I live on an inland lake in Michigan, and have enjoyed watching many swan families evolve from the same cob and pen couple. This year the pair had five cygnets that were reduced to three fairly early. We suspect a local bald eagle because they moved the remaining cygnets to dense tree and brush cover. One evening back at the end of July people were still shooting off fire works periodically (nothing like the week of the fourth) when the parents cornered one of the three remaining cygnets and pecked it to death. Last week the same thing happened on my parent's small and very quiet fishing lake. Out of the blue, the cob chased down and pecked to death, one of their almost full sized young. I have lived on my lake for 23 years and have never seen or heard of this behavior, and now, twice in one year. Thanks for any info. Denise Klein