Tests being carried out on carcasses of native red deer in Killarney National Park

Tests are being carried out on the carcasses of native red deer in Killarney to determine the root cause of a distressing condition that has come to light during the current rutting season.

A number of animals including young stags and female reds have been spotted with severe imbalance and appearing to stagger, while some have deformed antlers.

The condition appears to be limited to an isolated area of Killarney National Park and a small number of the animals affected have been culled by wildlife rangers.

The carcasses have been sent for testing to a Department of Agriculture laboratory, it is understood.

The Irish Deer Commission had called on the National Wildlife Service to carry out culls of the affected animal on animal welfare grounds, and to identify exactly the cause.

Two weekends ago a young red stag on the fringes of a rut walk organised by the Irish Deer Commission and the National Parks was observed stumbling and in a distressed condition.

The IDC suspects the animals are suffering from “staggers” which affects deer and other animals affected by toxins from fungus on ryegrass.

So far only the native red deer appear to have been affected. The park's 700 Sika deer, introduced in the nineteenth century, are not showing symptoms.

"The condition has shown in young male deer and females with no evidence of symptoms in mature stags. Prior to the rut, female deer and young males tend to feed in the same area, with mature stags forming bachelor herds and feeding in different areas," Damien Hannigan of the Irish Deer Commission said.

While the cause of the symptoms is unknown and subject to further tests, the symptoms are consistent with Perennial Ryegrass Staggers, a poisoning by peramine, lolitrem B, and other toxins that are contained in perennial ryegrass and produced by the endophyte fungus Neotyphodium lolii.