Marine council wants more info on mice plan


A U.S. Fish and Wildlife plan to eradicate invasive house mice from the South Farallon Islands met opposition and criticism during a meeting of the Gulf of the Farallones National Marine Sanctuary Advisory Council on Wednesday.

The Fish and Wildlife Service, which began scoping for a draft environmental impact statement a few years ago, says that the invasive mice harm the ashy storm petrel population, a species of special concern, and the larger ecosystem on the islands. The draft E.I.S. includes one no-action alternative and two action alternatives that would use rodenticides, either brodifacoum or diphacinone, to eradicate the mice, in several applications. 

Although the service will ultimately choose which action to take, it must obtain roughly 16 permits before pursuing an action alternative, and one of those will most likely need to come from the marine sanctuary. Ann Morkill, a project manager for the service, said the position of the advisory council, which can make recommendations to the sanctuary’s superintendent Maria Brown, “would weigh very much” on agency decisions. 

During the public comment period, concerns were raised about whether or not the federal agency understood the collateral damage of the rodenticides in the long term. Speakers cited the case of Rat Island off Alaska, where 46 bald eagles and over 400 other birds died due to a mismanaged eradication project that involved Island Conservation, which is also a partner in the Farallones project. Ms. Morkill said that Fish and Wildlife was “learning lessons from Rat Island.” 

Susan Kegley, who heads the Pesticide Research Institute in Berkeley and was invited to present on Wednesday, said brodifacoum has “a very long plasma half life” and can take over three weeks to kill small animals, leading to a high risk of secondary poisonings. She voiced serious concerns about impacts to seagulls, which are highly sensitive to brodifacoum. Once the mice were gone, she worried the owls, which are attracted by the mice but also eat the petrel eggs, would eat the adult birds themselves. She asked why the regular physical removal of owls was not a serious option. 

Ms. Kegley also asked how necessary the plan was, given that Fish and Wildlife has declined to list the petrel as an endangered species, and suggested that the D.E.I.S. underestimated the risks of brodifacoum and overestimated the risks of diphacinone.

Sonce Devries, who was the acting national integrated pest management coordinator for Fish and Wildlife Service for two years and worked at the federal agency 22 years, commented that the plan “frankly is unnecessary.” She added that an eradication project could be undertaken in the future if a better way was found.

Representatives of Wildcare and the Environmental Action Committee urged the council not to endorse the action alternatives. “Each creature that consumes this poison, directly or indirectly… will bleed to death, and bleed to death slowly,” said Kelle Kacmarcik of Wildcare. 

The advisory council voted 5-2 for a resolution expressing concerns about the DEIS and requesting more data about potential impacts to sanctuary waters. After the meeting ended, a Fish and Wildlife spokesman, Doug Cordell, said owl relocation would be “endless” and expensive. He said Ms. Kegley overstated harm to gulls based on a misunderstanding of the D.E.I.S., and that the absence of mice would not lead owls to eat petrels because once mice were gone, a time gap would preclude the owls from being there at the same time as the petrels. In general, Mr. Cordell felt that some claims were “factually inaccurate” and others taken out of context. Mr. Cordell and Ms. Kelgey also debated whether or not the ashy storm petrel were in decline or not on the islands.


To learn about the eradication plan and to comment until Dec. 9, visit