Much has been made of the so called 'edge' effect of the Krebs badger dispersal exercise and the resulting 'peturbation' of badgers. Personally speaking, I'm not too bothered about John Bourne's 'edges' - or any other part of his anatomy for that matter - it was what did not happen in the middle of the Krebs' areas which should be of concern. Peturbation, or put simply and not so anthropomorphically, the mixing up of badger social groups thus encouraging territorial scrapping, bite wounding and spread of bTb, is said by some to be the trigger for bTb in cattle.
The answer from the Badger Groups, is to leave well alone. Leave the badgers to their own devices, even letting Tb act as a population depressor and all will be well. This of course is absolute rubbish, as experienced by three of our contributers, all of whom did exactly that, and whose cattle paid the ultimate price. 'All was not well' at all. But Bryan Hill's letter (post below) and our observations of the effect of FMD on the badger (and other wildlife) populations, got us thinking that this 'golden goose' term, 'peturbation', about which many speak, but few understand is a natural phenomenon anyway.
When Dr. Tim Roper, formerly of Sussex University, put night vision cameras into farm buildings in Glos., he found that the badgers were using them as a local Macdonalds. Not one but three 'social groups' were regularly feeding there and sharing feed with cattle. Likewise the experience of Staffordshire farmers, unable to grow or harvest crops on a field adjacent to a wildlife park, sat up one night and watched to see why their grass was flat, and nothing was growing. They counted over eighty badgers trundling along to be fed shed loads of peanuts, for the 'benefit' of a paying public. Eighty ? That's a damn big 'social group'. Prof. Harris from Bristol reckoned about eight was stable, then updated this figure to ten a few years later. Pity nobody told the badgers.
So what of 'peturbation', and what is its effect on bTb?
Logically, even without the 2005 / 2006 drought stress as described by Bryan Hill (below), and depopulation of cattle from thousands of acres in the time of peak feeding for badgers which happened during FMD (see our posts on Rosie Woodroffe's 'Letter from America', below), movement of the population is inevitable. Old badgers will fight with younger males, lose the battle and be turfed out, and younger animals have to find their own 'group' structure to survive. Nothing is set in stone. That combined with very large territories in parts of the UK, and simply not enough pee for the alpha male to scent mark 6 sq. miles every week or so, means overlapping of territories will occur. Likewise feeding opportunities seem to indicate that groups will intermingle if a large and regular food source is available.
So is food source the key? With bTb 'endemic' in UK badgers (thank you Mr. Bradshaw) for sure anything that stirs up and stresses the population forcing movement is bound to have a dramatic effect on the diease, primarily in the badgers, but then spilling out into sentinel cattle and other mammals.
But this is where Trevor Lawson, Bourne, Woodroffe et al differ from the farmers who contribute to this site. Leaving an endemically infected population to fester,in our experience, is not an option. Our cattle are victims of that - even, or especially, within Krebs' areas. But neither is causing the territorial scrapping stress (as we prefer to call 'peturbation') as did the Krebs' badger dispersal trial, cage trapping in general and activist 'opportunities' for release or Tb-takeaways in particular.
Which is why, from the early days of this site we have been pushing for whole sett gassing, to reduce population stress, this preferably with the help of Warick University's PCR to identify badly infected setts, followed by continued removal of 'dispersers' or super excreters, living alone in single hole setts or farm buildings.
That Mr. Hill has described his own 'population mangagement' of a heavily infected area, with such stunning success is a victory for common sense, and the result is a healthy badger population living alongside clean testing cattle. But more importantly, the opportunities for territorial scrapping are gone. There is no perturbation if the whole group is dispatched underground. No 'peturbed' animals searching for lost relatives, and instead encountering vicious opposition.
There is no territorial scrapping, bite wounding and stress induced Tb because the main groups which are left, just quietly spread out.
The problem of Tb infected setts reinfecting incomers is solved too - at least for a time, as decomposing carcasses in a sett appear to prevent immediate recolonisation. But what do we know? Probably not a lot. But certainly more than Bourne and Co. - and we're still learning - mainly because we are prepared to listen.