The Silent Crisis: Human Influence on Bird Extinction

The serene landscapes of islands like the Canary Islands, Tonga, and the Azores, once havens of untouched biodiversity, faced irreversible changes with human settlement. Deforestation, overhunting, and the introduction of invasive species led to the extinction of numerous bird species. While documented extinctions since 1500 provide insights, the scarcity of fossils, especially small bird bones that decompose, obscures the true extent of global extinction.

An international research team utilised statistical models to estimate the "true" number of previously unknown extinct bird species since the Late Pleistocene, approximately 130,000 years ago. Unlike past studies relying on fossil evidence, this approach considered the extent of research within regions, revealing potentially undiscovered extinct species.

Professor Dr. Manuel Steinbauer notes, "So far, we knew from observations and fossils that 640 bird species have become extinct due to humans - 90 percent of them on islands." However, the research team's models suggest an alarming reality – an estimated 1,430 extinct species, around 11% of all bird species, leaving us with only around 11,000 today.

This study uncovers what scientists believe is the largest human-induced extinction of vertebrates in history. The arrival of humans on Pacific and Atlantic islands around three thousand years ago, coupled with the impacts of global sea travel in the 14th century, triggered significant waves of extinction.

Lead researcher Dr. Rob Cooke emphasises the profound human impact on avian diversity, showcasing the devastating consequences even small human populations have on bird populations. Habitat degradation, overexploitation, and the introduction of predatory animals contributed to these extinctions, many of which occurred before written records.

Professor Steinbauer underscores the importance of fossils in understanding extinction processes, revealing the fatal impact of human arrival on islands. The study not only sheds light on historical extinctions but also warns of ongoing threats. Human-induced factors such as climate change, intensive agriculture, and pollution continue to endanger bird species, with predictions suggesting the loss of up to 700 more bird species over the next century. This, Professor Steinbauer warns, will have catastrophic consequences, as the extinction of one species reverberates through entire ecosystems, disrupting vital ecological functions performed by birds.

The collaborative effort involved scientists from esteemed institutions such as the University of Gothenburg, Uppsala University, University College London, and the Zoological Society of London, among others. As we unravel the hidden toll of human impact on bird extinction, the study urges a deeper understanding of the intricate ecological systems and a concerted effort to address the ongoing threats faced by our avian companions.

Read the study here