Projects in the Field

Projects in the Field


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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.


CSI: Coronado












Terns, Plovers, and People: Living in Harmony












Learning What We Can Learn from Camera Trap Photos: Part 1


Andean bears are sometimes called spectacled bears because of the rings of lighter colored fur around their eyes.

Others have said it before and it’s true: New forms of technology such as camera traps make it possible for field researchers to collect information we could previously only dream about. Technology advances so quickly that we’re still evaluating what we can do with these tools and what questions we can and cannot answer by using them. We have many basic questions that are still unanswered even for species as large as the Andean bear. Here are two of the most basic: How many are there? Are the populations increasing, stable, or decreasing? The answers to these questions and others would help researchers, conservationists, and governments decide how much of their limited resources to invest in research efforts and conservation actions, in the hopes that 100 years from now there will still be bears roaming the forests of South America. Unfortunately, there are still no answers to these questions.

How would you answer these questions? How do you count animals that live in dense forests in rugged habitat, when those animals avoid contact with humans? It’s been said for decades that the markings of individual Andean bears vary so much that you can identify each individual bear just by looking at it. If that’s true, then maybe we could use camera traps to identify individual Andean bears in photographs and then estimate population sizes and densities. However, how do you test whether individual bears can be reliably identified in photographs? In order to test this you’d need photos of a lot of different bears whose identity you definitely knew. That means you can’t just use photos of wild bears from camera traps, because you don’t know how many bears walked in front of the camera traps.


Compare the markings of this bear, Tommy, with the bear above (named Turbo) and notice the differences.

The only way we could think of to test this was to take photos of different bears from captivity, so we’d know the identify of the bears, ask people to compare those photos, and keep score of whether bears were correctly identified, or not. When a group of international collaborators and I did this we were surprised to discover that people were initially not very good at this task. In fact, they would have done just as well if they’d flipped a coin! That’s really not the kind of result we were expecting, or hoping, and it led us to consider whether we were over-confident in our own abilities to identify individual bears. However, it turns out that with a little practice and training, participants became better at identifying bears from their photographs. After thorough review and discussion by other scientists, this work has been published in the journal Wildlife Biology and you can read all the details and see more photos here.

So, the good news is that, if we’re careful, we and other field researchers can use photos from camera traps to identify individual Andean bears, estimate the sizes of their populations, and compare populations densities. Now, we “just” need to get the cameras into the forests where there are bears!

Russ Van Horn is a scientist at the San Diego Zoo Institute for Conservation Research. Read his previous blog, Ambassador Mi Ton Teiow Receives a New Posting.


Plover Hide and Seek








chick revealv1







Breeding Strategies: Secretive Plovers & Gregarious Terns











The Art of the Western Snowy Plover’s Nest


Some snowy plover nests are a simple scrape in the sand, adorned with shells. (Photo: Anjanette Butler, SDZG on MCB Camp Pendleton)

Unlike most beach-nesting shorebirds, the western snowy plover has taken nesting to the level of an art form. I have been monitoring this threatened species during the nesting season as part of my job as a research associate with the San Diego Zoo Institute for Conservation Research. Previously, I primarily searched for snowy plover nests along the Oregon Dunes, as well as California beaches with dune habitat. Our current study site at Marine Corps Base (MCB) Camp Pendleton offers a more diverse habitat.

Because of their nesting strategy, I become more intrigued with snowy plovers the more I get to work with these resilient birds. Before the eggs are laid, the male creates some nests by making various circular scrapes in the sand and the female selects the one she likes best. I have seen some of these simple nests adorned with decorative shells, others that incorporate the available vegetation along the dunes, and even quite a few containing woody debris that can be found concentrated along the creeks.

I’ve been impressed by how well the plovers use the resources—both natural and manmade—available to them. Last year, lobster traps sometimes washed up on beaches we were studying in Ventura, California and a plover used one of them as a nest site. The lobster traps looked very much like the mini-exclosures we use to protect nesting birds from predators. Made of wire mesh and shaped like a square (with small openings so the adult plovers can exit when needed); we place an exclosure over a plover nest until the chicks hatch. Apparently, the plovers there had gotten used to the protection offered by the exclosures, and the nesting pair that used the lobster trap did indeed successfully hatch and raise their chicks.


Western snowy plovers are adaptable, using available resources when nesting. (Photo: Anjanette Butler, SDZG on MCB Camp Pendleton)

In contrast, our study site at MCB Camp Pendleton is more remote, so the birds there must rely on the available natural resources when selecting a nesting site. This year, we have some birds nesting along a creek. I could not believe how well one of the nests blended in with the woody debris and rocks around it—I almost did not see it at first! I feel so good when the birds’ hard work pays off and we get to see their chicks hatch. Hopefully, they will survive and continue in their parents’ footsteps.

Western snowy plovers face many challenges each day. Predators like crows and ravens, intelligent birds that are great problem solvers, are a constant threat to the plovers. It is possible that the plovers are sometimes testing out ways to keep these and other predators from locating their nests. This might seem like an obvious observation, but shrinking habitat availability in critical plover habitat can create the need for the plovers to find new ways to adapt to disturbances. It is vitally important for us as individuals to respect these birds during this busy nesting season on the beach.

I look forward to more discoveries while monitoring the western snowy plovers and their chicks on the beach.

Anjanette Butler is a research associate with the San Diego Zoo Institute for Conservation Research.


Name Our Jaguar Cub for Conservation

The male jaguar cub at the San Diego Zoo is getting a lot of attention for his off-the-charts cute ratings, but this little boy needs a name. Animal care staff have worked together to come up with a list of possibilities and now we want to hear what you think. Vote here.

The jaguars at the Zoo are just three of the jaguars that San Diego Zoo Global is working with. Scientist Mathias Tobler, Ph.D, has spent more than 10 years working in the Peruvian Amazon. He is using radiotelemetry, GPS collars, and camera traps to study jaguars and other keystone species’ role in the Amazonian ecosystem. Tobler is using this technology to learn about how undisturbed populations of jaguars use their habitat, their movement patterns, home-range size, density, and their foraging ecology to create a baseline to evaluate future impacts on this species caused by human development. This data will help to inform conservation decisions and recommend ways to mitigate impacts to wildlife during the planning stages of development projects near the most pristine and bio-diverse terrestrial ecosystem on Earth.

Jaguar (Panthera onca)

At San Diego Zoo Global we’re working to understand jaguars, as well as pumas, peccary and tapirs, and have seen improvements in the techniques of capturing, tracking and observing animals. It has also been noticed by the Peruvian government and the research team has been asked to advise Peruvian officials on monitoring systems for animals in this area.

Studying jaguars in the Peruvian Amazon is just one example of how San Diego Zoo Global is working to #endextinction for endangered species. To find out more about this project and others please visit these resources:

Counting Jaguars in the Amazon

Looking for Jaguars in the Night

Matt Steele is senior social media planner for San Diego Zoo Global. Read his previous post, 11 Bellies You Really Need to Rub.


Little Green Guards Excitement!










Two Little Green Guards inspect the camera trap,

Two Little Green Guards inspect the camera trap,

