Lingering lead: how science changed the fortunes of millions of birds

As a citizen of the Roman Empire, traces of lead would have been everywhere, in your wine, water, and around your home.

This silent poison in everyday life is one of the earliest known examples of the threats of lead exposure to human and animal health. It has even been associated with, among other factors, the decline of the Roman Empire.

Since the Romans, lead has been linked to multiple public health issues, posing particular risks to young children and pregnant people. High-level or chronic exposure can lead to severe neurological damage and even death.

The ever-widening body of research on the negative health effects of lead has meant it has been banned for many uses, from paint to plumbing, petrol to children’s toys. And work continues across the globe to restrict many other uses.

But while efforts have been made to reduce human exposure, lead contamination, particularly from ammunition, has continued to cause significant damage to our natural world largely unabated.

In Britain, 7,000 tonnes of lead ammunition is discharged into the environment annually, poisoning wildlife, soils and watercourses, where it lingers for centuries. Studies suggest that this lead poisoning kills up to 100,000 UK waterbirds every year, and a million in Europe, making it a severe and significant environmental issue.

Last year the UK Government made a vital move, becoming one of just a few countries globally to commit to significantly restricting the use of lead shot and bullets. This April a three-year transition period began towards a full ban on lead shot and large calibre bullets for shooting.

It’s a historic policy win, and an enormous boost for nature in 2026. If properly enforced it will save huge numbers of birds, at least a million over the next decade, while also benefitting the wider environment and local communities.

What’s clear though is that this would not have been possible without many years of research.

Birds are particularly vulnerable to lead poisoning as many ingest shot and bullet fragments when they scavenge or prey on animals or consume pellets from the environment mistaken for grit or seed. The impacts of this poisoning are so significant that they have been documented in birds for over 100 years by scientists across the globe.

In the UK, the last five decades of intensive research has been spearheaded by Debbie Pain, Rhys Green, Ruth Cromie and Julia Newth (RSPB, Wildfowl and Wetlands Trust and the University of Cambridge). This steadfast four’s work has looked at the conservation, human health and social impacts of lead ammunition across the UK and Europe.

Their published studies have uncovered the lethal and sublethal effects of lead in birds; showing that many suffer significant pain and debilitating conditions as a result. Lead poisoning also negatively impacts on reproduction, with wider population effects.

Their research has also provided evidence to help drive forward legislation and uncover non-compliance with existing initiatives and regulations. For example, ‘kitchen autopsies’ on game meat during a five-year voluntary lead shot phase from 2020 showed a shocking 99% of pheasants and 100% of red grouse purchased, and from which shot could be extracted, still had lead ammunition present in them at the end of the supposed phase out. The levels of lead in supermarket game meat were also much higher than legal limits for meat from domestic animals.

Within the wealth of global scientific literature, this wide-ranging long-term research has provided a comprehensive evidence-base which undoubtedly enabled the UK Government to take the vital steps to restrict lead ammunition we have seen this year.