Three species removed, mouse remains listed under ESA

By Emily Ronis

A lesser long-known bat drinks nectar from a feeder set out by citizen scientists in Arizon to monitor the bat’s migration pattern. ©BLM New Mexico

The U.S. Fish and Wildlife Service issued a final rule last week declaring that the lesser long-nosed bat (Leptonycteris yerbabuenae) is no longer threatened with extinction and can be removed from the endangered species list. This is the first bat species threatened with extinction to be removed due to recovery.

The lesser long-nosed bat was first listed as endangered in 1988. One of three bat species in the United States that feed on nectar, the lesser long-nosed bat migrates from southern Mexico to Arizona, feeding on agave and cactus nectar and roosting in caves. Human disturbance historically contributed to population declines, with the species having fewer than an estimated 1,000 individuals and 14 known roosts when it was listed.

Now the species is estimated to have more than 200,000 individuals and is no longer in danger of extinction, according to the USFWS. The Service says the bat’s recovery is due to cooperation between researchers in the U.S. and Mexico, citizen scientists in Arizona and producers in Mexico who cultivate agave to make tequila.

Arizona residents volunteered to monitor night-time bat use of hummingbird feeders to provide data on the bat’s migration patterns. Tequila producers, recognizing the bat’s role as an agave pollinator, implemented cultivation practices to increase agave nectar availability for the bats.

The rule will take effect May 18.

The USFWS has also determined that the Kirtland’s warbler (Setophaga kirtlandii), listed as endangered since 1973, has recovered and can be removed from the list.

Nest parasitism by brown-headed cowbirds (Molothrus ater) was a major factor in the warbler’s decline. In recent decades, cowbirds have moved into the Kirtland’s warbler’s Jack pine habitat in Michigan and Wisconsin, as expanding agriculture reduced the cowbird’s preferred grassland habitat. Cowbird females will replace a warbler egg with one of their own to be raised by the warbler. The remaining warbler chicks often die as a result. The USFWS implemented an ongoing cowbird trapping program in 1972 to counter the cowbirds’ parasitism.

Now population estimates put the warbler at 2,300 pairs, more than double the recovery goal.

“Without a doubt, recovery is the result of a cooperation among states, local residents, federal agencies and conservation groups,” said Tom Melius, Midwest regional director for the USFWS, in a press release. “This dedicated conservation community is committed to addressing the needs of the Kirtland’s warbler in the future.”

Another bird, the black-capped vireo (Vireo atricapilla), has also recovered and will be removed the endangered species list next month.

Also threatened by brown-headed cowbird nest parasitism and loss of its habitat, the vireo was listed as endangered in the 1987 when only 350 birds were thought to exist.

Now, there are more than an estimated 14,000 birds across the vireo’s breeding range of Oklahoma, Texas and Mexico. The USFWS credits partnerships between states, non-governmental organizations, the military and government agencies with its recovery.

“The black-capped vireo is a success story that shows the power of conservation partnerships,” said J.D. Strong, director of the Oklahoma Department of Wildlife Conservation in a news release. “Now our challenge is to redouble efforts to make sure those partnerships continue — along with valuable habitat restoration work and research — so that vireos and Oklahoma’s other fish and wildlife populations remain healthy.”

Alongside the recovery success stories, USFWS found the Preble’s meadow jumping mouse (Zapus hudsonius preblei) will remain protected under the Endangered Species Act.

USFWS’ decision was in response to a petition for delisting filed by the Pacific Legal Foundation, which argued the mouse was not a distinct subspecies and therefore did not warrant ESA protections. The USFWS concluded otherwise.

The mouse was listed as endangered in 1998 and has proven controversial as the subject of multiple litigation and petitions for delisting.

Emily Ronis is a Policy Communication Intern at The Wildlife Society. Read more of Emily's articles.