A griffon vulture lies dead on brown soil

Raptors such as the griffon vulture are some of the birds most affected by lead poisoning from ammunition. Image © FJAH/Shutterstock

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Lead ammunition poisoning Europe's birds of prey

Toxic lead ammunition is putting Europe's birds of prey under threat.

Populations of raptors are over 50,000 birds smaller than they would otherwise be, with suggestions the scale of the issue could be far greater than previously realised. 

Over 55,000 birds of prey are missing from Europe's skies.

Populations of raptors are estimated to be up to 14% smaller than they should be due to the impact of lead ammunition, according to a study published in The Science of the Total Environment.

With almost a quarter of these birds of prey undergoing population declines in Europe, the toxic metal could be pushing some of our most recognisable birds towards extinction. 

Difficulties in gathering data mean these population estimates are likely to be an underestimate, with estimates for many birds of prey unable to be calculated.

The scientists behind the research have called for faster action as a ban on lead ammunition is being considered in both the UK and the European Union (EU).

Professor Rhys Green, the paper's lead author, says, 'The continued blanket use of lead ammunition means that hunting as a pastime simply cannot be considered sustainable unless things change.  

'Unfortunately, efforts to encourage voluntary shifts away from lead shot have been completely ineffective so far.

'The kinds of reductions in raptor populations suggested by our study would be considered worthy of strong action, including legislation, if caused by habitat destruction or deliberate poisoning.'

Public consultations on the banning of lead ammunition in the UK and EU have now closed, with reports on the possible options likely to be presented in the coming year

Discarded shotgun cartridge and lead shot

Missed and discarded ammunition can contaminate the environment for decades. Image © Click98/Shutterstock

What impact does lead shot have on the environment?

Lead has been used to make ammunition for hundreds of years. Its malleability and melting point make it easy to work with, while its density allows it to fly more accurately.

However, lead is also very toxic, with concentrations of the metal at any concentration known to cause deleterious impacts on the body. It acts in a variety of ways, from reducing the production of haemoglobin used in red blood cells to reducing fertility. 

While its impacts on humans are widely recognised, with bans on its use in products such as paint and petrol, the use of lead shot to hunt wildlife has persisted even though it is known to have devastating impacts on nature.

The effects of lead shot are twofold. The direct impact when it embeds itself in prey is that it builds up in the food chain, with top predators such as raptors accumulating significant amounts of lead from the prey they hunt or scavenge on. 

For the American golden eagle, this has seen the population growth rate shrink by around 1% as almost half of the birds suffer from chronic lead poisoning.

But many of the pellets in shotgun cartridges miss their target and end up scattered in the environment. These can persist for decades, leeching into the environment, poisoning the surrounding area and affecting the growth of local wildlife. The pellets can also be mistaken as food by wildfowl like ducks.

While a ban on lead shot being used to hunt wildfowl has been in place in the UK since 1999, research suggests that is ineffective with around 13 million ducks, or 77% of all those hunted, estimated to have been shot with lead shotgun pellets in the following 22 years.

Meanwhile, in Denmark, where a ban on lead shotgun ammunition has been in place since 1996, it is estimated that only around 3% of ducks are shot with lead.

A blanket ban, therefore, is likely to lead to a significant decline in the impact of lead on wild birds. While concerns have been raised over the costs and effectiveness of replacement ammunition, nine leading shooting and rural organisations announced they were looking to see the end of lead shot by 2025.

The recent study, on over 3,000 dead raptors from across Europe, has added to these calls for change. 

A white-tailed eagle in the rain

White-tailed eagle populations are one of the most suppressed by lead ammunition. Image © Ian McCarthy/RSPB

How does lead shot affect Europe's eagles?

Levels of lead from the livers of the dead birds was used to estimate just how badly lead ammunition was impacting the populations of Europe's birds of prey, which are already under pressure from human impacts such as persecution and egg collecting.

These samples were taken from carcasses collected over the past 50 years across 13 European nations. The lead levels were then compared with the number of hunters known in each country, which was used to model how large raptor populations could have grown without the impact of lead ammunition.

The scientists found that across Europe, the 10 raptor species studied were at least 6% smaller than otherwise expected. Unsurprisingly, the countries with a higher density of hunters had higher levels of lead poisoning in bird of prey.

Proportionally, the most impacted bird of prey was the white-tailed eagle, whose populations are 14% smaller than without the impact of lead. Other significantly impacted species are the golden eagle and griffon vulture, with populations 13% and 12% smaller respectively than they would otherwise have been.

However, while the buzzard only saw a decline of 1.5%, its large population size means it suffered one of the largest falls in terms of population numbers, at around 22,000 fewer birds than without lead ammunition.

Ongoing concerns over the impact of lead on wildlife and human health have seen chemical regulators in both the UK and the EU consider the introduction of bans on lead ammunition.

UK environment minister Rebecca Pow says, 'Addressing the impacts of lead ammunition will mark a significant step forward in helping to protect wildlife, people, and the environment.

'This is a welcome development for our new chemicals framework, and will help ensure a sustainable relationship between shooting and conservation.'

Since being launched last year, the reviews of lead ammunition use in the UK and EU have been gathering evidence and comments on its impacts. While both reviews are independent, any ban in the EU would likely impact the availability of such ammunition in the UK.

Reports on lead ammunition are expected to be delivered this year, ahead of possible legislation to be brought in due course.