I do sympathise with you, Ann, about the hogs turning up with marks on them. A similar thing has happened here.
I have been watching and looking out for the hogs here for many years and can identify most of them by their natural markings. Recently, old friends have begun to arrive with graffiti on them – very sad to see. One of them must have had at least half of his spines covered with some unknown substance. Others have had stuff on their faces and around their eyes (possibly as a result of biffing another marked hog). But also commonly on their skirts, which is worse than being on their spines, because it would be so easy for them to ingest whatever it is. Sometimes the hog is marked in such a way that their natural markings and colouring are hidden.
But, my worry is that it may go further than that. Hedgehogs rely heavily on their sense of smell and I am concerned that the excessive marking which is happening could impact on their social interactions.
This year, for the first time, when excessive marking has increased, I have seen much more ferocious fighting than has been usual. Previously I had identified a sort of pecking order and the less dominant male usually just got rolled up and perhaps biffed and pushed around a bit. It could be a coincidence that the ferocious fights have always included at least one excessively marked male, but perhaps not. Perhaps the hogs are not recognising each other, due to the quantities of foreign substance on at least one of them.
Excessive marking could also impact the females. If a female doesn’t smell ‘right’ is the male going to persevere to mating? They may begin the courtship ‘dance’ but give up too soon. There have been several mature females about, and many ‘dances’ took place earlier in the year, but only 3, hoglets (probably all from the same litter) resulted.
It would be difficult to prove either way, but with hedgehog numbers as they are, is it a risk anyone really wants to take?
Personally, I see no need to mark hogs at all, unless it is for a properly organised scientific study for the benefit of hedgehogs. My feeling is that any interaction with a hedghog, should only take place if it is for the benefit of the hedgehog, or hedgehogs in general.
I believe that hedgehogs deserve live their lives in peace in their wild, natural, beauty.