On Monday afternoon, a team at the Wetlands and Wildlife Care Center in Huntington Beach took in more sick mallard ducks and a snowy egret.
"They can't stand. They're not able to fly," said wildlife technician Sheila Eberly.
Over the past week, park officials say 25 sick birds - mainly mallards - have been rescued from Laguna Niguel Regional Park. More than 130 have been found dead.
"They're not able to hold their heads up, so there's signs of botulism, but it's not confirmed," said park ranger Carroll Baldwin.
Experts say possible botulism poisoning could be due to people feeding the birds, even though signs clearly warn people not to.
"When (the bread) goes into the lake, it becomes laden with bacteria, and then the birds eat it, and they get what they call a limber neck disease where they can't raise their head," Baldwin said.
At the Wildlife Care Center, workers are giving the sick birds fluids to try to flush out the toxin, which is slowly paralyzing the birds' muscles.
"When they first come in, they're on an hourly tubing schedule," Eberly said.
Authorities are awaiting test results to determine what is making the birds sick.