Canyon Sketches Vol 1 - July 2007 Bat Survey
Bat Survey Documents Grand Canyon Populations and Nursery Colonies
By Allyson Mathis
Available as an audiocast read by Shannan Marcak. Duration 3:26 (2.76MB)
Ranger Pam Cox has initiated the first survey of bat populations in Grand Canyon National Park since a baseline survey was completed in 1996 – 1997. Pam is one of the interpretive rangers stationed at Phantom Ranch, and is volunteering her time to the Division of Science and Resource Management in order to conduct the bat survey. At least 20 species of bats have been documented in Grand Canyon National Park, with 5 or 6 species common in the canyon. The western pipistrelle bat is the species most commonly observed as they are the small bat seen feeding on insects at dawn and dusk. Other common species of bats at Grand Canyon include the pallid bat and the Mexican free-tailed bat.
Mistnetting bats at Phantom Ranch
The purpose of both the 1996 – 1997 and the current survey is to gather baseline information on the status of bat species, and identify management needs for the protection of bats and their habitats. The surveys focused on establishing species occurrence, population numbers, and identifying cave roost sites. Pam’s current work focuses on re-establishing populations numbers in Stantons Cave in the eastern Grand Canyon, and in Bat Cave in the western Grand Canyon. In 1997, 57 Townsend’s big-eared bats were counted emerging from Stantons Cave. On July 15th, Pam documented 30 bats emerging from Stantons Cave, that based on visual monitoring, appeared to be Townsend’s big-eared bats. Later this month, Pam will conduct an emergence count of Mexican free-tailed bats at Bat Cave. In 1997, approximately 265,000 Mexican free-tailed bats were observed there.
Pam also visited Last Chance Mine, an abandoned copper adit, near the Grand View Trail on Horseshoe Mesa. A 1988 report indicated that a nursery colony of Townsend’s big-eared bats was found there. In late June, Pam observed 39 Townsend’s big-eared bats emerging from the Last Chance Mine indicating that it is still an active colony.
Identification of a western pipistrelle bat.
Pam will continue her work surveying bat populations in Grand Canyon National Park. In addition to her surveying trips to potential roost sites throughout the canyon, she does mist netting to capture and identify bats found in vicinity of Phantom Ranch. Pam states, “I'm really excited to be part of establishing these baseline numbers and hopefully we will be able to continue to monitor population trends here in the park well into the future. The bats here at Grand Canyon play a vital role in performing pesticide-free insect control in Northern AZ. It's important for the park to continue to manage roost sites in the park to ensure the protection of these bats.” Pam’s passion for bats is infectious, and the hikers and mule riders who are lucky enough to visit Phantom Ranch may have the opportunity to attend one of Pam’s ranger talks on Grand Canyon bats. The rest of us will benefit nonetheless from her important survey work on Grand Canyon’s bat populations.