Friday, 23 January 2009

Raptor poisonings - let's see the evidence

What happens when a bird of prey is found poisoned? It's a crime scene, with all kinds of forensic evidence ready to be discovered – or ignored.

All we hear is that Bird A was found dead on Estate B, and the lab says it was killed by Poison C. Estate B has a shoot, so the keeper is guilty, QED.

But that doesn't necessarily follow. If a murder victim was found poisoned, the police would investigate the possibilities. The victim might have been poisoned elsewhere, and staggered to that spot before falling dead. Or the body might have been carried there and dumped.

So it is with birds of prey. Some poisons (eg Yaltox [carbofuran]) will drop a bird in its tracks. But others act much more slowly. A bird eating a bait laced with alphachloralose, nitroxynil or mevinphos, for example, could fly a kilometre or more before dying.

And of course there are plenty of reasons why someone might want to 'plant' a dead bird to get an estate or an individual in trouble. It could be an ongoing squabble between individuals, or just an anti-shooting extremist.

I'm sure that the people investigating raptor poisonings are aware of all this, but do they carry out a thorough forensic job at the crime scene? Checking, for instance that the bird is still lying in the position in which it died? Taking detailed photographs and noting tyre tracks, footprints and any other evidence in the vicinity?

All we get to see is the bare statistics – and they raise more questions than they answer. For instance, bearing in mind that carbofuran causes instant death, why are there so many cases of dead birds found with no mention of a bait? And why so few multiple kills? You'd expect a hare or rabbit carcass poisoned with carbofuran to collect 4 or 5 buzzards, not to mention crows and flies.

Next time there's a poisoning incident, I'd like to see the forensic report that shows not just what killed the bird, but how it got there. Then perhaps we can start to answer the conspiracy theories about the 'planting' of poisoned birds by persons unknown.


Dr Dan Holdsworth said...

Here's something to think about: whereas in a mammal ingesting a rapidly-acting poison will usually drop it in its tracks, a bird may not be quite so easily affected since the first part of a bird intestine is the crop, which is essentially just a storage sac and doesn't absorb much from the food.

So, I'd say it would be quite possible for a raptor to land, scoff a portion of a poisoned carcass and take off again well before the poison has time to act; a bird in flight will also have most of its blood diverted to the flight muscles and only a bare minimum in the gut, so if it eats then flies off again it'll only start being affected when it lands and starts to digest what it ate.

The Fox said...

Dr Dan Yaltox stops them on the spot !!!!!

vicky payne said...

An interesting idea and one which bears investigation but it brings us back to the main blog thread- we need hard evidence not unsubstantiated accusations. Every dead or missing raptor goes straight to press as 'killed by nasty gamekeepers' when myriad other things could have happened; hill farmers, pigeon fanciers, fancy poultry keepers could all have issues with rogue raptors. They could accidentally eat baits destined for other animals, or just fail to survive as darwinism has not deemed them fit enough! I am not naive enough to think no keepers kill raptors but they are not the only causes of death....