A court held three times each year before the forest verderers. This court had nothing to do with the birds, the swans; rather, the jurymen were swains employed in the forest, i.e. herdsmen. It was established under the *Forest Charter of 1217, whose purpose was to oversee the pasturing of pigs and cattle in the king's forests; also ensuring animals were cleared at times when they might interfere with the forest's life, e.g. during fawning and the hunting season.
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.