I’ve been thinking about the badgers at the sett, and how there seem to be much fewer of them than in previous years. I’ve been rolling a plan around in my mind that may help me to understand what’s been going on. Bear with me, and I’ll try to explain my train of thought.
1. The number of badgers has reduced. This means either a number of badgers have died or they have left the sett.
2. If they have died, this could be due to coincidence (i.e. they all died of old age or unrelated accidents) or due to some catastrophe (disease, interference etc). I need to have a look round the sett for bodies, but there is always the chance that if they died they did so underground and I might never find any remains.
3. Based on the work of Hans Kruuk, if they left the sett then they are unlikely to have gone far. Kruuk found that badgers leaving the clan only went to neighbouring clans, no further. There won’t have been a long-distance ‘Watership Down’ style exodus.
Following me so far…?
4. So, by monitoring numbers at the neighbouring setts I should be able to get a better idea of what has happened at the main sett.
In other words…
5. If the numbers of adult badgers at the neighbouring setts have increased significantly, this will suggest that badgers from the main sett have left and migrated there (although it wouldn’t prove it).
If the numbers in the neighbouring setts have decreased significantly, it will suggest that some sort of wide-ranging mortality has affected badgers in the area.
If the numbers have stayed the same it will suggest that no major migration has occurred and the reason the badgers in the main sett have decreased is due to death.
Now, the logic of this seems pretty sound to me. It won’t give definite proof (how do I account for migration to and from the next setts in the chain?), but it may help guide me in the right direction. However, there is one major and probably fatal flaw in putting the idea into practice: I don’t actually know the number of badgers in all the neighbouring setts, either last year or this year. This means that I don’t know whether the population has changed or not. The sett to the west of the main one is the Pine Tree sett. This had one badger in residence last year, so a big increase in numbers here will imply migration.
The sett to the east of the main sett is about 500 metres away as the badger runs. Let’s call it the Beech Tree sett, after the vast and ancient specimen of that species nearby. I’ve known of the existence of this sett for a while (I found it through mapping badger latrine sites) but I’ve never actually sat and watched it.
This evening I decided to have a look at it. I wouldn’t be able to tell whether the number of badgers had increased or decreased, but the sooner I get some data the sooner I can start to build up a picture of the population in the area. I arrived at 7.45pm and watched until 9.20pm, but I saw no badgers at all. I may have arrived too late or disturbed them somehow. In an ideal world I’d have surveyed the site properly in the winter before the bracken grew up so I knew the location of all the holes and could get a rough idea of how many were active. I was lazy – I didn’t do this. I may have been watching the wrong part of the sett for all I knew.
So I’m no further on in my thinking at the moment. I’ll try to get back to the Beech Tree sett again soon and also to the Pine Tree sett, and see if I have more luck.
As a consolation, as I walked home down the pasture field a badger came bouncing up the path towards me, saw me, and dashed off. In years gone by I’d have been happy just to see a badger going about its business. Tonight though I found myself wondering which sett it had come from. I’ve gone from wanting to see badgers to trying to work out the population dynamics of the whole area. Perhaps I’m taking all this too seriously. Perhaps I need to lighten up a little. After all, a day when you see a badger in the wild can’t be an altogether bad day.