Study pitches for 5,000 artificial bird nests to mitigate impact of bullet train

Mumbai A study funded by the National High Speed Rail Corporation Limited (NHSRCL), which is executing the Mumbai-Ahmedabad bullet train project, has suggested the installation of 5,000 artificial bird nests along the 508.17 km alignment of the proposed railway line to mitigate the potential impact on avian biodiversity. The allocated budget for the nests is ₹8,48,458.

The study titled ‘Report on Mitigation Measures on Birds’ Nests Along the Proposed Alignment of Mumbai- Ahmedabad High Speed Rail Project’ was conducted in 2019 and submitted to the forest department last month as part of the process to obtain Stage-II forest clearance (FC). 

It found that the area of alignment houses as many as 55,446 bird nests, of which a large majority (44,897) were baya weaver nests. Of these, 10 percent of baya weaver nests are “active” because males of the species build multiple nests in a single area, but use only a fraction of them.  

The researchers noted, “Under this (bullet train) development, there will be an impact on biodiversity due to alteration/loss of habitat due to tree cutting and other activities. The study involves understanding the qualitative and quantitative impact on the avifauna nest and proposing mitigation measures for the same.”

Through primary data collection, researchers with Terra Nero (a Thane-based environmental consultancy were able to identify a total of 26 different bird species in the study area, while the presence of another 62 species was confirmed through secondary data collection (i.e., from academic publications in scientific journals and a range of environmental impact assessment reports).

“Out of the total avifaunal species observed, no species is found to be globally threatened as per the International Union for the Conservation of Nature,” the study noted.

Researchers also noted significant evidence that birds were breeding in the area. They observed specimens carrying food and nesting material, performing “distraction displays” to divert possible predators away from their nests (which may harbour young ones) and indulging in persistent alarm calls and agitated behaviour, which also indicates the presence of offspring nearby. Researchers noted the presence of nests across six different types of habitats, including forest land, rivers, scrubland, paddy fields, ponds and also human settlements.

HT reached out to Anjum Pervez, officer on special duty, NHSRCL, for a comment but did not receive a response on Tuesday.

Dipti Sharma, a Quality Council of India certified ecologist and founder of Terra Nero, said, “Based on our assessment of the project’s impacted area and the budgetary allocation, we arrived at a figure of 5,000 artificial nests which should be installed to minimise the project’s impact on birds, particularly through loss of habitat. It is very hard to predict how many of these nests will  be used. They are typically more successful in urban settings, with species such as sparrows. For baya weavers, nest building is an important part of their behaviour so they may not take to artificial nests at all.”

Terra Nero’s study recommends, “An optimal density of about 5,000 artificial nests is suggested to be placed in the study area as an effort towards rehabilitation of the disturbed birds. The artificial nests should be a mixture of a box type as well as platform and cup type nests made of materials usually used by birds. The placement of these artificial nests may be in a mixture of natural and modified habitats. It must be ensured that after placing the artificial nests, the overall carrying capacity of those habitats is not exceeded.”

Veteran birder and former director of the Bombay Natural History Society, Dr Asad Rahmani, said, “I cannot comment on this report as I have not seen it, but the use of artificial nests is not very effective at mitigating the impact of any project. Fortunately, birds are not as affected as terrestrial mammals by liner intrusions. Nevertheless, the project proponent should ensure that habitat restoration is carried out around the project area so that the birds do not move away due to loss of trees.”