Monday, January 27, 2014

Falling off the edge?

This week, the journal Nature, published the result of the latest badger census, - [link] which showed an increase of over 100 per cent in main setts. This is not to be confused with the controversial head count last year, when teams from the same agencies changed the numbers a couple of times and Owen Paterson blamed the badgers for 'changing the goalposts'..

In this census, only main setts or 'dens' were counted, with authors reserving the right to 'further research' before commenting on their occupancy. From the report:
"While badger sett surveys are well suited to estimating the abundance of social groups, on their own they are limited in their suitability for estimating populations of individual animals. This is principally because sett characteristics are a poor predictor of badger numbers, and group size can vary widely making it difficult to obtain a representative mean across an adequate sample. We are currently undertaking work to estimate group sizes across a large sample of setts in order to estimate badger population size".
No, we couldn't work that one out either. Particularly as the same agencies trousered £3.17m for counting badger heads and paws prior to those pilot culls; a task which they now describe sett side, as 'limited' in ability to estimate its occupants.
 Since the early 1980s the accepted formula for counting badgers has been an average of 6/8 adults per main sett, updated to 8/10 adults as populations expanded in the 1980s.

Exploring more of this paper,  Farmers Guardian - [ link ] has some snippets and comments and few more from the paper, we highlight below:
"The implications of increasing badger populations are numerous.

Badgers are the largest terrestrial carnivore in the British Isles. They feed across numerous trophic levels, and largely eat soil invertebrates, but will also prey upon ground nesting birds, hedgehogs and other vertebrates. Evaluation of the ecological impact of badger culling during the Randomised Badger Culling Trial identified an increase in fox abundance associated with reductions in badger density while reciprocal relationships between hedgehog [] and badger distributions suggest that increasing badger numbers might have had a negative impact on hedgehogs."
I think we get the picture. Too many badgers = not much of anything else? Including the 'iconic' hedgehog. Although whether those 'ecological surveys' conducted for the RBCT  by a graduate standing for 4 minutes on a red X within 1000 acres, once a year, achieved anything at all - is debatable,

We are also, thanks to the RBCT Badger Dispersal Trial very well aware of the danger of shattering TB infected social groups, especially when the infection level of such groups in areas of endemic tuberculosis is typically around '43 per cent'. (quote: Mark Chambers - FERA)

But typically, this paper concludes:
"In terms of tuberculosis epidemiology, at a local level, disease prevalence and incidence appears to vary with mobility among groups and prevalence has been shown to be higher in smaller social groups. Consequently, despite a broad landscape scale correlation between the incidence of TB in cattle and the distribution of badgers, badger social group density alone may not predict patterns of TB infection in badgers or cattle."
But it's not just cattle, however much Defra and its quangoes would like to pigeonhole zTB to that end. After all, we're told often enough that cattle get killed anyway." - [link] But last December, that myth was well and truly busted with the publication of Defra tables which may be a tad more accurate than their previous efforts, which deliberately listed the single confirming sample.

Thus 'bovine' TB is no longer a 'bovine' problem', - [link]  but a problem for many grazing mammals and sadly,  their owners too.

But what does that 103 per cent increase in badger main setts actually  mean for their English inhabitants?

 Apart from an indication of the success of their voracious and high profile protectors, the level of disease (quoted by FERA) in these animals is quite shocking. But more than that, where are they expected to live?

They can't sit on each others' shoulders. They have to go somewhere. But to find them gazing out to sea from a Cornish beach is unusual to say the least.

The 'Nature' report concludes:
" Nonetheless, our survey represents a robust, national-scale assessment of badger social group abundance in 2013. It is comparable in approach to those based on sett surveys conducted in 1985–88 and 1994–97 and so is the best, and probably only, basis on which to assess badger population change at the national scale."
And the survey reported a doubling of main setts. And from our picture above, taken on a Cornish beach last weekend, one could assume, that there are so many badgers now that they are falling off the edge of our overcrowded island. A victim of their protectors' success.

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