- A new study finds that white-bellied sea eagles nesting on towers along Odisha’s coast produced fewer fledglings, than those nesting on trees.
- Nests close to human settlements and far from waterbodies had lower breeding success, producing fewer young.
- Researchers say these artificial structures may be acting as ecological traps, raising the need to restore native trees and prevent human disturbance during breeding season.
Torrential rain and strong winds frequently lash Odisha’s cyclone-prone coast, uprooting tall trees that once served as natural nesting sites for white-bellied sea eagles. As their coastal habitat changes due to frequent tropical cyclones as well as urban development activities, these raptors have been increasingly spotted nesting on telecommunication towers and electric pylons. However, new research, published in the Journal for Nature Conservation, raises concerns that artificial structures may be acting as “ecological traps” in rapidly-changing landscapes.
While these structures are tall and provide clear vantage points to hunt for prey, the study observed, over four breeding seasons from 2021 to 2025, that nests built on towers consistently produced fewer fledglings than those built on trees.
White-bellied sea eagles use the same nesting sites for years, making them vulnerable to habitat changes. While they have been sighted nesting on artificial structures in the country before, this study tries to understand the costs of this shift in detail. “This research is the first of its kind in India, where we have differentiated the breeding output of a raptor in different nesting structures,” said B. Anjan Kumar Prusty, head of the Department of Environmental Science at Berhampur University, Odisha, and the study’s corresponding author.
Monitoring nesting
Some studies on raptors such as ospreys and white-tailed eagles in other countries recorded comparatively higher productivity in artificial structures, explained Sakti Prasad Pattnayak, a Ph.D. student at Berhampur University and the study’s lead author. “However, I have seen the opposite here,” he added.
To understand why, the team monitored 33 nests along 574 kilometres of Odisha’s coastline, between the Subarnarekha estuary and the Bahuda river. Between 2021 and 2025, they surveyed these nests every 10 days, recording 91 nesting attempts, most of which were on artificial structures.
The researchers used fledge rate — the number of fledglings that left the nest relative to the total number of eggs that hatched — as a predictor. “Productivity was quantified using fledge rate because it captures post-hatching losses that a simple ‘success/failure’ metric can mask,” explained Prusty.
The team calculated the proportion of waterbodies, built-up area and other landscape variables in a buffer zone of 2.1 kilometres radius around each nest. They also measured distances to roads and settlements, along with human population density and night-time light intensity as indicators of urbanisation.
The study results showed that natural nesting structures in the study area had a 100% success rate, with all nests producing at least one fledgling. In contrast, 39% of nesting attempts on artificial structures failed. Those that succeeded consistently produced fewer fledglings.
It also found that nests around areas of high human population density, close to roads and settlements but far from waterbodies produced fewer fledglings. Artificial nesting sites were typically located in these areas. “This tells us that artificial structures are placed in bad habitats compared to natural structures,” said Pattnayak.
Human presence near breeding birds may increase stress, leading them to abandon nests or their young. Since these raptors rely on aquatic prey such as fish and sea snakes, nests built close to waterbodies reduce the time and energy needed to forage, increasing chances of nestlings’ survival. Access to prey and exposure to human disturbance thus emerged as key factors driving breeding outcomes in this species, consistent with earlier research.
Ecological traps in changing landscapes
The clear difference in reproductive success led researchers to suggest artificial structures may be acting as ecological traps. “Practically, it reframes tower nesting from a simple ‘adaptation success story’ into a management concern. Artificial structures may concentrate breeding in disturbed matrices, potentially reducing population resilience over time if such nesting becomes dominant,” explained Prusty.
Nests on these structures also face added risks of being removed during maintenance work on towers, or electrocution in the case of high-voltage pylons.
White-bellied sea eagles remain understudied, remarked H. Byju, a researcher specialising in shorebirds at the Centre of Advanced Study in Marine Biology, Annamalai University, Tamil Nadu. He was not part of Pattnayak’s research. “This is the first comprehensive study on this particular species in India. All other studies were limited to population, sighting and nesting records. This has gone beyond that into breeding success rates, which is a very good insight into this species’ ecology,” Byju shared.
In Tamil Nadu, more records of these raptors nesting on pylons have emerged since Byju’s observation in 2023. “It has been seen as a pattern now,” he said.
Apart from frequent tropical cyclones, casuarina plantations and urban development activities are also shaping Odisha’s coastline. White-bellied sea eagles prefer building their nests on casuarina or eucalyptus trees planted as cyclone buffers. Casuarina (Casuarina equisetifolia) grows fast and is harvested for timber, but is not native. “They are not supporting biodiversity,” said Pattnayak, about the trees.
Because they are apex predators, the presence of these raptors is an indicator of a healthy coastal ecosystem. With rapidly-changing landscapes along the eastern coast, however, these birds are losing their natural nesting habitats and inhabit what Byju calls a “shaky environment.”
Guidelines for breeding season
The recent study did not measure electromagnetic fields (EMF) on electric pylons, but suggests that future research assess this. Byju also recommends volunteers to regularly monitor these nesting areas.
The International Union for Conservation of Nature (IUCN) lists white-bellied sea eagles as species of least concern. The 2023 State of India’s Birds report, however, indicates a rapid population decline in the long-term. In India, their nests are also reportedly declining.
Study authors note that conserving natural nesting areas by protecting tall trees and planting native, cyclone-resilient varieties near waterbodies is crucial. These could include banyan (Ficus benghalensis), coconut trees or even mangrove varieties, according to Pattnayak. Prusty added that the raptors also used to nest on peepal trees (Ficus religiosa) in the past.
However, since the birds currently prefer casuarina and artificial structures, limiting maintenance work during the breeding season, which runs from October to May, is equally important. Artificial structures must eventually be placed in suitable nesting habitats, where human interference is minimal, added Pattnayak. Towers and pylons also need to be retrofitted and insulated to ensure birds’ safety.
“Without community, there is no conservation,” remarked Byju, emphasising the need to involve local communities and increase awareness among maintenance crew. “If that can be done, it will go a long way in helping these birds survive a breeding season,” he said.
Read more: Decline in white-bellied sea eagle nests in coastal areas raises concerns
Banner image: A white-bellied sea eagle nesting on an electric pylon along Odisha’s coast. Such pylons expose raptors to several risks, including nest removal by maintenance crew and possible electrocution. Image by Sakti Prasad Pattnayak.
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