From time to time I’m asked to explain the science behind my stance on the cull so I was very excited to find out that Rosie Woodroffe, a specialist on badger ecology, and the only ecologist on the ISG panel (the Independent Scientific Group responsible for advising the government on badger culling), was talking at the Badger Trust conference.
This was a great opportunity to hear the arguments against culling from the country’s (if not the world’s) foremost authority on badger culling as means of preventing Bovine TB.
Rosie was talking at the conference about her involvement with the Randomised Badger Culling Trial (RBCT). The Randomised Badger Culling Trial was carried out by DEFRA in response to repeated calls for culling of badgers, and rising rates of bovine TB. This was the biggest study of it’s kind ever done, before or since. 10,960 badgers were culled at a cost of £40 million and it took 10 years to complete.
Bovine TB hotspot areas were focussed on, as Jim Paice (the minister of state for DEFRA) has recently suggested new badger control measures will be.
There were 10 proactive culling areas – culling every year for five years;
10 reactive culling areas – culling in response to local outbreaks, as per the previous 20 years of DEFRA / MAFF policy;
10 control areas, where no culling was carried out.
Each area covered 100 sq Km, with a circular boundary to reduce boundary effects. Hard natural boundaries were used where possible, but this proved impossible and therefore choice of areas was based on TB levels, and hard natural boundaries were secondary.
Hard natural boundaries is one of the aims Jim Paice believes he can achieve, despite the experience of the ISG.
The effects of culling depended heavily on the ecology of the badger. Badgers are social. Badgers are territorial and badgers are, in the main very unadventurous, and most never leave their own social group… in an undisturbed environment.
As proactive culling was repeated, fewer badgers were captured, suggesting a decline in the population. However, an increase in badgers caught close to the boundary of the study area occurred. Badgers seemed to be immigrating from outside the boundary, and these were then also culled. A 70% reduction in badger population was estimated, but this was probably much lower than the real figure, due to the number of badgers immigrating into the area.
So, what effect did this repeated culling have on badger behaviour? Inside the culling area territorial ranges began to increase, badgers began to range more widely. But, importantly, this also occurred around the edges of the area, outside the boundary. Badger density decreased both inside and outside the culling area, but the remaining badgers began to travel further.
This effect was also seen within the Reactive culling areas, but because this was only carried out in response to outbreaks of TB, very quickly it became clear that the disease was becoming more prevalent in those badgers now ranging more widely. ie despite a reduction in badgers, the % of those badgers remaining, carrying the disease increased. In the reactive areas it was clear, that type of culling not only didn’t work, it made things worse.
In undisturbed badger populations disease does not spread far in space, isolated pockets can remain for years without that changing. Culling breaks down territorial boundaries and increases the number of badgers with the disease. Culling badgers CANNOT contribute to a healthier badger population.
The impact on cattle was as follows; herds inside proactive culling areas showed a 23% reduction new in incidents of confirmed tb, in comparison to the control area, whilst culling was ongoing.
Herds in a 2km belt outside the culling area showed an increase in confirmed incidents of tb of 25%. Inside the culling area, fewer badgers with a higher likelihood of the disease were ranging more widely, but fortunately it seems, there were not enough of them to cause an increase in the disease. Outside, there were more badgers, causing an increase in the disease in both the cattle and the badgers.
It looked, for a short time as though there were benefits both inside and outside the Proactive culling areas, 6 months after the culling stopped, but they were not statistically significant. It is thought that the badgers began to recover their behaviour and their territories stabilised once more, reducing the effects of the disturbance. But remember, there were fewer badger numbers in those areas, we don’t know what will happen over time when badger numbers increase to pre-cull levels. In a population with a now higher % of the disease. 48 months on, it appears that the small benefits to cattle may last another year, perhaps then the tide will turn. Proactive culling seems like a simple extension of reactive culling to me, what if after the minimal initial drop, we get an increase?
Aside from that, the cost of culling badgers is massive. To prevent 17 herd breakdowns inside a culling area of 150km sq in a perfect circle, you would prompt 12 breakdowns on neighbouring land. 5 less breakdowns, saving £143,000. To break even, benefits of culling would have to last for 12.5 years, not the currently projected 5.
WAG tried to improve on this with areas of 288km sq. They tried to find areas that were geographically isolated, with hard physical boundaries, in order to reduce the effects of badger migration. Unfortunately those areas tend not to have high rates of tb in cattle, so instead they concentrated on areas with high tb. How is Jim Paice going to do any better?
They calculated a 9% reduction in tb, using the RBCT figures. But they neglected to take into account two important facts;
- the RBCT caused a relative reduction in tb (a non significant one as stated previously), not an absolute reduction. ie a reduction in the increase over time of tb, it rises more slowly. So something else must be causing the background rise in bovine tb.
- Culling also only reduced the incidence of confirmed tb ie. tb confirmed at post mortem. It did not have any affect on unconfirmed herd breakdowns. Confirmed breakdowns make up 2/3 of all breakdowns.
WAG couldn’t hope to achieve even the 9% reduction they calculated through culling.
In England, the government has cancelled the majority of the field tests of badger vaccination, no reason other than cost has been given. But sources have stated that they are beginning to show promising results, without any of the perturbation effects, or, for the people in this country that value their wildlife, any culling.
The government seems so far to be suggesting that farmers should pay for culling themselves, and licences issued to groups of farmers. They would need to work together over 141 square km for a minimum of 5 years. During the RBCT 13% of landowners proved uncontactable, and even where landowners are contactable, all of the landowners would have to agree to a cull. To achieve what they would need to achieve (bearing in mind that no-one knows yet what the longer term effects will be anyway), they will need to cull where there is opposition. They will need permission for all the land. They will need hard boundaries around all of the culling areas. Neighbours will see an increase in tb and opposition will increase. There is a serious risk of increasing the spatial and % incidence of infection.
Can the farmers really do this? Realistically, no. If DEFRA couldn’t, small groups of farmers cannot do better. The RBCT study took into account effects of interference by animal rights activists and opponents during the study, but despite short term interference this did not affect the overall numbers of badgers culled. Yet this is often an argument used to discredit the science. Another is the perceived too low numbers of badgers culled; unrealistically, some farmers believe that all the badgers in an area can be removed. This is not the case. In fact, increasing the number of badgers killed would have no effects on the results, due to movement into the area by badgers from outside. In fact, this is likely to make the situation worse on the boundaries by reducing the density of badgers and increasing movement further and further from the culling area.
The RBCT was the biggest, most thorough study of its kind ever done, and culling badgers has not been proven to work and furthermore is not economically viable as a preventative measure.
Jim Paice wants to implement cattle measures and culling. Surely the place to start is in the cattle measures, at the very least until we know what the long term effects of culling are. For the sake of the farming industry itself!
In summary;
- culling badgers increases the prevalence of the disease in the badger population (and legally, to reduce the spread of disease, that is the ONLY reason a licence can be issued).
- No-one yet knows what the effect of long term proactive culling will have on herd breakdowns. It may still have made the situation worse.
- Something else (besides badgers) is causing the increase in tb – which actually has recently begun to slow.
- Achieving hard boundaries and culling an area large enough to be financially efficient is going to be impossible, particularly for farmers to achieve themselves.
- Vaccination, as an alternative, was showing promising results, and does not create any perturbation in the badger population.
- Vaccination would in time reduce the % of disease within the badger population, unlike culling – the reason the increases have occurred is in part due to the culling carried out over the last 20 years.
When she concluded her presentation Rosie said something that resonated strongly with me and everyone involved with the Badger Trust; she said that she had the lives of 10,960 badgers on her conscience and the only way that she could live with that was if the science, which in my opinion was great, was used to prevent the needless slaughter of more badgers in the pursuit of precisely the kind of wrong-headed policies that have contributed to the worsening situation over the past thirty years and that Jim Paice is stubbornly putting forward today.
We all have those badgers on our consciences and we must do everything we can to make sure that the lessons learned from the RBCT are not lost and that those badgers did not die in vain.