I live above a lake which has a pair of resident swans and on Saturday morning October 6th 2012 a pair of swans with two cygnets not yet able to fly strayed on to the lake from somewhere. The resident pair saw off the intruders after a big fight leaving the two cygnets behind. The resident pair killed the two cygnets. The resident pair have been on the lake for quiet a few years and not even Geese who's territory is some way away never dare come onto the lake.