Vanishing crows, a wake-up caw

Survey claims that crow population is decreasing due to lack of nesting space

Vanishing crows, a wake-up caw

 Not only sparrows, but even crows are deserting Bangalore City.

Their numbers have reduced drastically over the years, according to ornithologists and other experts.

This, they say, is because of an increase in the number of buildings and disappearing tree cover. 

This also raises questions about the sensitivity of the government towards the City’s ecology, as unplanned felling of trees has reduced the population of these birds.

A team from the Centre of Ecological Sciences of the Indian Institute of Science (IISc) conducted a survey of crow population sometime ago. The team found the number of crows was reducing in the City primarily due to lack of nesting spaces. 

Trees are being cut down to make way for infrastructure works, especially high-rise buildings.

Another reason is the increase in the population of Blue Rock pigeons, which unlike crows, can roost in buildings. 

Even cuckoos are threatening the population of crows. Cuckoos not only lay their eggs in a crow’s nest but also drop the host’s eggs to the ground. The team found that despite being scavengers and sturdy, crows were facing competition from kites, which too feed on garbage, bandicoots, rats and carcasses. 

Injuries

They also observed that earlier, when crows got injured, others would come to their rescue. But of late, that behaviour was not seen.

The IISc team also observed that people used to feed crows during festivals like Mahalya Amavasya or on Saturdays. But these practices were fading away, reducing the food source for crows.

“Another important reason is the City had become cleaner and thus the garbage on which crows used to feed has reduced,” said Prof T V Ramachandra, Energy and Wetlands Research Group, CES, IISc.

Dr S Subramanya, Professor of Entomology, Gandhi Krishi Vignan Kendra, University of Agricultural Sciences, said, “Though we have not done any formal study, we have noticed reduction in their numbers. 

This is because crows’ nesting spaces have reduced. Indiscriminate cutting of trees is the prime reason. But in some pockets like Lalbagh and GKVK campus crows can be seen.”

Jungle crows

He said jungle crows can still be seen, compared to house crows. Jungle crows are hunters while house crows are scavengers. 

Some years ago, one could see many jungle and house crows thriving on waste around dump sites, like Mavalipura, but now more kites are seen.

Change in lifestyle and introduction of more commercialised food items like packed food are the prime causes for the loss of such important bird species, Subramanya added.

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