Mexico-U.S. Partnership Makes Gains For Migratory Bats
by Steve Walker
Many of America's most ecologically and economically important bats migrate seasonally across the United States-Mexico border. Vital assets to both countries, these bats have been neglected far too long. The Mexican free-tailed bat (Tadarida brasiliensis) has declined dramatically in several areas where it was formerly abundant. Two other species, the greater and lesser long-nosed bats (Leptonycteris nivalis and L. curasoae), are already listed as endangered.
Although unfounded fear of bats has caused abuses on both sides of the border, the migrating bats face a constant threat in their overwintering caves in Mexico. Literally millions at a time have been burned, dynamited, or excluded from their roosts, mostly because of mistaken attempts to control vampire bats. In 1991, a BCI-sponsored survey conducted by Mexican bat biologist Arnulfo Moreno documented alarming losses at eight out of ten caves in Mexico known to have once sheltered the largest bat populations. Since that time, one of the two relatively stable caves has been destroyed by new highway construction, an event that sadly illustrates the urgency of protective action.
BCI's response is the Programa Para la Conservacíon de Murciélagos Migratorios de México y Estados Unidos de Norteamérica (PCMM), otherwise known as the Program for the Conservation of Migratory Bats of Mexico and the United States. PCMM has strong government and academic support in Mexico, where it is directed by Dr. Joaquín Arroyo and Dr. Rodrigo Medellín. Arroyo is president of the Asociación Mexicana de Mastozoologia, A.C. (AMMAC). Medellín is a faculty member at the Centro de Ecología, Universidad Nacional Autónoma de México (UNAM), and program coordinator for the Secretaría de Medio Ambiente, Instituto Nacional de Ecología. He is also author of the U.S. Threatened and Endangered Species Recovery Plan for the greater long-nosed bat.
The PCMM International Steering Committee has met twice in Mexico City in the past year to set program goals and coordinate work activities. The plan we have forged brings together many diverse yet interrelated projects. It combines both new and already established programs, which will focus on direct conservation action, education, and research. Descriptions of each of these programs follow.
Plans Underway to Protect Cave Roosts
Cueva la Boca, Tio Bartolo, and Cueva de los Coyotes in the State of Nuevo Léon near Monterrey are three critical winter cave roosts where dramatic losses have been documented for free-tailed and long-nosed bats (BATS, Winter 1993). All three of these caves have now been inventoried and targeted for protection.
Cueva la Boca at one time may have had the largest free-tailed bat population in North America, but is now occupied by a tiny fraction of its former numbers. In May 1995, I visited this cave with Merlin Tuttle and BCI Board Members Roy Vaughan and John Mitchell, completing a preliminary feasibility study for its protection. The cave is a short drive from Monterrey; it is heavily used by visitors who hike up the steep, rugged mountain trail to stand in the 100-foot-tall entrance and enjoy the view of the Sierra Madres. It also bears the scars of a crude phosphorous mining operation, now abandoned, as well as evidence of vandalism.
BCI has been in contact with government officials and the owner of the property surrounding the cave, and both parties have responded favorably to our proposed plans for protection. While we seek official protective designation for the cave from the Mexican government, we are also evaluating the feasibility of hiring a local steward and gating the entrance to protect the cave from vandalism. This interpretive steward would also be able to teach visitors about the bats' natural history.
The steward is only one part of our educational plan for the cave colonies. Under the leadership of Dr. Arroyo and Laura Navarro, a distinguished environmental educator, and with funding from BCI, Mexican educators are visiting the towns surrounding all three critical cave roosts to discuss residents' concerns about bats. Once the needs of each town have been assessed, educational programs will be designed and pilot-tested in each community. The results of the pilots will be evaluated and used to develop additional programs and materials for communities near critical roosting caves throughout central and northern Mexico.
Educational Programs Reach Many Audiences
Three other PCMM educational programs are also in full swing. The first of these is "Amos de la Noche," a Spanish-language version of the acclaimed "Masters of the Night" museum exhibit. The 6,000-square-foot exhibit opened in March of this year at the Centro Cultural ALFA, a museum in Monterrey, Mexico. Merlin Tuttle lectured to an enthusiastic crowd of educators, scientists, and children at the premier, and along with Dr. Medellín, Dr. Arroyo, and me, fielded questions at a national news conference held before the event. Monterrey is only the first stop for the exhibit, which is scheduled to tour most of the major cities in Mexico over the next four and a half years. "Amos de la Noche" will offer most Mexican citizens their first introduction to the natural history and ecological values of bats.
BCI's Spanish-language video, "Controlling Vampire Bats and Bovine Rabies," is the second component of our educational outreach. The video is now in its second year of distribution in Mexico and in Central and South America under the direction of BCI consultant Dr. Rexford Lord and with the financial support of the Fifield family. Dr. Lord has presented the video at major veterinary conferences, and more than 300 copies have been distributed to veterinarians, educators, and ranchers. These professionals are now taking the initiative to present the video and teach vampire control techniques in their own circles of influence. For example, Rodrigo Vargas Yanez, a faculty member at the Universidad de Morelos in Cuernavaca, has presented the video at four conferences this year and also at graduate- and undergraduate-level bat biology workshops.
The last component of BCI's educational effort is our participation in the "Forgotten Pollinators" campaign, for which I serve on the Advisory Board. The program is sponsored by the Arizona-Sonora Desert Museum under the leadership of Dr. Gary Nabhan. It is designed to promote awareness of the importance of bees, butterflies, bats, and other animals that pollinate wild plants and crops. Our plans include producing a number of different materials such as curriculum guides, brochures, a directory of speakers, and slide shows. These materials will illustrate the roles pollinators play in biodiversity and agricultural health, as well as the problems that threaten them.
A special outgrowth of the "Forgotten Pollinators" campaign is the inclusion of the lesser long-nosed bat in an educational project called "Journey North," sponsored by Hamline University's Center for Global Environmental Education. This award-winning international project allows students to participate in global studies of wildlife migration. Using reports that arrive over the Internet, participants chart different species' journeys across the hemisphere right to their own hometowns. Through first-hand experience, thousands of students in Mexico and the U.S. will learn about the importance of migratory bats.
Research Defines Conservation Direction
The effectiveness of our conservation efforts depends upon our ability to determine roost sites, population estimates, and behavioral information about key species. With the help of free-tailed bat expert Dr. Gary F. McCracken (University of Tennessee) and lesser long-nosed bat expert Dr. Ted Fleming (University of Miami), the PCMM Steering Committee has set four research priorities: to establish reliable population figures, to develop a comprehensive inventory of key roost sites in Mexico, to document ecological and economic impacts of feeding behavior, and to monitor population movements of bats between caves in Mexico and the U.S. Dr. Medellín is directing research activities for the lesser long-nosed bat from the Centro de Ecología, UNAM, while Dr. Arroyo is directing development of the comprehensive roost inventory database for all cave-dwelling species of Mexico.
We are fortunate to have enlisted the help of the U. S. Department of the Interior Bureau of Mines (USBM) for this project as well. In addition to funding assistance, the USBM will provide data through its NAFTA-related Borderlands Project to merge BCI's existing bat-habitat range information with USBM mine location data for all international border areas. The result will be a fully-operational GIS (geographic information system) database of all caves and mines, which will be invaluable for habitat analysis.
Our research on Mexican free-tailed bats is already underway with two projects in Central Texas directed by BCI and Dr. McCracken. The first of these projects began this past summer when we contracted with Bruce Sabol, a research scientist with the U.S. Army Corps of Engineers, to test a new technique using thermal infrared imaging for estimating populations of free-tails.
Our second project is being conducted by Ya-Fu Lee, a BCI scholarship recipient and doctoral student under the direction of Dr. McCracken. Lee has just completed the first summer of field work for his study, "The Feeding Ecology of the Migratory Mexican Free-tailed Bat." He will analyze feces of the bats at several of the largest nursery caves to identify and quantify the insects they eat, focusing on the bollworm moth, one of North America's most costly crop pests. Billions of these moths migrate northward into the United States each spring, and available evidence suggests that free-tailed bats are consuming large numbers of them. Lee will test this hypothesis using Doppler radar and ultrasonic microphones to simultaneously document bat and moth movements, backed by a simple antibody test of bat feces to confirm consumption of bollworm moths.
By uniting several of BCI's established programs with new partners and projects, the PCMM is developing a scope of influence that would otherwise be unobtainable due to high costs and cultural boundaries. These research projects and education and conservation campaigns will play key roles in ensuring a future for the millions of bats that cross our borders.
Steve Walker is BCI's Associate Executive Director and our program leader for the PCMM initiative.
Biologist Arnulfo Moreno collects data on the bats of Cueva la Boca. Moreno is an expert on northern Mexico's bats and a consultant for PCMM, the Programa Para la Conservacíon de Murciélagos Migratorios de México y Estados Unidos de Norteamérica.
The 6,000-square-foot "Masters of the Night" exhibit is the largest and most popular conservation exhibit about bats ever produced. "Amos de la Noche," the Spanish-language version, is giving many Mexican citizens their first real introduction to the ecology, values, and conservation needs of bats.
The greater long-nosed bat is one of the migratory nectar bats being studied in BCI's joint U.S.-Mexican research project. In the U.S., it is found in Texas and New Mexico and is officially listed as endangered. Scientists hope to answer questions about the dietary needs, foraging habits, and migration routes of these bats.
Ya-Fu Lee captures Mexican free-tailed bats as part of his BCI-funded study. Lee's research examines the feeding ecology of these bats to better understand their ecological and economic significance.