Saturday, 4 October 2008

World Wildlife Week: Common Birds Turn Rare In Cities While Efforts Continue To Save Green Space

Set a bird song as your mobile ringtone. For that may soon be the only way you get to hear from our winged friends — studies show that the increasing number of cell phone towers in cities is bringing down bird population.

While studies in Spain and Belgium have established the ill-effects of electromagnetic radiation (EMR) emitted by cell phone masts on birds, a study to be published next month by a team in Panjab University has found that EMR can damage bird eggs and embryos. The study, conducted in Chandigarh, is applicable to all Indian cities where cell phone masts are proliferating. Chennai has 4,000 cell phone towers, compared to about 200 in Chandigarh.

Researchers at the Salim Ali Centre for Ornithology and Natural History (SACON), Coimbatore, say there are enough reasons to attribute bird mortality to such radiation. "Cell phones and towers emit a very low frequency of 900 or 1,800 MHz, called microwaves. Studies have found that they can cause thin skulls of chicks and thin egg shells," says Dhanya R, a researcher at SACON.

The team at the Centre for Environment and Vocational Studies of Panjab University, headed by RK Kohli, exposed 50 eggs to EMR for durations of five minutes to 30 minutes. "All the 50 embryos were damaged. It's almost like being microwaved," Kohli told TOI.

Chennai-based zoologist Ranjit Daniels says four of the 200-odd Chennai birds — house sparrow (Passer domesticus), redwhiskered bulbul (Pycnonotus jocosus), brahmini kite (Haliastur indus) and spotted dove (Streptopelia chinensis) — have virtually disappeared. "Birds are known to be sensitive to magnetic radiation. Microwaves can interfere with their sensors and misguide them while navigating and preying," says Daniels.

WORLD WILDLIFE WEEK : Where have all the birds gone? Sparrows, Brahminy Kites, Red-Whiskered Bulbuls And Spotted Doves Have Disappeared From City Skies
Early in 2005, a friend threw a challenge at R K Kohli, coordinator of Centre for Environment and Vocational Studies, Panjab University: "Can you show me one sparrow on the campus?" Thinking it would be an easy task, Kohli agreed. "I won the bet, but it took me several days," says Kohli.

So, when the centre decided to study in December 2005, the impact of electromagnetic radiations (EMR), Kohli decided to include sparrows in the list of organisms that the radiations affect. Three years later, the study found microwaves (300 MHz to 300 GHz) emitted by cell phone towers and handsets responsible for damaging eggs and embryos. And that is just one of the urban factors driving out several species of birds out of the cities.

Chennai is no exception. According to zoologist Ranjit Daniels, at least four of the 200-odd species of birds of Chennai are fast disappearing. On their way out are house sparrows, redwhiskered bulbuls, brahminy kites and spotted doves. "These are birds which have always been around. Now they are nowhere to be seen," says Daniels, attributing it to an increase in population of rodents which steal eggs, disappearing open grasslands, rising temperature and modern bird-unfriendly architecture. "House sparrows used to live in crevices of buildings. The new glass houses don't leave any space for them," he says.

PA Azeez, senior principal scientist at Salim Ali Centre for Ornithology and Natural History, concurs: "Urban birds have the habit of finding an urban analogue for their wild nests. Pigeons, which are multiplying in large numbers in cities, find ventilators an analogue to their natural rocky confines. Whichever bird finds an analogue survive." That perhaps explains the case of the disappearing brahminy kites which nest only on very tall trees.

Azeez also blames the supermarket culture. "Gone are the days of malligai kadais (old provisions stores) where birds came to feed on food grains. Today everything is packaged. The colourful plants in city gardens do not offer enough nectar or fruits for these birds," he says. His
research student Dhanya R adds another cultural dimension to the food scarcity when she notes that bird feeding, once a regular ritual in Tamil Nadu homes, is no longer in vogue.

Daniels adds an unusual angle when he holds trees planted by urban planners as villains. "Originally, Chennai was a coastal area with bushes suited for several birds. Big trees with large canopies are not suited for birds like the bulbul and sparrows. With the expansion of city, many of these birds are migrating to the suburbs or farther," he says.

Since man domesticated chicken some 6,000 years ago, several birds have learnt to share his habitat, but now, modernisation is driving them out. Daniels says the kind of birds will keep changing with the urban habitat. "Sparrows might have come to Indian cities only in the last century. The Bible has repeated references of sparrows, indicating that they were in abundance in the Middle East 2,000 years ago. Tamil folklore has reference to chittukuruvi, but the word could mean any small bird," says Daniels. The message: Birds may come and go for a few centuries, which is just a miniscule span in the evolutionary cycle. As cities continue to grow, some birds, mainly scavengers like crows would proliferate at the expense of other birds. Experts may be divided on the reasons for the disappearance of birds, but everyone agrees on one bad news: Once gone, these b i rd s would never be back.

RARE SIGHT: Birds such as sparrows are becoming rare in cities

Scientific name: Pycnonotus jocosus Common name: Red-whiskered bulbul Local name: Thondaikoluthi
Characteristics: The red-whiskered bulbul has a brown plumage on its head with a black pointed crest. It has red tufts behind its eyes, a dark collar, white underparts and crimson red undertail coverts. Both the male and female red-whiskered bulbuls look alike
Habits: They are usually found in pairs. Redwhiskered bulbuls are largely sedentary and do not move around much. They feed on insects and fruits.
Habitat: Red-whiskered bulbuls inhabit trees, bushes and gardens in human settlements. They usually nest in bushes.
Reason for disappearance:
Shrinking bushes and gardens are the reasons for the disappearance of the red-whiskered bulbul

Scientific name: Streptopelia chinensis Common name: Spotted dove Local name: Manippura
Characteristics: The spotted dove is approximately the same size as as mynah. It's upper parts are pinkish brown with a grey tint. It has a spotted back with white chessboard pattern from its hind neck. It has a dark brown tail with a white border, white belly and white undertail. It has magenta legs and feet. Both male and female spotted doves look alike Habits: Spotted doves feed on grains. They nest on a small platform of twigs on trees with sparse canopy like babool and acacia. Habitat: Spotted doves are usually seen in pairs and occasionally in small flocks in cultivated areas, gardens and terraces.
Reason for disappearance:
Dense planting of trees and shrinking open spaces.

Scientific name: Haliastur Indus Common name: Brahminy kite Local names: Chemparunthu, Garudan Characteristics: The brahminy kite is the same size as an eagle. It has a chestnut-coloured body with white head, neck and breast and brown abdomen. Its wings are black at the tips. The young ones are brownish in colour. Both male and female brahminy kites look alike Habits: They feed on fish, frog, reptiles and small birds Habitat: They usually stay on coconut palms near water bodies.
Reason for disappearance:
The changing urban landscape is the main reason for their disappearance.

Scientific name: Passer domesticus Common name: House sparrow Local name: Oorkuruvi
Characteristics: The house sparrow is the same size as a bulbul. Male: The male house sparrow has a grey crown. The space between its eye and bill is black and so are the sides of crown behind its eye. Its upper back is chestnut in colour. It has black streaks on its chestnut coloured back. The male house sparrow also has a white patch on its shoulder, a dark brown tail and black breasts. The centre of its throat is also black while the sides are white. The rest of its under belly is grey. It has a dark brown bill and fleshy brown legs and feet.
Female: It has a dark brown back with greyish brown streaks, a brownish white under side and a pale brown bill. Habits: House sparrows usually keep in pairs or in noisy flocks. They feed on grass, weeds, fruits and insects. Habitat: House sparrows inhabits all human habitations.
Reason for disappearance:
Increasing heat in cities and changing urban architecture.