Otters and ducks

In an earlier post I wrote that “there seem to be have been very few ducks for some time on the Kennet & Avon Canal which runs through our village. An impromptu conversation with a barge resident in the village shop told me something I didn’t know – otters eat ducks, and perhaps they are doing rather well on that stretch of water. I was also told that that would be in spite of the best efforts of some local fisherman who leave out fish laced with poison to try to eradicate them.”  Thinking back to that conversation, a couple of parts of it didn’t sound right to me.  I’ve realised that one of my real pet hates is people who speak with great authority on subjects they know nothing or little about.  I am sure this guy was simply repeating something he had heard, it’s when someone asks me a question about bookselling, for example, then refuses to believe what I try to explain because they think they know better, that I find galling.  I’ve been bookselling for over 40 years, so there’s a chance I might know a little bit about it.  One suggestion was that the reason otters in the canal eat ducks is because they are the wrong sort of otters, reintroduced.  These, I was told, were European otters, as opposed to good old British ones.  Which does not sound to me very far from “Those awful foreign otters, coming over here and eating all our patriotic ducks.”  Dietary variation between closely related but different species is not that unlikely in itself, but I suspected that all otters eat ducks if any of them do.  In any case, ‘our’ otters are Eurasian, the same species found all over Europe and elsewhere.  The second suggestion was that whilst anglers leaving out poisoned fish worked on minks, it didn’t work with otters because they only eat the heads of fish and leave the rest, so do not ingest sufficient poison to kill them.   I checked this with a friend who has a tendency to come up with information about wildlife which does not always prove correct.  I wish these people would just say “I don’t know” or “I am not sure”.  He confirmed the fish head theory, but of course it is nonsense.  Otters commonly start with the head and sometimes discard the tail.  That’s it.