Hobsons Bay wildlife rescuers and vets are urging people to use alternatives to rat bait after seeing barn owls and other birds of prey become sick or die from secondary poisoning.

Two birds brought into care in the past week have died after eating vermin that had consumed rat bait.

Donna Dorrington said her father had found a black-shouldered kite at Altona’s Cherry Lake and her cousin found a barn owl in her Spotswood backyard within about a week.

“There’s rat traps and other things that you can do rather than lay out rat bait if you’re close to areas like Cherry Lake that has lots of birds of prey around,” she said.

Hobsons Bay Vet Clinic nurse and birds of prey carer Wendy Black, who could not save the two birds, said very few survived secondary poisoning.

“It’s worse in winter months because I think the mice, as they get cold, they start to go into factories and into people’s homes and so people start baiting,” she said.

“The mice that have eaten the bait leave the homes and then the birds of prey are picking them up and eating them and they’re dying of secondary rat poisoning.”

Western Animal Rescue’s Leanne Kovach said there had been increased numbers of raptors coming in, mostly barn owls.

“Half are starved and the other half are baited,,” she said. “They’re just eating multiple mice that have taken bait.

“Sometimes it kills the animal instantly and other times they get a build up of toxins and it’s enough for them not to be able to feed or get off the ground for a week or two, so they come in thin as well.”

Bird Life Australia and the Department of Environment, Land, Water and Planning have identified rat bait as being the most likely cause of the recent deaths.

The department advises swapping poisonous baits for humane traps or to dispose of poisoned rodents so birds of prey can’t find them.

Injured animals can be reported to a local wildlife rescue or vet, or Wildlife Victoria on 1300 094 535.