Between 25 and 100 million birds are injured or killed each year due to human activities. This figure emerges from the first comprehensive study on the causes of bird mortality in Spain. Analyzing 272,655 records, the report attributes 59.5 percent of injuries or deaths to human action.
The study was authored by SEO/BirdLife, a conservation NGO, which reviewed data from fauna rescue centers across all autonomous communities between 2000 and 2018. Collisions with power lines stand out as the leading cause of unnatural bird deaths, accounting for nearly 40 percent of cases.
Illegal collection for captive breeding ranks second, representing more than 20 percent. Other contributors include electric shocks, poisoning, wind turbine collisions, and poaching, which together complete the primary causes list.
Data that had not previously been consolidated into a single database were gathered by SEO/BirdLife within the LIFE Guardians of Nature framework. The information from rescue centers reflects birds found by people or authorities and not the entire population, but statistical modeling is used to project broader trends.
The model indicates a range from 25 million to 100 million birds affected each year. Even the lower bound remains substantial, given the infrastructures and field activities that expand in natural areas every year, many of which are prohibited by law. Asunción Ruiz, executive director of SEO/BirdLife, emphasizes that at least 25 million birds suffer injuries or deaths annually.
fixable issues
Many problems identified in the report can be addressed. Collisions with power lines and electric shocks are preventable through targeted measures. The findings reinforce the need for coordinated biodiversity conservation efforts involving governments, businesses, and the public when engaging with natural resources or enjoying outdoor activity.
Nicolás López-Jiménez, a coauthor and head of Species at SEO/BirdLife, notes the importance of understanding how corpse disappearance rates and detection rates affect the calculations. The study also highlights that protected and threatened species are disproportionately represented in the rescue records, underscoring the urgency of safeguarding vulnerable birds.
Approximately 22.66 percent of records involve species listed in the Red Book of Birds in Spain as facing the highest extinction risk. The legal protections around these species intersect with their presence in rescue data, illustrating the broader conservation challenge.
Considering legal protection, most affected species fall under special regimes, with 64.82 percent of records in taxa listed under the List of Wild Species Under Special Conservation Regime and 6.78 percent in categories officially deemed threatened by public administrations, including the Spanish Catalogue of Threatened Species.
Among the most endangered birds documented in 2023 is Montagu’s harrier. The Red Book classifies several species as Endangered or Vulnerable, and the report notes a sharp decline for certain raptors and other birds, underscoring the need for intensified monitoring and protection.
Goldfinch, leader in the number of entries
Two Endangered species, the Mediterranean Cory’s Shearwater and the Red Kite, appear alongside four other Vulnerable species with more than ten records per year. Between ten and one hundred records per year include one Critically Endangered species, several Endangered species, and multiple Vulnerable species.
In total, 348 species entered the rescue centers for anthropogenic reasons over the past decade. The goldfinch leads with the highest number of records (11,732), followed by the kestrel (10,167), the hawk (8,608), the griffon vulture (7,426), the yellow-legged gull (7,196), the swift (6,266), and the eagle owl (6,215).
For 34 of the most recorded species, the primary reason for entry was injuries from power-line collisions. Notable among these are the kestrel, swift, eagle owl, yellow-legged gull, and white stork.
Other notable drivers include illegal capture for captivity, involving species such as the European goldfinch, greenfinch, common linnet, and several passerines, as well as larger birds and raptors.
This electric shock hazard notably affects the eagle owl, the short-toed eagle, and the golden eagle. Wind turbines emerge as a major danger for griffon vultures and red kites, while agricultural machinery also contributes to mortality, particularly for Montagu’s harrier. Light pollution is identified as the principal unnatural cause of death for the Mediterranean species represented in the study.
David de la Bodega, head of the SEO/BirdLife Law Program, frames the study as foundational work aiding the conservation network that monitors wildlife across Spain in collaboration with perimeter police and conservation teams.
Reference report: marked in the project materials as the Mortality of Fauna Final Report, produced within the LIFE Guardians of Nature framework.