Bats control insects, pollinate plants and spread seeds, yet they are often undervalued, feared and understudied — and they face habitat loss, wind energy development, climate change, deliberate killing and disease, above all white-nose syndrome, a fungal disease that has killed millions of bats in the United States and Canada and is a growing threat in the West. Data on bat populations on National Park Service land are scarce, and at Glen Canyon National Recreation Area they were badly lacking.
So from 2016 to 2018 the park did the monitoring with the help of young people on river trips, in partnership with Grand Canyon Youth, a nonprofit in Flagstaff, Arizona, and river outfitters.
| Participants | 276 students, mostly in grades 6–12, and 80 young adults under 35 — 20 teachers and 60 river guides |
| Trips | 18 river trips to 17 sites on the San Juan and Colorado rivers |
| Recordings | 46,909 call files, of which 28,209 could be identified to species |
| Species | 14, including the park's first record of the greater mastiff bat |
The project had three aims: map where bats live and what habitat they use in the park; add good data to bat conservation across the continent; and turn participants into lifelong ambassadors for the National Park Service. New, easy-to-use acoustic equipment and better training have made citizen bat monitoring practical where it used to be rare.
Where
Glen Canyon covers 505,868 ha of the Colorado Plateau in Utah and Arizona, from 930 to 2,319 m in elevation, and its cracks, crevices and talus slopes offer bats plenty of roosts. The survey followed the partners' existing trip routes in three regions:
| Region | Stretch |
|---|---|
| Cataract Canyon | Colorado River mile 202 to the Hite, Utah, take-out — 32 miles |
| San Juan River | river mile 45 to the Clay Hills, Utah, take-out — 38 river miles |
| Lower Colorado River | Horseshoe Bend to the Lee's Ferry take-out, Arizona — 9 miles |
Acoustic bat monitoring sites sampled in 2016–2018, Glen Canyon National Recreation Area, Utah and Arizona.
How the students did it
Grand Canyon Youth, which leads educational river trips and already had a cooperative agreement with the park, recruited school and youth groups willing to run the curriculum on their trips. A mix of cooperative agreements, grants and verbal agreements kept the partnership going for three years. (The Federal Grant and Cooperative Agreement Act of 1977 lets agencies fund partners toward shared goals where there is a public purpose and substantial involvement.)
A staff member from the park's Division of Science and Resource Management went on each trip to explain the research and teach the protocol, along with bat physiology, ecology, threats and research methods. To let participants experience the bats around them:
A student using an EchoMeter Touch, which identifies bat species from their calls in real time. San Juan River. NPS photo
- an EchoMeter Touch displayed and identified echolocation calls live;
- a Baton detector turned calls of 20–80 kHz into sounds people can hear (0.2–20 kHz);
- laminated slides showed bat anatomy and maps of white-nose syndrome's spread.
Students using an EchoMeter Touch (right) and a Baton (left), which brings bat calls down to a range the human ear can hear. San Juan River. NPS photo
The survey. Between May 4 and October 24 each year, students set up SM4BAT-FS acoustic detectors at campsites, following the NPS guidance for acoustic bat surveys: away from canyon walls and other smooth surfaces that cause echoes, and facing flight corridors. They noted the main vegetation and the weather when they set the detector up and when they collected it. Detectors recorded from 15 minutes before sunset to 15 minutes after sunrise, capturing full-spectrum calls as uncompressed WAV files. Groups camped one night at each site, so each site got one night per trip; not every site was sampled every year, but each region was sampled at least once a year.
Students deploying an SM4 bat detector. San Juan River. NPS photo
The team classified calls with SonoBat software, checked by hand the spectrograms of any species never physically captured in the park, and shared the data with the NPS Bats Acoustic Survey Database and the North American Bat Monitoring Program (NABat).
Who took part
Youth and young adult citizen scientists taking part each year, 2016–2018.
Schools: Kanab High School, Northland Preparatory Academy, Orangewood Middle School, Page High School, Page Middle School, Sinagua Middle School and Spring Street International School.
Youth programs: Grand Canyon Youth Canyon Discovery, Grand Canyon Youth Middle School Adventure, Haven, No Barriers Youth – Children of the Fallen, No Barriers Youth – Learning Afar, and the Southwest Conservation Corps Ancestral Lands Program.
Because many of the teachers and guides were 35 or younger, they were counted as youth participants too — 356 in all (the 80 young adults exclude one trip for which the team could not get their details).
What they found
Species recorded (14): greater mastiff bat, Brazilian free-tailed bat, pallid bat, big brown bat, spotted bat, Allen's big-eared bat, silver-haired bat, hoary bat, California myotis, western small-footed myotis, fringed myotis, long-legged myotis, Yuma myotis and canyon bat.
The surprise. The greater mastiff bat (Eumops perotis) had never been recorded in the park, and its range maps do not reach Glen Canyon. It turned up at 10 sites, in every region.
Expected but not confirmed. Range maps and surveys of neighboring public lands suggested 18 species; the students documented 13 of them, plus the mastiff bat. Not confirmed: big free-tailed bat, Townsend's big-eared bat, western red bat, western long-eared myotis and little brown bat. SonoBat labelled some calls western red bat, little brown bat or "Nyctinomops species," but none survived manual checking — and the software cannot reliably tell the big free-tailed bat from its relatives.
Everywhere bats. California myotis and canyon bats were recorded at all 17 sites in every year, except Lunch Beach in 2018.
The San Juan was richest, with all 14 species — the only region with western small-footed and long-legged myotis. Oljeto (8 nights) and Slickhorn Canyon (7) were the most-sampled sites, and so have the most recordings; Upper Twin Canyon had the highest mean number of calls per night.
Bat species richness at each site, 2016–2018. Cataract Canyon in yellow, San Juan River in blue, lower Colorado River in red.
| Region | Sites | Times surveyed |
|---|---|---|
| Cataract Canyon | 7 | 10 |
| San Juan River | 7 | 24 |
| Lower Colorado River | 3 | 4 |
The authors caution that the San Juan's lead is partly an artifact of effort: it got far more survey nights, and its surveys ran May 15–July 1, in the summer breeding season when bats are most active, while the other two regions were surveyed mostly in early May or in September and October. More, and more evenly spread, summer surveys elsewhere would show whether the difference is real — or down to habitat or seasonal use.
Beyond the bats
On some trips the students also collected samples for an aquatic food-base study, the national Dragonfly Mercury Project, and the inventory and control of invasive plants. Many said the trip changed how they saw the outdoors; one participant from 2017 and 2018 described it as a push out of their comfort zone, a way past their fears and a new way of seeing the San Juan's landscape. Several participants went on to volunteer at Glen Canyon, and one later got a job with the Utah Division of Wildlife Resources. Surveys after each trip, and a longer-term follow-up, could show how well the curriculum works and whether it draws people into science or the parks later.
What it shows
- The data give Glen Canyon a baseline of bat distribution in three regions — the start of a long-term monitoring program that could track what climate warming or the arrival of white-nose syndrome does to the bat community.
- Partners who already know how to get non-scientists into remote country made the monitoring cost-effective.
- Cooperative agreements with education-focused outdoor organizations may be a fast way to grow citizen science across the National Park Service, and partnerships with neighboring parks and public lands could scale it up.
Sources
Based on Carpenter GM, Pilkington LH, Wharton EC, Tallman SJ, Berg ML, "Citizen-based Acoustic Bat Monitoring Along the Colorado and San Juan Rivers," Intermountain Park Science 1(1), 2021, National Park Service — by NPS biologists and the executive director of Grand Canyon Youth, published by the National Park Service. The abstract counts six schools and seven youth programs; the results name seven schools and six programs, and those named lists are used here. A participant's quoted reflection is paraphrased without their name; rewritten in hubnx's own words.
In these publicationsGlen Canyon National Recreation Area
Licence: CC0 1.0 (public domain) · Adapted from www.nps.gov
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