The RSPCA is seeking information about alleged animal cruelty at a popular Perth park after residents reported a cygnet had been bashed to death by thugs.
The cygnet and its sibling had been delighting visitors to Claisebrook Lake in East Perth for weeks.
But in the early hours of January 27, the young black swan's life was snuffed out.
Photographer Keith Lightbody, who has long been capturing images of the lake's bird life, said residents, workers and council staff were extremely upset by the news.
"Those cygnets were gorgeous," he told AAP.
"They were almost ready to move out onto the Swan River.
"People come down there and bring their kids and grandkids to watch them.
"Tragic that somebody would kill a defenceless, flightless cygnet on the Australia Day long weekend."
Residents have hung a sign on a fence at the lake that reads: "In memory of the beautiful cygnet that was brutally killed by a group of thugs around 3.30am 27 January 2014. Thanks for all the joy you gave us since you hatched. We are so distressed about what has happened. (If you have any information about this heinous act of cruelty, please call Crime Stoppers: 1800 333 000)."
The RSPCA called for witnesses or anyone with information about the attack to contact them on 9209 9300.
The black swan is Western Australia's bird emblem and features on the state's flag.