southern california


Observing Behavior in the Wild


One of our camera traps caught this deer mouse heading for a burrow.

My favorite part of the fieldwork I do (see: A Night with the Pocket Mouse Field Crew)  is watching the pocket mice, kangaroo rats, and other small mammals in the wild. I love releasing them from a trap and watching them take a sand bath, or dig up a cache of seeds they buried previously, or sometimes dive into the closest burrow and get chased right back out by its owner who was already inside.

While the reward (and often the data!) of an animal behavior study is observing your subject do what it does, figuring out how to make the observation can be one of the biggest challenges. You don’t want your presence to affect what the animal is doing—unless you are observing their response to humans.

With big animals that live in fairly open environments, sometimes you just need to be far enough away. As an undergraduate I worked as a field assistant on a pronghorn project in Montana. We hiked up hillsides and watched for females to get their babies out of hiding to nurse. We used binoculars and spotting scopes so we could see well enough to note ear tag colors, yet distant enough to not make the animals feel threatened by our presence.

With the pocket mice, that are so small, quick and nocturnal, getting far away and sitting quietly doesn’t work very well. I spent a dozen or so nights trying, outfitted with a camp chair and night-vision goggles. I set out some seeds on a tray and hoped the pocket mice would come. With one exception, they did not. Those were some of the longest nights I have ever experienced, sitting in the dark, staring at nothing.


Andrea Sork, a field assistant, uses night vision goggles to observe a kangaroo rat. On the right is an infrared camcorder.

What ended up working was trapping them first and then putting the tiny rodents inside a clear arena with the seeds, so I could watch them through the sides. While it isn’t perfect—they spend time exploring the walls and digging to get out—it at least allowed me to see them! And most of the animals decided that the seeds inside the arena were worth taking; even though I was sitting 12 feet away, the mice made multiple trips to the seed pile and back to their burrow. It helped that I sat very still and quiet the whole time. But it was exciting watching the animals come and go!

In addition to physically watching the pocket mice, camera traps can be hugely important. You can set multiple cameras at once and leave them for many nights. Later, as you go through the photos and videos, you can see where the mice were and what they were doing—especially if you leave food trays or set them at burrow entrances or some other specific place. The upside is that you can have a lot more “eyes” out at once, and cameras are less intrusive than a person sitting there. The downside, though, is that you can’t be sure cameras are catching everything, and they often have a pretty narrow view.

If you get a chance to see some animals in the wild, take an extra moment to watch them do their thing. Normal activities like sleeping or eating are a feat to witness, and there is so much to learn just by sitting still and watching!

Rachel Chock is a graduate student and volunteer with San Diego Zoo Institute for Conservation Research’s Pacific pocket mouse project. Read her previous post, Protected Habitat in Southern California.


The Desert: Blooms and Hail

Grape-soda lupine

San Diego County is the most botanically diverse area in the U.S., with nearly 2,000 species, many of which are endemic (unique to a defined geographic area, so many are found only in San Diego County). There are not many places where you can experience the ocean, the snow, and the desert within a couple hours. The desert transition habitat is found down the east side of the Peninsular Ranges, and this is the site of our recent seed collection trip. The weather forecast looked ominous, but we were optimistic. To get to our site, we had to drive up and over the Cuyamaca Mountains and out into the lower elevations beyond.

Apricot mallow

When we finally reached our site, we saw a mix of cacti, shrubs, and huge granite boulders. It was freezing cold and very windy. At certain points the wind became so strong it was difficult to open the truck doors to get out and identify plants. Despite the rough conditions, it was a beautiful place to explore. We saw desert apricot Prunus fremontii, golden gooseberry Ribes quercetorum, and grape-soda lupine Lupinus excubitus in bloom.

As the day wore on, the weather only got worse. When we tried to collect a sample of apricot mallow Sphaeralcea ambigua, the rain turned to hail, and we decided to admit defeat for the day.

McCain Valley overlook

On the drive back up and over the Cuyamacas, the hail turned to snow! It was so much fun to watch everything turn white throughout the course of our drive. We followed a snowplow most of the way down the mountain; I never would have imagined experiencing something like that in Southern California! As we dropped in elevation, the snow slowly changed back into rain and everything turned green again. It was odd to realize that we had only been a half an hour away from the ocean.

San Diego is truly a remarkable place, and I couldn’t ask for a better area to study plant diversity.

Lauren Anderson is an intern at the San Diego Zoo Institute for Conservation Research through the Bureau of Land Management’s Seeds of Success Program. Read her previous post, Wake Up, Seeds! Germination Testing.


Mountain Yellow-Legged Frogs: Life Beyond the City

The San Gabriel Mountains tower over the Los Angeles basin like sentinels. Heading up a winding highway into the mountain wilderness leaves all signs of the urban landscape behind. Stoplights, mini malls, and highways are replaced with trees, birds, and steep cliffs. Climbing further up the mountain reveals a wilderness teeming with amazing sights and a cacophony of sounds that stimulate the senses. Colorful butterflies, amazing wildflowers, and chirping frogs are all regular parts of the mountain landscape.

As a biologist with the San Diego Zoo Institute for Conservation Research, Southern California’s mountains are my office and outdoor laboratory. The goal of my research is to improve our understanding of the critically endangered mountain yellow-legged frog Rana muscosa with the ultimate goal of reintroducing poopulations back into the mountains of Southern California. Every summer for the last three years I have headed up into the mountains to learn as much as possible about these magnificent and beautiful frogs. One third of the world’s amphibians are in decline, and by focusing our research on the mountain yellow-legged frog, the San Diego Zoo is working to do our part to save frogs from extinction.

Scientists noticed that mountain yellow-legged frogs were experiencing severe declines in Southern California during the 1990s, and in 2001 they were listed as an endangered species under the Federal Endangered Species Act. The exact reason for the drastic declines are unclear, but we suspect that the deadly amphibian chytrid fungus may have played a major role in population declines. In addition, the species faces pressures from habitat loss, wildfires, water pollution, global warming, and introduced predators. Today only nine populations of mountain yellow-legged frogs exist in Southern California.

This summer I am focused on understanding the population demographics of wild mountain yellow-legged frog tadpoles. With the assistance of our summer research fellow Stephanie Wakeling, we are hoping to gain insight into the survival rates of tadpoles during their two to three years of life before they metamorphose into frogs. Keep an eye out for a regular series of blog entries as we share this exciting research with you throughout the summer.

Frank Santana is a research technician at the San Diego Zoo Institute for Conservation Research. Read his previous post, Desert Memories.