Mexican long-nosed bats are moving farther north across the U.S.-Mexico border in their search for agave nectar, according to Bat Conservation International, which said Tuesday that new DNA evidence has confirmed the shift. The report points to swabbing agave plants and hummingbird feeders on the fringes of New Mexico’s Gila National Forest as part of a broader effort to understand where the endangered bats are traveling. The organization said the findings show the bats are traveling roughly 100 miles beyond their previously known roost areas in New Mexico.
The article said the bats have long been known to migrate each summer from Mexico into the southernmost reaches of the United States, with Big Bend National Park in Texas and Hidalgo County in New Mexico listed as destinations. It also said that DNA evidence helped add Arizona to the bats’ range only last year, reflecting how genetic sampling has continued to refine where the species is found.
In New Mexico, the Bootheel region has been hit hard by drought, and agaves there do not seem to flower as much as they used to, Kristen Lear said. Lear, who directs Bat Conservation International’s Agave Restoration Initiative, said the bats appear to be “trying to look for healthy agave food sources elsewhere,” adding that drought-stressed agaves in the Bootheel are part of what is “driving them farther north,” where flowering is less affected.
Bat Conservation International also said that additional movement along the route can lengthen the bats’ journey: the research described traveling another 30 miles as potentially adding another night to their trip. To keep nectar available along the route, researchers on both sides of the border said restoration of desert grasslands on the fringes of where bats have been found in the past will be key for ensuring the bats’ future and preserving the genetic diversity of the agaves.
The report said the species faces constraints that slow recovery. It said the Mexican long-nosed bat was added to the endangered species list in 1988 and that fewer than 10,000 are estimated to remain. It also said both the bats and agaves reproduce slowly, with the bats producing only one pup per year and agaves relying on the bats for pollination while taking a decade or more to flower and produce seeds.
Bat Conservation International said researchers and volunteers have worked to address those limits by planting agaves in what they call the nectar corridor. The organization said seeds are collected so more plants can propagate, that agaves can require a couple of years of rearing in nurseries before transplantation into high-priority areas, and that researchers have planted about 185,000 agaves since 2018. Rachel Burke, the group’s agave restoration coordinator for the U.S., said the New Mexico discovery underscores the importance of ongoing work to learn more about the bats, and that detecting the animals helps target planting and restoration efforts, while adding that more than 100 partners have joined the effort to continue sampling for DNA and surveying agave patches.