Rat poison kills great horned owl, sickens baby bird at SLO County nature preserve
A great horned owl found dead at Sweet Springs Nature Preserve in Los Osos two months ago was killed by rodenticide poisoning, testing by California Department of Fish and Wildlife found.
Although the adult male owl only suffered a minor cut, the anticoagulant rodenticide caused it to bleed to death in April, the agency said.
Also in April, a baby owl was found on the ground at Sweet Springs in poor condition, and rushed to Pacific Wildlife Center in Morro Bay. A veterinarian suspected rodenticide poisoning, and treated the owlet with vitamin K.
The owlet is now in rehabilitation at Pacific Wildlife Center, where it’s learning how to hunt before it’s released back into the wild.
“If the owl is released back in Sweet Springs and we haven’t addressed where the poison is coming from, then we are releasing into a place that is not safe”, said Judy Neuhauser, president of Morro Coast Audubon Society. Her group has owned and managed Sweet Springs Nature Preserve since 1989.
Morro Coast Audubon Society suspects that the poison may be coming from a nearby mobile home park, where some residents have reported finding dead rodents on their lawns.
The second-generation anticoagulants in the poison are slow acting, which means rats or other rodents will come back and feed over and over again.
“It compromises the rat’s behavior, by causing it to hemorrhage,” said Neuhauser. “They’ll come out looking for water, stumbling around, and attract raptors. When they are eaten by the predators, the predators are now poisoned.”
Wildlife can become very ill or die as a result of eating poisoned rodents, and the rat poison’s effects can last for months.
According to Neuhauser, rodenticides can affect “hawks, eagles, mountain lions, bobcats, coyotes, foxes, skunks ... The list goes on.”
That’s in addition to pet cats and dogs.
“Removing the top predators from any ecosystem then it starts to wreak havoc on the functioning of that ecosystem,” she said. “This will cause explosions of populations of rats and lead to more poison.”
“The poison has also been found in snails, insects, song birds, everything from the bottom of the food web to the top, they are being impacted,” said Lisa Owens-Viani, director of Raptors Are The Solution (RATS), an organization that advocates for safer rat removal alternatives.
In early May, a volunteer with Friends of Griffith Park found a young great horned owl downed on the ground in a Beachwood Canyon residential area after the neighborhood was treated with rat poison bait boxes, Owens-Viani wrote in an email.
The young owl died shortly after being rescued,” she said. A report from UC Davis veterinary medicine confirmed the cause of death to be rodenticide poisoning.
“It’s a pervasive insidious problem, and that’s why we are trying to get the state to pay attention to it,” she said.
The state pulled second-generation anticoagulant rodenticides off of shelves in 2014, and they are no longer commercially available. However, pest control companies still use them to kill rodents such as rats.
“The regulations that took them off consumer shelves left a giant loop hole that allows the industry to keep using them,” said Lisa Owens-Viani. “That’s the loop hole we are trying to close with our proposed legislation.”
With hundreds of losses of predators per year, 21 environmental organizations sent a request to Gov. Gavin Newsom for an emergency moratorium on second-generation anticoagulant rodenticides while the California Department of Pesticide Regulation reevaluates the products as the result of a lawsuit filed by RATS in 2018.
RATS suggest alternatives to pest control such as removing sources of food for rats, keeping dense mats of vegetation away from homes and businesses and plugging any holes that may serve as entry ways. There are also different kinds of traps available for use.
To find out more, visit https://www.raptorsarethesolution.org.