Learn about our recent expedition to Sierra de las Cacachilas

“You just saw the smallest owl on Earth,” whispered Gerardo Marrón, head ornithologist at Pronatura Noroeste, as the 5-inch-tall bird flew away from the gawking scientists and into the night.

Moments earlier, the team was busy projecting an assortment of owl calls into the night, trying to lure and document the beautiful birds that become active after sundown. Later, when the elf owl’s yellow eyes stared back at curious ones under a star-speckled sky, an overwhelming sense of awe fell over the group.

Awe is a word that best captures the feelings that predominated the recent scientific expedition to Sierra de las Cacachilas—the first in a decade. After a generous season of rainfall, the mountainous region’s booming green landscapes and blooms made for an extremely productive excursion. Rare snakes, barely known arachnids, plants never before seen in that area, and new bird visitors were all important expedition findings. 

Scientific expeditions can be thought of as the first step in conservation—they are a way to gather baseline data on the plants and wildlife that exist in a specific area, which can then inform actions to protect it. These research trips have been happening for hundreds of years (think Charles Darwin’s trip to the Galapagos) and help us better comprehend our natural world. 

This destination, Sierra de las Cacachilas, is an extremely biodiverse and perhaps equally understudied area at the tip of the Baja California Peninsula. The visit by Museum researchers, alongside several collaborating Mexican research institutes and organizations, means that nature at this site is being slowly unveiled and understood.

The trip was also multi-disciplinary, which means there were several different teams dedicated to a specific topic: herpetologists studied the Sierra’s reptiles and amphibians, ornithologists focused on birds, botanists documented plants, and our invertebrate zoology team made sure no insect or arachnid went unnoticed.

Some of the main expedition findings thus far:

• The botany team (armed with lots of curiosity and a Ziploc bag full of spaghetti) ventured to the highest and most remote location of the study site, where they found many plant species that do not occur in other parts of the Sierra Cacachilas, but only occur on a few other higher elevation mountain tops in the Cape region such as the Sierra la Laguna. These plants included a yellow-eyed-grass called Sisyrinchium tranlucens.
• The invertebrate zoology team was on a hunt for an undescribed species of Opiliones (a type of arachnid commonly referred to as daddy long legs). The team was dedicated (and lucky) enough to collect two specimens of the undescribed species, which has only been found in two other locations before this.
• In addition to encounters with the tiny elf owl and other amazing birds of the region, the ornithology team also registered the first ever sighting of a least Bell's vireo at this site. These birds are endangered and winter at the tip of the Baja California Peninsula but nest in Southern California—true explorers of our mission region.
• Thanks to the herpetology teams’ daytime and nighttime surveys, they found the Baja California ratsnake (Bogertophis rosaliae), which is uncommon to see. In fact, we know so little about the snake that scientists have only seen it eating something in the wild twice... until now. The herpetology team observed a ratsnake perched at the entrance of a cave ready to catch its dinner: bats flying out into the night.

These are just a few of the incredible findings from what will be the first of many expeditions to Sierra de las Cacachilas over the next two years. To learn more about other expeditions we’ve led in the past and why they matter, click here.

We recognize the many participating Mexican organizations and research institutes that contributed to this expedition, including CIBNOR, UABCS, UABC, Fauna del Noroeste, Pronatura Noroeste, and Rancho Cacachilas. We are grateful to Innovaciones Alumbra for their support in making this and future expeditions come to life.

Entomologist Rachel Allingham prepares to net a specimen.

Although physically strenuous, the expedition's hiking route offered an incredible array of landscapes to enjoy.

This image taken by Curator of Invertebrate Zoology Shahan Derkarabetian, shows an undescribed Opilione—this species is entirely new to science.

Curator of Botany Jon Rebman uses a simple and reliable tool to document the site's flora: his phone.

The ornithology team was busy documenting birds. If you look closely, you can see a small band on the cactus wren's left leg, which helps scientists estimate population size through mark and recapture.

Much of the expedition's "downtime" was actually spent processing specimens from the field. Here, Collections Manager Adam Clause prepares a snake so it can be preserved and studied for many years to come.

The botany team found a unique yellow-eyed grass that only grows at high elevations, Sisyrinchium tranlucens.

Entomologist Eva Horna-Lowell uses an aspirator (affectionately referred to as a "pooter") to collect specimens against a black light and white sheet.

Mammologists Jonathan Villareal and Carolina Mora Sandoval prepare a net to survey for bats as dusk begins to approach.

Scientists participated in an outreach event to share findings from their expedition. In this picture, botanists Carlos Lim and Jon Rebman show different flowers to visitors.

Many nights were spent discussing findings, or just having a laugh.

Botanist Abraham Sánchez performs a complete floristic survey of a unique micro-habitat.

Our scientists show an incredible pair of stick bugs. Although they are the same species, the male (left) is significantly smaller than the female (right).

Not all wildlife can be seen during the day. To document nocturnal animals, Mammologist Jonathan Villareal sets up camera traps overnight.

The invertebrate zoology team hikes against a beautiful view and a scorching sun.

Posted by Paula Sternberg Rodríguez, Senior Manager of Communications on November 24, 2025