Teamwork needed to win fight against rabbit menace
18 September 1998
Teamwork needed to win fight against rabbit menace
Waging war on the
growing rabbit population
demands a team effort to
achieve any real success.
Andrew Blake reports
PIECEMEAL rabbit control measures are doomed to failure; that is the stark message from a specialist consultant with over 20 years experience of the pests.
For long-term effective rabbit control, co-operation and properly tailored strategies are essential, says Roger Trout, long-time MAFF researcher now running his own firm Rabbit-Wise.
Rabbits cost cereal growers alone about £40m a year, according to the Central Science Laboratory. One rabbit a hectare equates to about a 1% loss in yield in winter wheat. So in a 6.5t/ha (2.6t/acre) crop each pest loses 65kg of grain, which at £80/t is worth £5.20.
In the early 1990s the overall cost of rabbit damage was put at £120m, notes Dr Trout. Since then the UK rabbit population has continued to grow and in places in England and Scotland has reached pre-myxomatosis levels. "For each rabbit you see there up to four you do not. Each doe may have six litters of five young each year, though the average total is nearer 20.
"With farm incomes dropping, the damage rabbits can cause could make the difference between profit and loss in some cases. Clearing and fencing new plantations has also considerably altered the costings of forestry recently.
"Farmers often pay large sums a hectare for pesticides, sometimes even if there is no evidence of damage. Suggest the same amount for rabbit control and you usually get a look of horror. But some have spent £10,000 on fencing in one year and recovered the cost in two."
Clearly specific enterprises can justify spending more, says Dr Trout. "A rose nursery, where one rabbit bite can render a £15 plant valueless, has much more at stake than a moorland enterprise." Myxomatosis, introduced into the UK in the 1950s at first killed 99.9% of all rabbits that caught it. "Now it kills only about 20% because of weaker strains and because genetic resistance has developed."
Viral haemorrhagic disease, which proved very effective in winding down Australian rabbit numbers, was notifiable in the UK from 1992-96 and was first found in wild populations here in 1994. But though information is scarce, some UK rabbits, especially further north, already appear immune. So although it may help, growers should regard it as merely another aid to control, says Dr Trout.
"Few farmers realise there are over 30 different management options available. Using the correct combination at the right time of year is vital. Too often farms and estates rely on people coming in occasionally to do a bit of ferreting or shooting. That palpably has less effect than a well planned strategy and at best only holds the problem."
November to February, before the main breeding season, is the best time to launch the war, he says. "Every doe controlled then means about 20 not born the next season." A common mistake is to concentrate all ones efforts on so-called hot spots. That simply leaves a vacuum which soon sucks in the pests from surrounding areas.
Tackling rabbits successfully requires a co-ordinated approach involving as many neighbours as possible, he advises. "Rabbit clearance societies once performed this role. But most have since become defunct, primarily because the centralised funding base and strategic planning was too weak." *
BUNNY BATTLE
• Rabbit numbers rising.
• Damage increasing.
• Piecemeal control futile.
• Co-operation essential.
Systematic approach stops it getting out of hand in Scotland
One region determined to get rid of rabbits in a systematic way is the Nithsdale Valley in Dumfriesshire. It has recently formed a control society after an SAC study suggested the pests cost the 400sq km region about £0.75m last year, mainly through loss of grazing but also in cereals and forestry. The mainly light sandy soils of the river Nith valley provide ideal rabbit breeding conditions.
"We saw that the situation was getting out of hand," says one of the co-ordinators, Andrew Bruce Wootton, assistant factor on the Buccleuch Estates. "With margins tightening, rabbit damage was really beginning to eat into profits. But we realised that unless everybody co-operated our own efforts of control could have been a complete waste of time."
Since spring the main drive has been to devise a co-ordinated control strategy and draw together the community by promoting membership. "We have had a tremendous response and now have strong support from local agricultural and forestry business together with public and environmental organisations." With the help of Dr Trout, initial control tactics focussing on permanent netting with live capture box traps are already being planned for this winter. Gassing, shooting and other conventional methods will follow.