News

Is the Rare Golden Plover A New Tick Victim?

July 2004

It might be small, but the tiny spider-like tick packs a powerful punch and its population is on the increase. But it’s not just humans that are affected by this growing problem, many wildlife species are either succumbing to diseases transmitted by the blood sucking tick or are simply dying through the impact of ‘tick worry’ caused by the sheer numbers feeding upon one host.

New research by The Game Conservancy Trust has identified a further potential tick problem. It seems that important populations of moorland breeding wader birds, particularly the rare golden plover, might also be suffering from the impact of an increasing tick population and the pathogens they transmit.

In humans an infected tick can cause a protozoal infection called Lyme disease, which is a debilitating illness that can last for many years. In wildlife the tick can transmit louping ill which is mainly a disease of sheep, although other domestic animals such as cattle, horses, pigs, goats and dogs can also be affected.

Since the early 1980’s The Game Conservancy Trust has been studying the impact of sheep ticks and the disease louping ill on red grouse in Scotland. Research has shown that this serious viral disease can kill up to 80% of red grouse chicks infected. Trust scientists have also found that ticks are on the increase in Scotland due to the growth in host numbers such as red deer. It is thought that warmer winters could also be triggering increased tick activity. In 1985, around 4% of grouse chicks encountered by Trust researchers had ticks, but by 2003 the figure had risen to 92%.

On the North Yorkshire Moors National Park in England, anecdotal reports by ornithologists and gamekeepers suggested that it was not just grouse that were susceptible to tick attack. It seemed that moorland breeding waders, such as lapwing, golden plover and curlew might also be at risk, either through the weight of numbers on one bird or through disease.

Dave Newborn, one of the Trust’s scientists in charge of a new preliminary study said, “The North Yorkshire Moors National Park provides essential breeding habitats for nationally important numbers of wader birds. Through previous research we know that tick-born diseases such as louping ill reduce the breeding success of red grouse, and so it is very possible that ground-nesting wader birds sharing the same habitat might also be susceptible to ticks and tick-borne diseases. We need to identify the extent of the problem so that positive action can be taken to protect these birds.”

This important one year study was instigated and is being funded jointly by North York Moors Moorland Association members and the North York Moors National Park. In the past few years, a successful scheme of treating sheep, one of the major tick hosts, with tick-killing pesticides (acaricides), plus the use of vaccines against louping ill has been undertaken by graziers to reduce tick populations and the diseases they transmit.
However, rigorous tick control programmes are expensive and therefore in certain areas, sporting estates with a grouse interest have been helping graziers with funding in order to reduce the incidence of louping ill in the moorland environment and especially amongst the grouse population.

George Winn-Darley, a key Moorland Association member and grouse moor owner explains the importance of this new moorland study. "The North York Moors have been awarded the highest EU bird designation, SPA due to internationally important breeding populations of Merlin (our smallest raptor) and Golden Plover. Moorland owners have a strong responsibility to protect these populations as well as maintaining the moors for the valuable heather habitat and other uses such as grazing, walking and the economic driver - grouse shooting. We know that grouse and sheep suffer from ticks and especially the louping ill virus they carry. It seems probable that the ticks are also having a lethal impact on the Merlin and Golden Plover. Moor owners are delighted to support the study and look forward to its results."

Dave Newborn says, “We have been radio-tracking the waders to measure the extent of the problem and have found wader chicks as young as 3 weeks old with heavy tick burdens. Through blood sampling, we hope to identify if they have become infected with the louping ill virus. As this is an essential breeding habitat for waders any potential reduction in their breeding success needs to be investigated.

“The Trust is interested in all aspects of moorland management. And if our research shows that wader populations, particularly the rare golden plover are at risk, then our study will help to support more funding to suppress the tick population.”
END
Notes To Editors
The Game Conservancy Trust is an independent wildlife conservation charity which carries out research into game, associated species and habitats. In 2003 the Trust spent £3 million in furtherance of its charitable objects of which £2 million was spent on research that is carried out by 60 scientists based at Fordingbridge, and at study centres throughout the country. The Trust’s main areas of interest include farmland, moorland and woodland conservation, river and habitat restoration, disease, predation control and education. The Trust is also responsible for a number of Government Biodiversity Action Plan species and is lead partner for brown hare, grey partridge and joint lead partner for black grouse. Morag Walker – Press Officer Telephone – 01425-652381 (direct 01425-651000) Mobile – 07736-124097 www.gct.org.uk