Tucson Region

Bat's 'endangered' listing a blunder, many experts say

ORGAN PIPE CACTUS NATIONAL MONUMENT - Few scientists think the federal government was right in 1988 when it listed the lesser long-nosed bat as endangered. In the 1980s, surveys sponsored by the U.S. Fish and Wildlife Service found only 500 bats in Arizona and 15,000 in Mexico. The agency feared the bat's "drastic decline" could harm the plants it feeds on, including saguaros, organ pipe cacti and the agaves used to make tequila. Grazing in Southern Arizona was restricted to protect foraging habitat. But when the summer sun sets here to unveil the Milky Way, up to 500 of the bats bolt from an old mine shaft each minute. By day, about 20,000 of the flying mammals are inside, hanging upside down. "The bottom line is, they missed large numbers of these bats," said Ted Fleming, a University of Miami bat expert who wrote the species' 1994 recovery plan. "Go to a place at one time and you won't see any bats. But go to that same place at the right time and you'll find tens of thousands of them." At a lava tube in Mexico's Pinacate Range, biologists in the past decade have consistently counted more than 100,000 lesser long-nosed bats, called "leptos" after their genus, Leptonycteris. The colony - off to the right as one drives from Tucson to Rocky Point - was unknown at the time of listing. Yet the same scientists critical of the bats' legal status still describe the creatures as vulnerable during their summer stay along the U.S.-Mexican border. That's because pregnant females cluster in a handful of maternity roosts, where the dark, cool microclimate provides a daytime respite for both bats and illegal border crossers. At Cabeza Prieta National Wildlife Refuge, southwest of Ajo, thousands of bats abandoned an old mine in 2002 and 2003. The refuge staff found black water jugs inside - a telltale sign of marijuana smugglers who mask light-colored possessions to elude the Border Patrol's night-vision goggles. A new fence around that mine appears to be working. The same tactic may be needed at Organ Pipe, where border crossers this summer came perilously close to the nation's largest maternity roost. "The eggs are very much in one or two baskets," Organ Pipe biologist Tim Tibbitts said last month as the sun bled into the western horizon, cuing the bats to flutter from the 1,000-foot-long tunnel. "We've probably been on a honeymoon with this roost and all the illegal activity out here. Unfortunately, that's about to end." Listing criticized

Today, species get listed as endangered in response to activists' petitions and ensuing lawsuits. But Fish and Wildlife pursued the bat's listing on its own and was heavily influenced by biologist Donna Howell. Howell, who couldn't be located for comment, had studied the bat since the 1970s. She'd written several peer-reviewed articles on leptos, including one in the prestigious journal Ecology, that were cited in the listing. A 1974 study she co-authored reported only 135 bats were found in all known U.S. sites. Other articles of hers argued the bats and certain agaves were declining in unison, leading Fish and Wildlife's 1988 listing to say "there is concern for the future of entire Southwest desert ecosystems." But three years later, two University of Arizona scientists published a scathing critique of the bat's endangered status and role as a pollinator. Lendell Cockrum, author of "Mammals of the Southwest," and Yar Petryszyn, associate curator of the UA mammals collection, combed through the studies Fish and Wildlife cited. They concluded the data were "a combination of overoptimistic estimates of past population sizes and overly pessimistic estimates of current numbers, both poorly documented." "Lepto is not an endangered species," Cockrum, 84, said recently. "If it's going to be strictly a truthful, biological thing, it should be delisted." The listing said harvesting of agaves in Mexico to make tequila, either legally or by bootleggers, "may have contributed substantially to the drastic decline in long-nosed bat populations." But Petryszyn says the bat's role as a pollinator was "tremendously overstated." "All you have to do is look at a map of the known range of the nectar-feeding bats and superimpose that on the known range of saguaros," he said. "Over half the saguaros have never seen a nectar-feeding bat in their life." Scientists now agree that bees, doves and other flying pollinators visit the desert plants once said to depend on leptos. But ecologists do believe the saguaro's white flowers evolved to attract bats by nearly glowing in the dark, while leptos evolved long noses and tongues to reach inside flowers. The bat also excretes cactus seeds across the landscape and is highly effective at spreading pollen, Petryszyn said. He believes they may fly hundreds of miles in a night, and he's counted bats visiting a single agave up to 5,000 times a night. Howell did rebut Cockrum and Petryszyn in an unpublished paper she sent to state and federal agencies. It argued recent surveys miscounted or misidentified bats, said University of Miami biologist Fleming. Disputes about bat populations are common because the animals are poorly understood and haven't been surveyed rigorously until recently, said Barbara French, a biologist at Bat Conservation International, an Austin, Texas, advocacy group. "It's not at all unusual for people to go to roosts at the wrong time," she said. "We don't oppose delisting species, as long as it's done in a way that continues to protect maternity sites" and foraging habitat. Grazing curtailed

No one is actively trying to delist the bat, or downlist it to threatened. Populations at Arizona's three maternity roosts are stable or rising, but the status of Mexican roosts is unclear, said Mike Coffeen, a Fish and Wildlife biologist. "I think we're pretty close in the U.S., but not in Mexico," he said. "I wish we could assist them with funding. The counts aren't getting done." Even if the bat lost the shield of the Endangered Species Act, officials would first enact protections for their roosts, he said. Although an endangered species can restrict land and water use on private and public property, leptos' regulatory bite has been modest since nearly all roosts are inaccessible and on protected federal lands. But ranching in the Coronado National Forest has been put under the microscope to gauge if cattle damage the agaves bats visit. That created a costly headache for Arivaca rancher Jim Chilton, whose wife, Sue, is a Game and Fish commissioner. In 1998, a Forest Service biologist concluded that grazing on Chilton's 27,940-acre Montana allotment could imperil Sonora chub and leptos, even though no bats or roosts had been found there. A 1999 biological opinion then excluded cows from 55 percent of Chilton's grazing lease. Chilton declined to comment for this story, but he testified about the situation before a Senate subcommittee last June, telling federal lawmakers protections for the two species cut his allotment's value by $150,000 and added $25,000 in costs. Ultimately, a federal judge threw out the biological opinion. Studying bats is tough

Scientists might be most affected by delisting leptos. Endangered species attract research funding, but they're so protected biologists sometimes can't get permits to do studies. "If this bat was delisted, would it be easier to study? Yes," said Organ Pipe's Tibbitts. "But would I be spending as much time on them? No." This summer, Tibbitts helped Karen Krebbs of the Arizona-Sonora Desert Museum track bats at Organ Pipe, seeking to find out if bats fly to Southeast Arizona to feed on agaves before heading south in fall. Last month, Krebbs confirmed that when she radio-tracked an Organ Pipe bat near Patagonia, 125 miles to the southeast. The study, though, was less than Krebbs hoped for. She wanted to inject radio transmitters - a routine process in wildlife biology. But the permit she got only let her attach them with glue that lasts a few weeks. Krebbs catches the bats by stringing "mist nets" that look like they belong on a volleyball court. Most bats avoid the net, but some get entangled. To the touch, their fur is as soft as a mink's, but they can bite - forcing handlers to get rabies shots. At Organ Pipe, bat numbers have risen in the past decade and were healthy this summer despite a spectacular failure of saguaro blooming across Southern Arizona. Flowering at Organ Pipe was just 10 percent of normal, perhaps due to the drought, but the bats appear to have switched to an early blossom of nearby agaves. Border crossers pose threat

The bats' impressive flying ability lets them be resourceful. But in a harsh land, desperate humans call upon the same adaptive skills, potentially putting the two species in conflict. In summer, when Arizona's western deserts endure some of the continent's hottest temperatures, caves and abandoned mines are coveted by both leptos and weary border crossers. "When the ambient temperature is 108 degrees, it's about 80 degrees in there, so it's a choice site," said Curt McCasland, biologist for the Cabeza Prieta National Wildlife Refuge. In 2001, there were already signs migrants were nearing an old mine where some 4,000 pregnant bats cluster every summer. The next May, nearly 6,000 bats were found, but in a few weeks there were only 10. The same thing happened in 2003. McCasland said he's sure drug smugglers were in the cave because of the trash and black water jugs inside, plus footprints were made by someone carrying a heavy pack. "If you come across the border with 40 pounds of dope on your back, this is the right spot to hole up for a day," he said. The crossers also built campfires nearby, he said, and smoke is one of the most common ways to drive bats from caves - especially in Mexico, where many fear all bats are of the vampire variety and bearing disease. To protect other bat caves, land managers install metal grates that let bats in and keep people out. But scientists say leptos can have problems navigating such barriers. So last year Cabeza Prieta spent nearly $10,000 on a 10-foot metal fence around the mine that also stops people from building campfires nearby. "It seems to have worked really well," McCasland said. Up to 5,000 bats were counted throughout this summer. Organ Pipe may try the same thing, but officials there worry the fence itself could attract too much attention.