After a colder than average winter, everyone seems to think that this year?s rat problems will be less severe than usual. If an animal such as a rat is on a knife edge in terms of getting enough food, then I suppose a combination of hunger and cold might cause it to succumb. However, cold alone is hardly likely to kill them if they have enough food.

So, as gamekeepers have stepped up feeding programmes to help game through a difficult winter, the rats will surely have been helping themselves, too. A look around my beat, as I filled the feeders last week, showed several sites where there is a rat problem to address.

My involvement in helping to deliver the Campaign Against Accidental and Illegal Poisoning over the past three years has made me aware of the spotlight that shines on rat control by gamekeepers. Low-level rodenticide residues in a wide range of wildlife is a big issue, and much of the pest control industry sees gamekeepers as a key source of this.

Over the past decade or so, quite large samples of a wide range of predators have been analysed for rodenticide residues. These studies have shown that high percentages of some species carry low levels of these chemicals. Red kites, for instance, have shown up to 70 per cent contamination. You might put this down to their being a carrion feeder and picking up dead rats, but up to 65 per cent contamination of kestrels is not so easy to explain. Nor is a figure of around 40 per cent in foxes and polecats or 30 per cent in weasels.

Contamination control

This is not to suggest that these animals contain high levels of these poisons ? most of this is at a low level, and far from life threatening. However, any contamination of this sort is undesirable. Shooting Times?s readers with long memories will be only too aware of the history of organochlorine pesticides and the damage they did to birds of prey further up the food chain.

How does this secondary poisoning happen? In a way, that surprising figure for kestrels may be a clue. Rather than target animals being picked up when they are dead or dying, the current consensus is that the main route to our predators, such as kestrels, is through non-targets such as mice and voles. These, in turn, really only get access to rodenticides in the countryside, rather than in and around buildings. And who uses these chemicals in the countryside? Gamekeepers, of course.

All of this is overly simplistic, and I would be the last person to point an accusing finger at the gamekeeping profession. In truth, there are lots of other people using anticoagulants in the countryside, too. However, anything that keepers can do to minimise exposure of non-targets to rat baits must be a good thing.

Rat action plan

So, here is my four-point plan for rat control on my own shoot, which I hope provides some useful ideas. The first part is keeping the rats where they belong and not letting them get out of hand. Making rat control part of the annual plan, even when there are few, will keep things that way and mean that the amount of bait that you need to use is kept low, as well.

Second, a few tunnel traps in key places where you can easily check them every day can account for a lot of rats and help you to achieve point one. Also, every rat that you kill this way is one less dose of bait that you need to buy. My third part to the plan is to gas wherever possible, and here is another worry: I gather that the use of phosphine pellets may be under threat from the 2009 EU directive on sustainable use of pesticides, so we may need to mobilise over this issue, too. Again, rats killed in this way mean doses of bait are saved.

The fourth part of the plan is to keep the anticoagulant as safe as possible. For me, this means mainly burrow baiting. By putting it only into active rat holes, and lightly burying it with soil, it is out of reach of those all important non-target species. I follow this up with frequent visits to all sites, topping up where holes have been reopened and tidying up any bodies. The latter rarely happens, as they all seem to die underground, safely out of reach of scavengers.

If all this is new to you, can I make two suggestions? First, please read and follow the instructions on the label of the rodenticide. Second, book some training. Even if you have the certificates from college, there is much that is new and gamekeepers need to demonstrate their professionalism by being trained and up to date.