, glaciations, volcanic activity, and the impact of meteorites, and the process was spread over millions of years with new forms of plants and animals taking over. This is quite unlike the extinction process that is going on in this sixth species-extinction event. Never before in the earth’s history has the annihilation of so many species occurred in such a short span of time and as a result of one species, the Super Ape that tramples the earth,” he says.

Rays of Hope

Appalled, a coalition group in Philadelphia called ‘Bird Safe Philly’ has announced a ‘Lights Out Philly Initiative’ in order to organize an effort to dim the city’s downtown during spring and fall migration periods. The coalition includes Audubon Mid-Atlantic, the Academy of Natural Sciences of Drexel University, the Delaware Valley Ornithology Club, etc.  Reportedly, many others in the USA, including some of the tallest buildings in the city – BNY Mellon Centre, Comcast Technology Centre, etc, have committed themselves to participate in the National Light Outs initiative which calls on properties to turn off as many lights bas possible at night to protect migrating birds.

Conservation efforts afoot for the Great Indian Bustard include Project Godawan by the Rajasthan State government at Desert National Park. Under this programme, captive breeding will be carried out for the species recovery under the Integrated Development of Wildlife Habitat (IDWH).Both the Central Government and the Supreme Court have asked the power companies to ensure the power lines are done underground and the wind mills are installed with bird diverters. But what remains to be seen if the steps are actually implemented. In the meantime, hope is all we can cling on to.


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