I've had the usual encounters with rats, mink, squitzels, snakes, badgers, foxes, deer, owls and the like, none of which have spoilt my day (or night) - quite the opposite, as I regard their presence as a sign I have been accepted into their domain. Ducks, geese, swans, coots and seagulls on the other hand have ruined many a session. The gulls take your baits as you fire them out, the coots and tufties pick up what little gets past the gulls off the bottom (and unhooking a coot is no fun, believe me). The swans chase the geese, the geese climb into your bivvy to get away from the swans and poo all over your sleeping bag, and the whole lot of 'em continually search out and destroy carefully-laid lines.
However, all of these pale into insignificance compared to my worst bankside enemy - cattle; sub-species bovine, male. I've been driven from more good barbel and chub swims than I care to count by the antics of these blasted things. One memorable afternoon I'd dearly love to forget involved walking backwards through two flooded and extremely treacherous fields, waving a landing net at half a dozen fully-grown bullocks intent on re-enacting Riverdance on my fragmented remains.
The net waving trick was a tip from another angler (strangely absent on that day) which, I can confidently say, didn't work. Nor did prodding them with the handle, shouting, arm waving or any number of other undignified strategies. I stopped short of trying BB's advice to 'roll around on the ground and make uncouth noises' - not because there was anyone looking, but because it was very wet, and I figured I was best served by remaining at least partially above the marauding beggars.
Of course, not all cattle are bad, but I am in complete agreement with Arthur Ransome, who declared that 'it is difficult to ascertain whether the cattle in question are good or bad without inviting so close an acquaintanship that the situation is difficult to remedy should they turn out not to be good ones.'