Forensic skills of the poison posse

THERE is a futuristic feel about the Central Science Laboratory near Sand Hutton. Seen from outside, the sculpted white buildings look like the set for a science fiction film starring Arnold "Terminator" Schwarzenegger. Inside, there is a network of seemingly endless corridors and laboratories, all gleaming white.

There are plenty of scientists here, as you would expect - many wearing the trademark white lab coat. They are engaged on a range of research projects for the Department of Food and Rural Affairs, everything from sustainable crop production to environmental management, conservation and food safety.

Among them, in a small unit buried deep in the heart of the complex, is a modest team of biologists and analytical chemists who have played an important part in helping to save one of the region's most beautiful wild birds.

The red kite, with its long, forked tail and five-foot wingspan, is one of our most majestic birds of prey. It was once common across much of Britain, including Yorkshire.

After being declared "vermin" in the 16th century, however, they were persecuted to the point of extinction. The last red kites disappeared from Yorkshire about 150 years ago, and the great birds of prey clung on only in rural mid-Wales.

Then, in the late 1980s, a major programme began to re-introduce the red kites across the country - first in southern England and the Midlands and then, in 1999, in Yorkshire.

Between 1999 and 2003, 69 of the birds were released at the Harewood estate near Leeds. They went on to establish a flourishing breeding population of between 150 and 200 birds today.

Almost from the beginning of the re-introduction programme, however, a threat emerged that appeared to put the birds' future at risk. Red kites began to die of poisoning.

That was where the team at the Central Science Laboratory's Wildlife Incident Unit came in.

They are forensic scientists, but instead of examining evidence from crime scenes, they study the bodies of wild animals and pets that have died in suspicious circumstances, to look for evidence of poisoning.

Between 1999 and 2003, they investigated nine cases involving red kites from Yorkshire - and were able to prove conclusively that seven had been poisoned.

There was no suggestion, says the unit's head Mark Fletcher, that the birds were being deliberately targeted. There is no reason for anyone to do so, he says, because the birds, being mainly scavengers, are no threat to livestock.

More likely was that poisoned "bait" - in the form of rabbit or pheasant carcasses laced with pesticide or other poison - was being put out to try to kill foxes or crows.

Being scavengers, however, the red kites couldn't resist the prospect of an easy meal and ate the poison intended for something else.

"They were innocent casualties," says Mark. "They were almost certainly not being deliberately targeted, but if people are putting poison out with bait indiscriminately in the countryside, anything can be at risk."

Proving that a bird has been poisoned is one thing - finding out who did it is another. One of the roles of the Wildlife Incident Unit is to find evidence for possible prosecution of wildlife poisoners. But while there have been successful prosecutions for poisoning red kites - for example of a pig farmer in the south east who believed the birds were targeting his piglets - there have not been any in Yorkshire.

Part of the problem, according to Doug Simpson of the Yorkshire Red Kite Project, is that after taking the poisoned bait, the birds don't die straight away.

"They tend to fly away, perch on a tree, don't feel very well and then die," he says.

Because of that, Doug says, there has only been one case in Yorkshire where the dead bird was found next to the bait that killed it.

This makes it difficult to prove who was responsible. Even in cases of prosecutions that have been successful, such as that of the pig farmer, it wasn't for poisoning a red kite, says Mark Fletcher, but for illegal use and storage of pesticides.

The failure to successfully prosecute anyone in Yorkshire for the red kite poisonings does not detract from the value of the work done by the Wildlife Incident Unit, Doug says.

There have been no cases of poisonings in Yorkshire for more than two years. He believes that is in part down to the publicity surrounding the cases when the Wildlife Incident Unit proved birds had been poisoned.

"Their work has been of paramount importance," he says. "It has made people think again and stop doing it."

The Sand Hutton team investigates more than only red kite poisonings. They look into cases from all over England and Wales where accidental or deliberate poisoning is thought to be responsible for the death of wild animals and birds - everything from foxes and badgers to birds of prey and even honey bees.

They are also called in when cats or dogs die as a result of poisoning.

There are several reasons for doing what they do, Mark Fletcher says. Sometimes, a pesticide which is being used legally may have an unforeseen impact on wildlife populations.

That was what happened in the 1980s with honey bees.

The Wildlife Incident Unit investigated more than 100 cases in which bees from different hives had been poisoned by insectides used to spray, for example, oil seed rape fields.

The insecticide was being sprayed on the fields, the bees were foraging for nectar among the rape flowers - and were being poisoned.

Partly as a result of the unit's findings, the way insecticides are used now has changed. Instead of spraying rape fields while they are in full flower - when the bees are at risk - farmers have to wait until most of the flowers have died away.

Unless you are a bee-keeper, you might find it hard to get excited about saving the lives of bees, but they are extremely important creatures, Mark says.

"Bees are pollinators - the most important pollinators for many crops."

The other main reason for the unit's existence is to prevent the misuse or illegal use of pesticides, such as the laying of poisoned bait.

It is illegal to use such bait as a method of trying to control foxes, badgers or any other "vermin", says Mark Fletcher - and there are good reasons for that.

As a pest-control method it is indiscriminate. Yes, the poisoned bait may be eaten by foxes, but it could equally well be eaten by a harmless red kite or a much-loved family pet.

There is even a potential risk to human health from such practices, Mark adds.

"Some very good chemicals are very poisonous. People could pick up a poisoned bait. There are laws which say how pesticides can be used - and for good reasons."

:: What goes on in the Wildlife Incident Unit

Dead animals are usually reported to the Department of the Environment, Food and Rural Affairs (DEFRA) by members of the public, such as ramblers, dog walkers, farmers or gamekeepers.

A DEFRA wildlife adviser will visit the scene to collect the carcass, together with samples of pesticide and any other relevant information.

A post-mortem examination is then carried out by a DEFRA vet - and only if poisoning is suspected will samples be sent to the Wildlife Incident Unit for analysis.

There, members of the team first log in the sample. Their evidence could potentially be used in a court case up to two years later, points out senior chemist Ainsley Jones, so care and accuracy is essential.

The tissue sample is then dissolved using a special solvent, the resulting liquid "cleaned up" in the lab using an absorbent which filters out unwanted material, and the remaining liquid subjected to analysis in a chromatograph.

This gives a readout on a graph, in which the various spikes each represents a different chemical. The height of the spike also tells the analysts how much of the chemical is present.

:: What to do if you spot a dead animal

The unit relies on members of the public reporting dead wildlife and other animals. There is a DEFRA freephone telephone number to call: 0800 321 600.

It is important, however, not to put yourself at risk, Mark Fletcher says. If an animal has died from poisoning, that poison could pose a threat to you, too. So:

Avoid contact with animal carcasses, suspect baits, pesticides or pesticide containers

Where it is safe, cover dead animals, bait or pesticide so they won't be disturbed or pose a threat

Make a note of where and how you found them, then make a report on the freephone number.

:: Cases the unit has investigated

In 2004 alone, incidents of suspected animal poisoning the unit investigated from across the country included:

18 red kites

59 buzzards

13 owls

8 kestrels

15 foxes

12 badgers

3 otters

32 cats

55 dogs.

Among cases investigated of domestic animals thought to have died from poisoning was that of a police dog used in the search for a missing child in London. The dog ate poisoned biscuits it found on an allotment. The biscuits had been laid out in an attempt to kill either foxes or sparrows. The dog died, the culprits were prosecuted - and the missing child turned up safe and well.

Updated: 10:29 Friday, January 20, 2006