CEDAR RAPIDS - Vandals stoned and beat to death about 50 ducks, including some that were just days old, at the Bever Park Children's Zoo overnight.

A zoo employee discovered the dead birds around 7 a.m. this morning. Some were floating in a pond, and others were piled up near a broken rake.

Dave Smith, the city parks superintendent, said whoever was responsible broke the lock on the front gate to the pen and broke into two of the three night houses where the birds are kept overnight.

They believe at least one person herded the ducks together while someone else did the killing.

"They stoned some to death inside the cage with rocks that were part of the landscape," Smith said. "Some of them ran into the water, which is what they would usually do for safety. Once they got into the pond, they stoned them in the pond."

Caretaker Jennifer Plotz locked the birds up at 6:30 p.m. Tuesday. When she returned this morning, she noticed a plastic tub overturned, and thought raccoons had caused the mess.

Then she saw the door open to the night house. *lo** stained the floors.

"It's just heartbreaking," she said.

Around 100 ducks were part of the exhibit, and 46 that were inside one of the night houses were not harmed. Several different breeds were featured, including redheads, canvasbacks, pintails, mergansers and teals, Smith said.

A snow goose that was in the group was also killed. All of the birds at the zoo are surgically altered when they're very young so that they can't fly away, Smith said.

Police took a report, but Smith said there are no security cameras at the zoo and no evidence was found, aside from a footprint in the mud.

In February, vandals are believed to have set the zoo's hay shed on fire, causing $14,000 in damage. It was a total loss, but no animals were harmed. No one has been charged for that incident.

Smith said this is the worst vandalism he has seen in 23 years as part of the parks department.

"This shouldn't be a part of life," Smith said. "This is just sick."

The duck exhibit will be closed until the dead ducks can be removed and the ponds can be drained and sanitized. It will likely reopen by Saturday, after more ducks are purchased, Smith said.

Smith said the duck killings will impact families attempting to return to a sense of normalcy after flooding devastated the community.

"It's just a sucker punch when we're already down," he said.