Projects in the Field

Projects in the Field


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


Feathers from a California least tern mark the scene of the crime. (Photo by Maggie Lee Post, courtesy Naval Base Coronado)

I never expected to gain detective skills on the California least tern and western snowy plover project. As field biologists, our observation skills are critical in assessing nest success, chick survival, and other aspects of population ecology throughout the season. There are times when we walk up to a nest and something is amiss: the eggs are missing, an egg is punctured, or sometimes we find only pieces of broken egg shell in the nest cup. This is when we get to an interesting aspect of our job: ‘crime scene’ investigation! Many predators try to take advantage of the hundreds of eggs in a tern colony and those in plover nests. We partner up with predator biologists to help solve these cases of nest predation and prevent more from happening.


Can you make out the American crow tracks left at this crime scene? (Photo by Billy Smith, courtesy Naval Base Coronado)

Early in the season this year, when the first nests were being filled in the tern colony, the common raven and American crow (members of the Corvidae family) were the main threats. Clues left at the scene of the crime included tracks, pieces of egg shell, and sometimes even remnants of yolk in and around the nest cup. Once these clever birds figured out that we used small green sticks to mark each well-camouflaged nest, they found several other nests at one site. We quickly changed our marking tactics, and began using sea shells to mark nests.

In the middle of the season, when the tern chicks were reaching that stage when they were just beginning to fly, we saw an increase in predation by raptors. Peregrine falcons and great horned owls were linked to some of the crimes. These skilled hunters make swift kills but leave messy crime scenes containing tracks, feather piles, and sometimes leftover pieces of their prey.

Birds are not the only hunters in the area. Skunks and other small, opportunistic mammals use their keen senses to find and eat tern and plover eggs. Since most of these terrestrial creatures forage around dusk or at night, we are able to detect tracks and other signs during our morning patrol—and we definitely smelled a skunk’s presence at one of the beaches! Skunks are especially problematic because they are capable of digging under the exclosures we place over the plover nests to get to the eggs.

Predator management is no easy task, and the predator biologists do an excellent and professional job. They come up with inventive scare tactics and other methods to alleviate the pressure on our protected birds. Our partnership gives the terns and plovers a chance to incubate their eggs and raise their chicks in peace. This is why I’m out here using my detective skills to help the terns and plovers nest successfully on the beaches of Coronado. Case closed.

Melissa Murillo is a research associate at the San Diego Zoo Institute for Conservation Research.


Terns, Plovers, and People: Living in Harmony


This beach on Naval Base Coronado is one site where field biologists are studying California least tern and snowy plover populations (U.S. Navy photo by S. McLaughlin, SDZG)

As field biologists, we are lucky to have some of the most beautiful offices in the world. Every day, my coworkers and I get to enjoy long walks on the beach, warm sunshine and the occasional passing dolphin pod. Of course with views like the one in the photo, we are working alongside many other people enjoying a day at the Pacific Ocean. It’s wonderful to see people appreciating the beach habitat we all love so much, especially when it’s done in a respectful and responsible way. So, here are a couple of thoughts from a field biologist.

Both the California least tern and western snowy plover are sensitive to human disturbance. While some bird species will remain on their nest until you are very nearly upon it, terns and plovers seem to hop off at the first sign of danger. Plovers can be seen in the vicinity of the nest, performing the broken-wing display to draw perceived predators away from their nest. Terns take a more aggressive approach, screeching at and dive-bombing anyone that approaches their nest; sometimes several members of the colony will join in to drive the threat away. With the numbers of terns and plovers at critically low levels, it’s important that the birds are able to spend their energy caring for their young, instead of chasing off disturbances.


With chicks this cute and helpless, it’s easy to see why we want to protect California least tern populations. (U.S. Navy photo by S. McLaughlin, SDZG)

The most common instances of disturbance we see out in the field are people walking through the colony and dogs being allowed off leash in areas with nesting birds. In addition to upsetting the adult birds, these types of disturbances can result in trampled eggs and chicks, and stressed-out young. Luckily for all the recreational beach users out there, avoiding creating a disturbance is very easy! The most important step to take is observing and abiding by posted signs. If you are ever approached by a game warden or field biologist, don’t be afraid to ask questions. We love to talk about the terns and plovers, and outreach is an important part of our jobs!

The beaches of southern California and the birds that live there offer amazing opportunities for people to engage with nature. If we enjoy these resources respectfully and responsibly they will hopefully be here for many more years to come.


Stephanie McLaughlin is a research associate at the San Diego Zoo Institute for Conservation Research.


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


A snowy plover chick’s cryptic coloring helps it hide from predators. (Photo: Rachel Smith, SDZG at Marine Corps Base Camp Pendleton)

Well it’s finally here, SUMMER! As a born-and-raised San Diegan, I know that one thing is for certain this time of year: the beaches become a popular place to visit for some fun in the sun. Besides having to share the sometimes-crowded beaches with other humans, we need to remember that there are other animals that also live on the beach. I am fortunate to have the opportunity to work with two of those wonderful animals, the threatened western snowy plover and the endangered California least tern.

The snowy plover can be seen year round in San Diego, but the California least tern only comes to our shores during the breeding season, which is April through August. I’m sure if you’ve been anywhere near the tern breeding colonies, you will have seen these small white birds flying around like fighter pilots chasing one another and sounding like storm trooper ray guns. The plovers are small, sandy brown shorebirds with gray legs that hang out in the wrack line of kelp, eating as many bugs as they can get in their bills.


Can you spot the snowy plover chick hiding in this vegetation? Click on the image to enlarge it. (Photo: Rachel Smith, SDZG at Marine Corps Base Camp Pendleton)

During the summer at Marine Corps Base Camp Pendleton, the beaches are full of plovers and terns nesting and raising their chicks. For both terns and plovers, it takes about four weeks for chicks to be able to fly. Thus, they have to rely on camouflage to evade the eyes of predators; as biologists and monitors, this camouflage can make it challenging for us to locate them. Plover chicks are particularly good at hiding. First off, for lack of a better description, they are adorable. They look like freckled gray cotton balls with legs. Those legs come in handy when evading land predators, especially as the chicks get closer and closer to fledging (meaning they can fly). Their first defense is hiding, especially when they are young, and these little guys are experts at hide and seek.

chick revealv1

There it is! Click on the image for a better look. (Photo: Rachel Smith, SDZG at Marine Corps Base Camp Pendleton)

We are always keeping an eye out for them, looking for clues based on the behavior of the adult plovers (especially adult males) but we don’t always find them. It’s amazing how well the chicks blend into the sand and vegetation. They practically disappear and you often have to be right over them to see them. Often, our best chance of seeing the chicks when we are out monitoring is using our truck as a makeshift blind to watch for them out foraging around in the dunes and along the water’s edge. Amazingly, the birds do not perceive the truck as a threat and we can get much closer when we are inside the truck than outside of it.

Another technique we use is to blend in by staying a long distance away and using a spotting scope or binoculars to watch the behavior of the adult male (who does the rearing of the chicks) to find out where the chicks are hanging out. Watching these chicks grow up to become fledglings is a real treat, especially when I see them trying out their wings and getting a little air for the first time. It just puts a smile on my face knowing they have made it and are pretty much all grown up.

So, while I’m out with my fellow biologists doing our part to help protect these amazing animals, you as beach goers can do your part by respecting closed beach areas even when it is crowded, and keeping the beaches clean not only for each other but for all the animals that live there too. By doing this you can be a hero for wildlife and go home happy knowing that you are giving plovers and terns a safe place to grow up for future generations to enjoy.

Rachel Smith is a senior research associate at the San Diego Zoo Institute for Conservation Research.


Breeding Strategies: Secretive Plovers & Gregarious Terns

Presenting food to a mate potential  mate is part of the least tern's courtship ritual.

Presenting food to a mate potential mate is part of the least tern’s courtship ritual. (Photo: Rachel Smith, SDZG on MCB Camp Pendleton)

Both least terns and snowy plovers are ground-nesting birds that nest on barren to sparsely vegetated beaches, but they employ quite different breeding strategies. Over the past couple of months, I have been able to observe and compare these strategies while searching for and monitoring their nests.

Least terns are colonial nesters, using a “safety in numbers” approach, whereas snowy plovers use a strategy of nesting separately and being physically cryptic and secretive in behavior. Unlike the least terns, which have bright yellow bills and prominent black caps on their heads, snowy plovers have pale brown upper parts and blend in far better to their sandy surroundings making their nests less conspicuous and less likely to be discovered by predators. This also makes it much harder for us to find snowy plover nests!

If they didn't occur in such concentrations, least tern nests would be a challenge to find.

If they didn’t occur in such concentrations, the least tern’s well-camouflaged nests could be a challenge for us to find. (Photo courtesy Marine Corps Base Camp Pendleton)

On a good day my crew members and I might find about a dozen snowy plover nests, whereas during the peak of least tern nesting we can—and have—easily found over 200 least tern nests in one day! On a particularly busy day this season, we could hardly walk more than 20 feet without discovering a new least tern nest. Calling out the nest count sounded a bit like we were bidding at an auction; sometimes several nests were found almost simultaneously with one crew member exclaiming “I’ve got nest 500!” only to be quickly followed by “501!” and a few seconds later by “502!”

Because least terns nest in large colonies of up to several hundred individuals, their nests are much more obvious, but there is a lower probability of a particular individual’s nest becoming the victim of a predator. Being in a colony also offers the additional protection of having many adults present that can mob predators. Having walked through an active least tern nesting colony, I can personally attest to the protective nature of the adults. They have threatened me with their harsh “zwreep” alarm calls, flown inches from the top of my head while dive-bombing me, and even defecated on me and my data sheets in an attempt to drive me away from their nests!

Monica Stupaczuk is a research associate with the San Diego Zoo Institute for Conservation Research. You can learn more about this project by reading A Day in the Life of a Beach Biologist.


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!

The Little Green Guards were excited by our surprising camera-trap discoveries. (Photo by Lei Shi)

The Little Green Guards were excited by our surprising camera-trap discoveries. (Photo by Lei Shi)

The feeling of love and empathy for animals is very much influenced by one’s culture and upbringing. How can people conserve endangered animals if they do not love them? How do people come to love and appreciate animals? These are the kinds of questions I often ponder, and I am eager to find ways to help people, especially children, bond with animals.

Over the last five years, I have been exploring the topic of love and empathy toward animals and learning how to cultivate these sentiments in children who are in my Little Green Guards program. Little Green Guards are children living in conservation priority areas that have an underdeveloped economy and education system. The goal of the program is to build a strong and lasting love for animals in children, ultimately empowering them to become conservation stewards of their natural heritage.

Because personal experience can create deep impressions, it is important to include many field trip opportunities for Little Green Guards to fall in love with animals and nature. In Fanjingshan, China, my collaborators and I recently used our camera-trap research project as a way to introduce local schoolchildren to wildlife that may be difficult to see in the nearby forest.

Before going to the field we explained the science behind our camera-trap research to the children, how the cameras have helped us understand the “secrets” of many amazing animals, some active in the day and some at night. We then tantalized the children with our best photos and the “surprises” we discovered. The children would “Ooh!” and “Aah!” as they looked at the photos—the excitement for camera-trapping was escalating!

Fanjingshan nature reserve biologist Lei Si showed children how to mount a camera trap on a tree. (Photo by Kefeng Niu)

Fanjingshan nature reserve biologist Lei Si showed children how to mount a camera trap on a tree. (Photo by Kefeng Niu)

Out in the forest, we selected a relatively flat area with a sturdy tree. We then showed the kids how to properly install batteries and the memory card, program the settings, and finally mount the camera. When all the preparation was done, the children practiced taking “selfies,” one by one, by triggering the sensor in front of the camera and saying “Qiezi!” (the Chinese version of “Cheese!”). Beyond just having fun, this Little Green Guards lesson allowed us to teach the children not only about animal biology and caring for their wildlife neighbors but also essential life skills so they can develop healthy self-esteem, despite their rural circumstances.

Two Little Green Guards inspect the camera trap,

Two Little Green Guards inspect the camera trap,

The success of the Little Green Guards program will require long-term efforts and reaching out to as many communities as possible around Fanjingshan and other protected areas in China as well as in Vietnam and Madagascar. As the citizens who live adjacent to natural habitats form the front line of defense in protecting local biodiversity, we imagine that our Little Green Guards program may have a substantial positive influence on people’s attitudes toward conservation. We hope that one day every child in the Little Green Guards program will develop affection for wildlife so that when that day comes, we can all smile and say “Qiezi!”

Chia Tan, Ph.D., is a senior scientist in the Conservation Partnership Development Division of the San Diego Zoo Institute for Conservation Research. Read her previous post, Have Camera Trap, Will Travel.


Rocky Mountain High: Boreal toads going to a place they’ve never been before

boreal toad

boreal toad

From the window of a fancy trailer, I can see the small town of Alamosa, Colorado, and lying just behind it, the base of the Rocky Mountains. A gateway to all the many outdoor splendors that the Colorado wilderness has to offer, this small town bustles with the comings and goings of natives, as well as passers-through. However, Alamosa hides another interesting little secret. The Native Aquatic Species Restoration Facility, known as NASRF, is part of the Colorado Division of Parks and Wildlife dedicated to the restoration of 10 species of fish native to Colorado. Additionally (and perhaps more importantly for me), NASRF holds one of the largest collections of a single toad species in the US.

The southern Rocky Mountain population (SRMP) of boreal toad (Anaxyrus boreas boreas) is a geographically isolated population of the boreal toad (Anaxyrus boreas). Although the boreal toad is commonly found in the western part of the US, the SRMP is unique due to its limited geographical distribution, which restricts it to high elevations of montane wetland in Colorado, New Mexico, Utah and southeastern Wyoming. As part of a comprehensive plan to restore and manage the SRMP, a specialized group known as the Boreal Toad Recovery Team (BTRT) was established in 1995, and a captive population has been housed at NASRF since 2001. Over 600 individual toads from different localities in the wild are held and bred as a genetic assurance colony, from which tadpoles are re-introduced annually.


Alaomosa, Colorado

Amphibians are a curious group of animals. The diversity of physiological adaptations and environmental requirements makes breeding them in captivity difficult. Such is the case with the Boreal toads at NASRF.

One of the most interesting adaptations of the boreal toad is its ability to hibernate. Because they are found at high altitudes and latitudes, they have evolved this behavior to cope with long, harsh winters. However, hibernation in amphibians is not exactly the same as in mammals. In fact, the proper term for this behavior in amphibians is brumation. Like hibernating mammals, temperate amphibians lower their metabolic rates in response to falling temperatures in fall and winter. They stop eating and reduce their activity, but unlike mammals, they do not become dormant. At the beginning of spring, as temperatures rise, boreal toads come out of hibernation and immediately begin to breed.

Although temperature appears to be a key factor influencing reproduction in the Boreal toad, we are not sure how other important factors such as light and nutrition affect adult health and reproduction. At NASRF, we provide special UV lighting to emulate natural day and night cycles, a diverse diet, controlled water temperature, and artificial hibernation during the winter months. In short, we do what we can to replicate the outdoors, indoors.



In May of 2014, I made the long 1,000-mile drive from San Diego to Alamosa to join the staff at NASRF, in preparation for boreal toad breeding season. That’s not me in the photograph, that’s my trusty partner, Sancho. Seventeen hours later, we arrived at our new and very swanky home, where we would reside for the next 4.5 months. Now I guess I should explain why I told you all about the boreal toad in the beginning, and more importantly, where I fit into the picture. As I mentioned, during the winter months, boreal toads hibernate in the wild. To emulate this at NASRF we use giant refrigerators (the kind you find in restaurants). We box the little toads up with soft, moist sand and peat moss, and put them to bed for five to six months. Odd as this may seem, this period of cold is exactly what these toads need to get them in the mood for love and romance. Emerging from hibernation is like traveling to a sunny beach destination with your partner for a romantic holiday after surviving a long winter.

So, where do I come in? I am a reproductive physiologist working for the San Diego Zoo’s Institute for Conservation Research. About four years ago, I moved to the US to work on amphibians as a post-doctoral fellow at the University of Mississippi. During my post-doc, I concentrated on the application of assisted reproductive technologies to promote reproduction in captive amphibians. When natural matings occur in boreal toads we expect to see certain reproductive behaviors, such as males amplexing females. This clasping behavior may persist for days while the male stimulates the female to deposit her eggs. When breeding does not occur or a female fails to release eggs naturally, I inject females with hormone treatments designed to elicit egg deposition. I also use the same hormones to induce sperm production in males.

Boreals amplexing

Boreals amplexing

Like in humans, ultrasound helps us monitor female toad reproductive cycles by visualizing the ovary and determining the presence and size of eggs. This helps us know if a female that has not bred is ready to deposit eggs. If so, I would inject her with hormones. Once eggs have been deposited, we count the number of eggs that have been fertilized and are cleaving (dividing). Embryonic development is recorded by looking at embryos every day and cataloging different developmental stages.

We raise tadpoles in captivity until they reach a certain size and have developed back legs, before transporting them to the Rocky Mountain National Park for release into the wild. This final stage of the adventure is managed and monitored by the dedicated staff at NASRF and the National Park. Saving the SRMP boreal toad is a collaborative project, with the ultimate goal of restoring these animals in their natural habitat.

(I’d like to thank all the staff at the Native Aquatic Species Restoration Facility for their help).

Natalie Calatayud is a research associate at the San Diego Zoo Institute for Conservation Research.