The Lear's macaw (Anodorhynchus leari), a species endemic to the north of the state of Bahia, Brazil, nearly went extinct in the 1990s. Thanks to conservation efforts, its population has grown to 2,500 today. However, this expansion has coincided with the rapid growth of the region's power grid, which increased by approximately 30% between 2018 and 2023. Consequently, between January and August of 2025, 35 macaws were found dead with signs of electrocution — accidental death or injury caused by electricity.
To mitigate the problem, a study supported by FAPESP identified the locations most prone to this type of accident within the municipalities where the species is present. Ninety percent of the population is in the Raso da Catarina region. The mapping took into account 78 reported electrocutions between 2005 and 2022, the region's power grid composition, and the species' area of activity, among other factors.
The study, published in the Journal of Applied Ecology, reveals that modifying 10% of the poles with the highest risk could reduce known accidents by approximately 80%.
"The main objective is to identify priority areas for mitigation, where changes can be made to the poles to prevent further deaths and potential power outages. Our estimates indicate a good cost-benefit ratio for both the supplier and the conservation of the species," says Larissa Biasotto, a Brazilian based in the UK and senior science officer at BirdLife International. She is also the first author of the study.
While pursuing her doctorate at the Federal University of Rio Grande do Sul (UFRGS), Biasotto obtained data on Brazil's entire national power grid from the National Electric Energy Agency (ANEEL) via the Access to Information Act. She wanted to understand which bird species and biomes were primarily affected by the power grid.
One of the first results was published in 2021. The mapping indicated the Lear's macaw as one of the priority species in terms of the risk of electrocution and the development of mitigation measures.
When Biasotto published the article, the National Center for Research and Conservation of Wild Birds (CEMAVE), which is part of the Chico Mendes Institute for Biodiversity Conservation (ICMBio), linked to the Brazilian Ministry of the Environment, and researcher Erica Pacífico were observing a significant increase in the electrocution of the species in municipalities such as Canudos and Euclides da Cunha in Bahia, where Pacífico has been conducting her research since 2008. Based solely on the count of carcasses collected near power poles by residents, more than 70 birds had been killed since then.
"This is a conservative number because it doesn't account for all those that may have died in sparsely populated areas or whose carcasses were consumed by dogs or scavenger birds. It's estimated that in the Caatinga [a semi-arid biome in northeastern Brazil], an animal carcass lasts a maximum of three days," explains Pacífico. She is the coordinator of the Lear's Macaw Research and Conservation group, a postdoctoral researcher at the Institute of Biology at the State University of Campinas (IB-UNICAMP), and a co-author of the study.
The study is part of the project "Use of New Bio-Tracking and Analytical Tools for the Study of Movement Ecology and Bird Conservation in the Caatinga," which is supported by FAPESP and coordinated by Francisco Voeroes Dénes , a professor at the Institute of Biosciences at the University of São Paulo (IB-USP).
Fernanda Paschotto , who completed a master's degree at IB-USP on the life history and habitat selection of the Lear's macaw with a scholarship from FAPESP, is among the authors of the study.
Cost-benefit
Since 2008, Pacífico has continuously monitored the species, cataloging nests and counting the population. In 2017, the organization began using biologgers – collars that provide GPS location – to collect unprecedented information on the daily movement patterns of some Lear's macaws and to more accurately define their area of activity. This area largely consists of feeding sites where the licuri palm (Syagrus coronata) grows. The fruits of this palm tree are the macaws' main food source. Notably, areas where licuri palms grow are where most of the reported electrocutions occur.
"One of the innovations of the study is that we didn't use the species' distribution area as a whole, as is usually done in this type of mapping, but rather the area of activity, where the probability of electrocution is higher. It's in these places that they spend most of the day, feeding, interacting with each other, and perching on poles and medium-voltage wires. Because they're taller than the native vegetation, these points offer a privileged view of the territory," says Biasotto.
Animals can be electrocuted when they touch a wire carrying an electrical current at the same time as another wire that does not carry current or has a lower voltage. For this reason, the Bahia Public Prosecutor's Office proposed a solution through a Conduct Adjustment Agreement: increase the distance between the wires, which requires replacing poles, a task initiated by the company.
According to the cost-benefit analysis carried out by the researchers, mitigating the possible effects on 1% of the poles in the areas with the highest risk of electrocution could prevent 35% of accidents, requiring intervention on at least 5,668 poles.
However, since this reduction could be insufficient for the population's viability, the authors also performed calculations considering 5% of the highest-risk area (22,037 poles), which would prevent 60% of electrocutions.
Extending the modeling to 10% and 20% of the highest-risk areas would require changes to 37,412 and 63,966 poles, respectively, and would result in reductions in accidents greater than 80% and 90%, respectively.
Conservation
The Lear's macaw is currently classified as "threatened" on both the Brazilian list of endangered species and on the list of the International Union for Conservation of Nature ( IUCN ). According to ICMBio's National Action Plan for the Conservation of Birds in the Caatinga , its population is estimated at less than 2,600 individuals. Therefore, the authors argue that reducing fatalities by 60% may not be enough to ensure the species' long-term viability.
"Until we have a population viability study for the species, a reduction closer to 90% would be more cautious, making changes to 10% to 20% of the poles," Pacífico argues.
According to Biasotto, replacing the poles would likely be costly. Another solution would be to develop devices that insulate electrical structures and provide safe landing places for birds. One approach is to insulate the wires with non-conductive plastic tubing. This solution is used in Europe to protect birds of prey, which are the main victims of electrocution there.
"However, in the locations where they were installed for testing in Bahia, the structures were damaged, probably due to weather conditions and improper installation," says the researcher.
Unlike solitary predators, macaws congregate in groups of up to 50 individuals, explore their environment extensively, and can easily destroy material with their powerful, sharp beaks. Therefore, a device suitable for the semi-arid region and its birds must be developed.
In addition to guiding future accident mitigation actions and protecting the Lear's macaw, the researchers argue that the mapping model could, in the future, include other bird species in the region. The most emblematic example is the Spix's macaw (Cyanopsitta spixii), which is extinct in the wild but is currently part of a reintroduction program. Due to its similar habits to those of the Lear's macaw, the Spix's macaw could benefit from an electrocution mitigation project as well.
In his book about the saga to save the Spix's macaw, author Tony Juniper suggests that the last individual of the species died from electrocution.
About São Paulo Research Foundation (FAPESP)
The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe .
