Recurring rodent risks

IT’S not always appreciated, but birds of prey, including barn owls and red kites, play a key role in controlling the rat and mice population in a natural way, writes Donal Hickey

A pair of barn owls can take up to 25 rodents on a single night, it has been found.

A problem is, however, that useful predators themselves often fall victim to artificial methods used in killing rodents. Poisons put out for these pests can end up in the stomachs of their predators, such as the above- mentioned birds, with fatal consequences.

Many people feel compelled to use rodenticides to deal with infestation, with the aim of protecting human and animal health and avoiding food contamination. The risk of the spread of disease by rodents makes us pretty ruthless and poisons are the most common means of control.

Unfortunately, this can also affect a wide range of other wildlife. Predators are exposed if they feed on rodents which have died from poisoning, or on rodents which have toxins consumed. Evidence of this has been found on the carcases of barn owls and kites. Rodents also form a major part of the diet of pine martens and stoats.

The barn owl population has declined by 50% in the past 25 years. Deaths in road collisions are significant in the drop, but poisoning is also an issue. The barn owl, a silent and highly-effective killer, will only catch live rodents, but poisons can accumulate in its system and eventually kill it.

Kites were reintroduced here between 2007 and 2011 and are breeding, but poisoning is a serious threat. Buzzards can be seen in most parts of the country. They feed on live animals, but also take carrion which puts them at risk. Otters, foxes and hen harriers are exposed in this way.

Similarly, sea eagles released in Killarney National Park have died after consuming poisons which are usually used to kill foxes and crows. Of the 100 eagles set free in the park, 30 have died, the majority from poisoning.

The Campaign for Responsible Rodenticide Use, run by the rodenticide industry in Ireland, has drawn up a code of code of conduct for the use of poisons, which Teagasc is urging farmers, in particular, to comply with.

The code urges better management of poisons and also points to other ways of dealing with problems, — traps, for instance, while not forgetting cats and dogs! Also, people can do a lot to keep out rats and mice by making their property more rodent-proof, and denying access to food, water and shelter.

GLAS, the agri-environmental scheme, says those taking part in the scheme should comply with the code of conduct in their daily farming activities so as to minimise dangers to non-target wildlife.

• www.thinkwildlife.org