{"id":2185956,"date":"2025-03-02T06:00:46","date_gmt":"2025-03-02T05:00:46","guid":{"rendered":"https:\/\/focusingonwildlife.com\/news\/?p=2185956"},"modified":"2026-02-07T06:47:00","modified_gmt":"2026-02-07T05:47:00","slug":"humans-main-factor-in-spanish-bonellis-eagle-decline","status":"publish","type":"post","link":"https:\/\/focusingonwildlife.com\/news\/humans-main-factor-in-spanish-bonellis-eagle-decline\/","title":{"rendered":"Humans main factor in Spanish Bonelli\u2019s eagle decline"},"content":{"rendered":"

Electrocution, poisoning, shooting and even drowning have led to an alarming death rate of Bonelli\u2019s eagles in eastern Spain.<\/p>\n

Recent findings on the state of these raptors have led researchers to call for further conservation action to protect the birds and their ecosystems.<\/p>\n

\u201cThe whole population has been declining for several years,\u201d said Andr\u00e9s L\u00f3pez-Peinado, a PhD student studying biodiversity at the University of Valencia.<\/p>\n

Bonelli\u2019s eagles (Aquila fasciata) live in coastal areas of the Mediterranean as well as in patchy areas in Asia, from the Arabian Peninsula to Indonesia. In some areas, populations are stable, but in Spain, researchers suspected an unsustainable death rate may be causing declines.<\/p>\n

In a study published recently in the Journal of Wildlife Management, L\u00f3pez-Peinado and his colleagues analyzed data from 60 Bonelli\u2019s eagles fitted with GPS devices attached by backpack harnesses from 2015 to 2023 in northern Valencia and in neighboring Castilla-La Mancha.<\/p>\n

Why are Bonelli\u2019s eagles declining?<\/h2>\n

Some 33 of these birds died during the research period. The researchers detected deaths through a lack of movement on the GPS devices and brought the carcasses to veterinarians for necropsies. The results of these tests revealed that two-thirds of the dead birds died from anthropogenic causes, while about 27% died from natural causes\u2014all but one, which succumbed to disease, died from predation. The final 6%\u2014two birds\u2014died of unknown causes.<\/p>\n

Of the birds that died from human causes, the main reason was electrocution on power lines\u2014a problem that has been found to affect raptors in many parts of the world, from Mongolia to the United States. Among the birds these researchers studied, about 18% died from electrocution, while about 9% died from collisions with power lines.<\/p>\n

Poisoning was a close second at 15% of the eagles that died. L\u00f3pez-Peinado and his colleagues said that these instances were likely intentional, as was the case for the 9% of eagles that were shot. Pigeon fanciers\u2014people who breed and care for pigeons\u2014will sometimes use bait pigeons with carbofurans\u2014a pesticide banned in the U.S. and many parts of Europe\u2014smeared on their plumage to remove eagles they perceive as a threat from the area. When eagles prey on the pigeons, they become poisoned. All three shootings occurred outside of the hunting season for other birds, during a time when firearms weren\u2019t allowed in the area.<\/p>\n

\u201cIntentional persecution of Bonelli\u2019s eagles and raptors, in general, is far from being eradicated in eastern Spain,\u201d the authors wrote in the study.<\/p>\n

\"Bonelli\u2019s
Bonelli\u2019s eagle have a large distribution, including in India, as this bird pictured. Credit: Birds of Gilgit-Baltistan<\/figcaption><\/figure>\n

Will Bonelli\u2019s eagles go extinct in parts of Spain?<\/h2>\n

The researchers calculated what this level of deaths means for the population in this area. They found that if mortality continues at this rate, there is a 99.2% chance that the birds will be extirpated from the area in the next 100 years.<\/p>\n

\u201cThe risk of losing that small population\u2014if we are not depending on immigrants\u2014is almost 100%,\u201d L\u00f3pez-Peinado said. As a result of this research, the province of Valencia has listed the eagle as endangered. In the rest of Spain, it\u2019s listed as vulnerable. In fact, he said that the population in the southeast of Spain is the only one that is still doing OK.<\/p>\n

Luckily for the Valencia area, immigrants from other populations come in, but the problem remains for Bonelli\u2019s eagles in the larger region.<\/p>\n

L\u00f3pez-Peinado said that part of the problem is that a lot of the deaths are occurring during the breeding season, which can stop the growth of future generations.<\/p>\n

While most people think that this species does better in coastal areas, this wasn\u2019t necessarily the case in terms of deaths. Along the Mediterranean, more eagles died from human causes, while in the interior, more birds died from natural causes.<\/p>\n

Another problem is a lack of protected areas, L\u00f3pez-Peinado said. Most of the deaths\u2014particularly the human-caused ones\u2014occurred outside of protected areas. The trouble is the protected areas aren\u2019t big enough for these wide-ranging raptors, L\u00f3pez-Peinado said, and some of those that exist aren\u2019t well managed ecologically.<\/p>\n

How can we save Bonelli\u2019s eagles?<\/h2>\n

To address this problem, he and his colleagues are currently speaking with the administration of protected areas to implement management. Some improvements that might help the eagles include opening up the forest canopy to give them more areas to hunt, for example.<\/p>\n

Other potential measures that might benefit the species include retrofitting power lines to make electrocution less likely. Since three birds in the study died due to drowning in water tanks\u2014they go in for water and have no way to get out\u2014L\u00f3pez-Peinado said that building ramps or fencing these water sources off better might also help reduce the deaths from human causes.<\/p>\n

\u201cWe are losing habitat and increasing the anthropogenic causes of death,\u201d he said. \u201cIf we want to reduce this problem, we have to focus on getting a better area for them and reducing the deaths.\u201d<\/p>\n

This article<\/a> by Joshua Rapp Learn was first published by The Wildlife Society on 14 February 2025. Lead Image: A Bonelli\u2019s eagle in Spain. Credit: Francesco Veronesi.<\/i><\/p>\n

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