Border Wildlife Study

Documenting Wildlife in the Path of the Border Wall

Sky Island Alliance Stewardship Specialist Bryon Lichtenhan checking a wildlife camera for the Border Wildlife Study.

Sky Island Alliance’s binational Border Wildlife Study documents the remarkable diversity of wildlife species under imminent threat from active border wall construction between Arizona and Mexico. Established in partnership with Naturalia, our camera array has collected over 12,000 wildlife photographs and documented over 106 species in the path of the border wall since its launch in March 2020.

Border wall construction has bisected one of the most rugged and wild stretches of wildlife habitat on the U.S.-Mexico border—threatening to stop animals in their tracks in the most biodiverse region in inland North America. Because dozens of federal laws (including the Endangered Species Act and National Environmental Protection Act) have been waived since 2019, border wall construction of 30-foot-tall steel walls have risen in sensitive areas that support local wildlife and springs.

In July 2020, wall construction began across the southern end of the Huachuca Mountains, located 70 miles southeast of Tucson, AZ and at the southern terminus of the Arizona Trail. Later that year and into early 2021, wall construction and new border roads rapidly approached our study site—critical territory for jaguars, mountain lion, ocelots (whose reintroduction to the US is a focus of binational conservation efforts), pronghorn, black bear, elf owls, box turtles, and dozens of species of butterfly.

Our Border Wildlife Study contributes vital data to document and monitor wildlife at the border.

From October 2020 through January 2021, we witnessed construction, water pumping, and increased road traffic on the eastern and western sides of the Huachuca Mountains. Sky Island Alliance continues to document which species live in the heart of the Sky Island region — and advocate for the removal of border wall in critical areas — before the wall completely severs the landscape.

This study is supported by the Patagonia Foundation, Papoose Foundation, New York Community Trust, Wilburforce Foundation, and generous individual gifts that keep our cameras running 24/7.

El muro fronterizo entre Sonora y Arizona es contrario al espíritu de cooperación entre su gente, a la cultura compartida y a un territorio con alta biodiversidad que se mantiene por los corredores biológicos compartidos.

— Gerardo Carreón, Director de Conservación de Naturalia A.C.

Study Results So Far:

Several million photos have been analyzed since the launch of the study in March 2020. From this data, we have collected more than 12,000 wildlife photos and documented over 106 species of mammals, birds, reptiles, and insects. We’ve found that the diversity of species in our study area is incredibly high (over 60 square miles, which is roughly the size of Washington D.C.) and includes 30 mammal, 48 bird, and 28 insect and reptile species — and counting!

Species highlights from the Border Wildlife Study include:

Mountain lion and black bear have been detected in both the Huachuca and Patagonia Mountains. Wide-ranging species like these large mammals need expansive territories to find enough food, water, shelter, and mates to thrive and are likely to be cut off from the Sky Island mountain ranges they roam between when the wall is built and their corridors are blocked.
Elf owls were photographed on our cameras in spring 2021 during their annual migration between Mexico and Arizona. Native to Northern Mexico and the Southwestern U.S., these birds are the smallest owls in the world and fly northwards to breed and hunt insects during the summer. Research has shown that their cousins, the ferruginous pygmy-owl, do not fly over short border walls. Elf owls may very well lose their migratory access to the U.S. once the new tall wall is built.
Coati, hooded skunks, and hog-nosed skunks have been documented along the border. These three sub-tropical species are abundant in Mexico and only live in the U.S. borderlands. Once the wall is built, the small U.S. population will be isolated from core populations to the south.
Porcupine and a Mexican subspecies of Virginia opossum, two unique mammals, have also been detected in the borderlands. Our study area is the northern distribution limit for the opossum and the very southern distribution limit for the porcupine. Detections of these species are uncommon and exciting.

Continuous connected oak woodland with a large amount of canopy cover is vital habitat for a great number of the mammal species we’ve detected in this region. Wildlife relies on these woodlands for shade, food sources, and shelter from predators.
- In fact, we found that mammal diversity is greatest in the higher elevations of the Patagonia Mountains—where canopy cover abounds thanks to the range’s plentiful oak woodlands.
The most bird species are in the San Rafael Valley. We’ve found an extraordinary number of bird species living in or migrating through these expansive border grasslands.
Mammals are more active at night. We were intrigued to find that 71% of all mammal sightings occurred between sunset and sunrise. Over half of the mammal species we’ve detected have only been seen at night—indicating that light pollution from border infrastructure could impact a majority of mammal species in the area if wall lighting is installed

See All Detected Species

The wildlife cameras used in this study are designed to photograph mammals, but birds, reptiles, and even insects have also been documented.

Science Behind the Study

The Border Wildlife Study collects wildlife community data with a camera array spanning over 30 miles of the border across the Patagonia and Huachuca Mountain foothills.

The Border Wildlife Study transverses the Patagonia and Huachuca Mountains in Southern Arizona, an area of border only marked with barbed wire and vehicle barrier today but where border wall construction is planned.

We designed this study to scientifically document which vertebrate wildlife species are migrating through and residing permanently in this section of border that remains passable for animals. The camera array is deployed across a grid with 58 camera observation points spaced 2 km apart in the U.S. and Mexico. A total of 62 cameras are deployed across this array (some camera observation points have duplicate cameras) to document animals moving within 100 feet of each camera lens. The passive infrared cameras trigger when they sense motion and heat to capture images of wildlife 24 hours a day and 7 days a week.

Cameras are deployed across a systematic 1 km x 1 km grid, where each camera is within 3 km of the U.S.-Mexico border. The red line is the international border and yellow markers are camera locations in Mexica (left) the U.S. (right).

This design creates a network of camera points optimized to detect both wide-ranging large mammals like jaguar and small animals like coati and birds. Our design is based on the global wildlife monitoring standard—TEAM Terrestrial Vertebrate Protocol (2011)—also used by the National Park Service, Parks Canada, and numerous wildlife biologists in ecosystems across the planet. Because the TEAM protocol selects regularly spaced camera locations across different landscape features and habitats, it removes bias in camera placement and increases the likelihood of documenting the true breadth of the wildlife community. It allows for direct scientific comparison between camera points because they are selected the same way.

Once we establish which species comprise the wildlife community present today, we will monitor for change in the community over time, if and when, the border wall cuts through this landscape. Our data will evaluate aspects of the wall’s environmental impact and guide the future protection and restoration of vital wildlife pathways.

Reference: TEAM Network. 2011. Terrestrial Vertebrate Protocol Implementation Manual, v. 3.1. Tropical Ecology, Assessment and Monitoring Network, Center for Applied Biodiversity Science, Conservation International, Arlington, VA, USA.

How to Take Action

Take a stand for borderland wildlife and help advance our Border Wildlife Study by:

Sponsor a Wildlife Camera—Donate to help keep our cameras running 24/7.
Volunteer for the Study—Help identify species photographed by our Border Wildlife Study cameras. With each camera collecting around 6,000 photos each month, our wildlife biologists have a lot to look through! By participating in our new Zooniverse community science projects, you can see photos from the field, test your species identification skills, and contribute invaluable data to the project!
Raise Awareness about Wildlife at Risk—Spread the word about wall construction and its threats to wildlife at the border with your friends and family.