Extinction is a natural biological process. However, the current rate at which species are disappearing is vastly accelerated beyond the typical background rate observed in the fossil record. This rapid loss of biodiversity is widely recognized as the sixth mass extinction event, and unlike previous events, this one is driven almost entirely by human activity. The public interest in the “latest” animal to vanish highlights the urgency of this crisis.
The Most Recently Declared Extinction
The most recent animal to be formally declared globally extinct by an international body is the Slender-billed Curlew (Numenius tenuirostris). The International Union for Conservation of Nature (IUCN) officially moved the species to the Extinct (EX) category in 2025, marking the loss of a unique migratory bird. This declaration signifies the end for a species that was once relatively widespread across a massive geographical range.
The Slender-billed Curlew was a shorebird known for its long, thin, down-curved bill. Its breeding grounds were in the remote peat bogs and steppes of Western Siberia and Kazakhstan. Its wintering sites spanned the wetlands and coastlines of Europe, North Africa, and the Middle East. This reliance on multiple habitats across continents made it particularly vulnerable to human impacts.
The last confirmed sighting of a Slender-billed Curlew was in February 1995, photographed at Merja Zerga, a coastal lagoon in Morocco. Despite decades of dedicated searches, no verifiable evidence of the species has been recorded since that time. The 2025 designation makes it the first mainland bird species in Europe and West Asia to be globally extinct in modern history.
The long delay between the last sighting and the final declaration underscores the rigorous scientific process required for formal extinction status. The difficulty in pinpointing the final individuals made the formal assessment a drawn-out, methodical procedure.
How Scientists Confirm a Species is Gone
The process of declaring a species extinct is a methodical, evidence-based determination made by scientific bodies like the IUCN. A species is classified as Extinct (EX) only when there is “no reasonable doubt that the last individual has died.” This high standard is necessary to prevent the premature cessation of conservation efforts.
To meet this criterion, scientists must conduct exhaustive and systematic surveys across all known and expected habitats of the species. These surveys must be carried out at appropriate times of the day, season, and year, and must extend over a time frame suitable to the species’ life cycle. For long-lived species, this search period can span decades, explaining why the formal declaration often comes many years after the last confirmed sighting.
A separate designation, Extinct in the Wild (EW), is used for species that no longer exist in their natural habitat but survive in captivity or as a population outside of their historical range. A well-known example is the Spix’s Macaw, which was declared EW in 2019 but continues to be the focus of intensive captive breeding and reintroduction programs. The distinction is a fundamental difference for conservationists.
The cautious approach helps scientists avoid what is colloquially known as the “Romeo error.” This occurs when a species is declared extinct prematurely, leading to a withdrawal of protective measures that might have saved a remnant population.
The Causes Behind Modern Species Loss
The primary driver behind the modern extinction crisis is the accelerating impact of human activity on the planet’s ecosystems. The four major anthropogenic factors—habitat destruction, invasive species, climate change, and overexploitation—often combine to push vulnerable populations past the point of no return. For the Slender-billed Curlew, a combination of these pressures proved fatal across its migratory route.
The extensive drainage of its breeding grounds, primarily peat bogs and steppes in Central Asia, for agricultural expansion and development led to the large-scale loss of its necessary habitat. Furthermore, the coastal wetlands and estuaries the curlew relied upon for winter feeding were also increasingly degraded and lost to urban development and industrial use. The fragmentation of this vast habitat meant that even small populations could not sustain themselves.
Historical overexploitation, specifically hunting along the curlew’s extensive migratory flyway, also played a significant role in its initial decline. The species was a target for hunters in various countries, with this constant pressure preventing the already reduced population from recovering.
Climate change exacerbates the effects of habitat loss for many species. Changing weather patterns and temperatures alter the delicate timing of food availability and migration cues, creating an additional layer of stress on vulnerable populations. The loss of the Slender-billed Curlew serves as a reminder that the health of global ecosystems, particularly migratory pathways, is under severe duress.