No I haven't tried anything yet. I wasn't aware of attractants.. sounds promising. Do you know if the effect lasts very long?
Depends on the type of attractant used.
Some are hormonal and are generally for attracting males as they rely on hormone-female urine sort of thing, a single dose of spray on some brambles or gorse is enough. They generally last a week or two if it doesnt rain, but fades with time. by the end of the second week its very faint, (but a boar will pick it up easy). This stuff will attract males from miles away. Though they arent fooled for long and dont hang around for long if theres nothing to keep them there (like a feeder or the female they were looking for) but if used with the next type they could be enticed to frequent the spot.
I currently have a lone male frequenting a spot where I did this, he has been visiting and rubbing the same tree now for the last six months even though I only used it twice. I once had a sounder of 7 adults hit the same tree on a foggy night as well. They were never back though. The male is now a regular. I like knowing hes around.
Then theres the rub type. Its a tarrish product made from Beech I think or pine resins. Its rubbed on tree trunks or stumps. This is generally more useful as it brings in the whole sounder. This stuff lasts quite a bit is very stinky but will dry out eventually. The boar will generally return to where it was used if they get into the habit of using that particular stump for rubbing. Especially if theres somewhere to wallow or if they generally feel safe being there. (for that to happen you would have to shoot away from the location. So that they dont associate it with danger. Figure out their routes and use that) so use denser areas for that. their tracks in and out will be quite visible making them easy to ambush en route to the rub. (wind is important)
Used in conjunction with trail cameras to give an idea of the times they frequent where the products were applied will help a lot. Especially if you are unable to go there too often.
Then theres used car oil as well but I would strongly advise against that, no matter how effective it is because it is very toxic to the environment and no one likes going into a forest to find a big black patch of oil on the forest floor. the tar product eventually disappear, the car oil will not.
anyway these can be bought off amazon if theres no suppliers in the UK.
https://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=wild+boar+attractant
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I think using a feeder or food in general will work, but is more labour intensive as they eat a lot! and if the food runs out or for some reason you are unable to feed them etc they will move on and may take a while to return. Boar generally travel large distances when foraging and may not return for a month to a particular area if they dont feel the need.