camera traps


What Might Monkeys Be Up To?

The Guizhou snub-nosed monkey’s night life was a secret until recently.

The Guizhou snub-nosed monkey’s night life was a secret until recently.

February 10 marks the beginning of a new year, the Year of the Snake, according to the Chinese lunar calendar. I cannot help but reflect on what I have done in the past year and contemplate what I wish to accomplish in this new year.

Last year, my research project focused on an investigation of wild Guizhou snub-nosed monkeys in China using camera traps. This work was conducted in Fanjingshan National Nature Reserve (FNNR) in collaboration with the reserve’s administration. We set up a network of over 100 camera traps to monitor, in addition to the Guizhou snub-nosed monkey, many hard-to-see wildlife species in the reserve (see post Monkeys, Leopard Cats, and Bears, Oh My!,). Some of our unexpected captures were images of Guizhou snub-nosed monkeys moving about in the middle of the night (see article in Primates). Although these monkeys are considered daytime active species very much like humans, our camera-trap data provided unequivocal proof that they are routinely active after dark. What might the monkeys be up to?

Guizhou snub-nosed monkeys’ nocturnal habit, we believe, is motivated by the need to acquire as much food as possible. In other words, the monkeys are up at night because they are hungry. To some people, this discovery may seem like a non-discovery, but many great scientific discoveries are inherently simple, and they often start out with a simple observation, like the apple that fell on Newton’s head. But I digress, back to the monkeys.

An important outcome of our camera-trap study, besides showing the behavioral flexibility the monkeys have to cope with living in a highly seasonal environment, is the need for researchers to rethink methodological designs that minimize observer bias. If we habitually observe diurnal primates during the daytime we, of course, have data that only show them being active during the hours we observe them. Camera traps, therefore, are excellent devices to augment our data collection. And, because of the amount of photographs we have, you can count on me spending much of my time this year uncovering more secrets about the animals in Fanjingshan.

My research collaborators, from left: Duoying Cui (Beijing Zoo), Marco Gamba (University of Torino), me, Yeqin Yang (FNNR), and Kefeng Niu (FNNR)

My research collaborators, from left: Duoying Cui (Beijing Zoo), Marco Gamba (University of Torino), me, Yeqin Yang (FNNR), and Kefeng Niu (FNNR)

An intrinsic part of what I do as a scientist is to assist students with their professional development. Through mentorship of students, I help foster future colleagues and, in turn, expand my network of collaborators. This past year several of my students completed their research thesis, attained a higher degree, received scholarships, and/or launched new projects. James Dopp is a graduate of the University of Vermont who worked with me in Fanjingshan in 2010 through 2012. He has been awarded a Fulbright Fellowship to further sharpen his research skills in primate conservation in China.

Kefeng Niu, a resident biologist of FNNR, continued to benefit from my coaching. In August, he successfully delivered a paper in English at the International Primatological Society Congress. The Congress also provided Kefeng a chance to meet other professionals, among them, Dr. Marco Gamba, my Italian colleague from the University of Torino. I introduced Marco and his research on primate vocal communication to Kefeng. We later invited Marco to join us in Fanjingshan to resume our wonderful discussion about snub-nosed monkey biology with China’s renowned primate expert, Yeqin Yang (see post Saving Monkeys Takes a Team). And the rest, as they say, is history, because when Marco left Fanjingshan, he had already signed a five-year research agreement with the reserve administration and gained a prospective PhD student, Kefeng Niu. Mama mia!

Cameron makes her debut as “Yi Jie Jie”

Cameron makes her debut as “Yi Jie Jie”

Recently, my mentorship pool of students included a junior from High Tech High International. Her name is Cameron Ishee, and though only 16, she is well on her way to transforming how people perceive and treat animals. Because of Cameron’s ability to speak Chinese (Mandarin), I asked her to help me create a series of bilingual video lessons for the children in the Little Green Guards program in Guizhou (see post March of the Little Green Guards). Each episode stars Cameron as Yi Jie Jie (or Big Sister Yi) teaching an English alphabet letter and about half a dozen animal-related words associated with the featured letter. To make learning memorable and fun, we segue from the classroom lessons into video segments of our Zoo and Safari Park animals. In doing so, we are achieving several objectives: introducing a world-class animal collection to underprivileged children who would otherwise never have the opportunity to travel to San Diego, and enhancing the school curriculum by teaching these children a highly valued foreign language that only children living in the more affluent urban areas of China are learning.

Our pilot episode is almost complete. Cameron and I will continue making more episodes this year. Just a little spoiler alert here, snake will be featured in our upcoming episode: “S is for Snake.”

Chia Tan is a scientist in the Behavioral Biology Division with the San Diego Zoo Institute for Conservation Research.


Monkeys, Leopard Cats, and Bears, Oh My!

Wild Guizhou snub-nosed monkeys "caught" by the camera trap.

“Follow, observe, and record,” was the first directive I learned starting out as a field primatologist. For years I did exactly that; all day long in Madagascar, from the moment the lemurs awoke before sunrise till they retired at the end of the day after sunset. And I took great pride in my ability to habituate these primates, follow them up and down mountain slopes through dense vegetation, and observe and record their behavior with just a pair of binoculars, a notebook, and a pen.

An Asiatic bear cub follows its mother.

This simple standard methodology, though it can be successfully applied to studying many primate species, is not well suited for snub-nosed monkey research in China. Why? Free-ranging Chinese snub-nosed monkeys are notoriously difficult to follow because they live in groups containing hundreds of individuals and are not tolerant of human observers. Also, unlike most primate species that inhabit tropical environments, these monkeys range into the temperate zone in areas where snowfall occurs four to five months of the year. In other words, collecting behavioral data on free-ranging Chinese snub-nosed monkeys through direct observation was a tremendous challenge for researchers, until recently.

Tibetan macaques

Last year my colleagues at Fanjingshan nature reserve and I began using camera traps in our research of the Guizhou snub-nosed monkey (see post Saving Monkeys Takes a Team). And as you can tell by the title of this post, the captured images included not only the Guizhou snub-nosed monkey but also another rare macaque species, the Tibetan macaque, as well as leopard cats, bears, and other elusive mammals, indicating the reserve still harbors a rich community of wildlife! We are in the process of sorting through thousands of camera-trap images, but I’ve included some exciting examples here.

Leopard cat

Indeed, “A picture is worth a thousand words,” and these images convey much information about the behavior of wild animals. However, we need to be mindful that camera traps are tools for collecting supplemental data; they cannot be used to replace researchers. It is important for researchers to spend quality time with their study animals in the field to obtain data firsthand that provide the contextual information necessary for the observed behaviors. All those years of me running after lemurs and monkeys in the forest, therefore, was not done in vain. Through direct observation, I have gained an understanding about primates in situ.

This understanding has helped me interpret the camera-trap images and infer the motivations of the monkeys’ behaviors in a biologically meaningful way. I must admit I was not a huge fan of camera-trap technology initially, but I am thoroughly impressed with the images captured so far. I give it a “thumbs up!”

Chia Tan is a scientist with the San Diego Zoo Institute for Conservation Research.


Missing Camera: The Work of a Bear?

The view from the forest near where a camera trap vanished.

At the end of the calendar year, many people think about how to manage their finances to avoid a big tax bill. Well, the Andean bear program just paid a necessary cost to operate a network of camera traps in the cloud forest. I think of it as a tax to Mother Nature, or as she might be thought of in the Peruvian Andes, Pachamama.

In spite of hours of searching effort, it appears that the cloud forest has swallowed a camera trap, perhaps with a little help from an Andean bear. When we set cameras in locations we believe to have a high risk of theft or vandalism, we lock the cameras to the trees. However, this camera was in a remote spot and so was not locked down. The cord used to tie the missing camera to the tree was found snapped and lying on the ground, and there were scratches on the tree, but the camera was gone.

The only route for humans into and out of this site is along our transect of camera traps, and the other cameras did not detect any humans in the area. These facts suggest that the camera was removed from the tree by a wild animal; although some animals sniff the cameras, bears are the only animal we’ve ever detected moving a camera around on a tree. So, my best hypothesis is that a bear pulled the camera down from the tree and either knocked it down the densely vegetated slope or carried it away.

Over 18 months ago, we lost a camera to natural causes at another site when a landslide tore down the hillside and blasted a path through the forest that was about 65 feet (20 meters) wide and almost 1,000 feet (300 meters) long. Unfortunately, the landslide also blasted away the tree to which a camera was tied.

If we’d been able to find either of these missing camera traps, I bet we’d have recovered some interesting photos! As it is, I guess one camera per year is the tax we’re paying Pachamama to work in the cloud forest.

Russ Van Horn is a scientist with the San Diego Zoo Institute for Conservation Research, leading our Andean bear conservation program. Read his previous post, Andean Bear Sightings.


Andean Bear Sightings

Dimples in the sand show where Russ' sweat droplets landed.

As I stepped up onto the ledge and looked down the rocky trail, I realized that I needed to take a break. It was just too hot and dry for me to keep up with Javier and Isai, two parabiologists from the Spectacled Bear Conservation Society. We still had enough time to reach camp before it became too dark, so I stopped to catch my breath. As I stood there huffing and puffing, I noticed some dimples in the sand below me. It hadn’t rained for a long time, so what liquid could have fallen and created those dimples? After puzzling for a moment while looking down, I saw the answer as sweat dropped off my chin and fell to the ground: those dimples were made by me as I stopped in the same place to rest before dawn that day! We had walked up the trail while it was still dark, in order to be in a hiding place before dawn. We had then waited all day to see if and when an Andean bear (aka spectacled bear) would come to the waterhole.

Rinds left after an Andean bear fed on a sapote fruit

Most of the year this type of effort would be a waste of time. However, when the sapote fruit is ripe down in the valleys, the local bears often walk down from the hills to feed on sapote during the morning before returning to the hills before dark. On their way uphill, they often stop for a drink of water at one of the rare waterholes. Our most predictable opportunity to see a bear, and place a GPS transmitter on it, comes when we move in a pattern opposite to the bears and intercept them at the water.

A wild female Andean bear and her cub

As we walked to and from the waterhole for several days in a row, we saw evidence that bears were in the area. Sometimes we’d see partial tracks of bears, or else the rinds that bears leave behind after eating sapote fruit. Even better, we saw at least one bear on each of the nine days we spent waiting at the waterhole! Usually these were the same few bears, so in total I think we saw four different bears; twice the bears were too far away to identify with any certainty.

We saw the same female bear and her nearly independent cub come to the waterhole on eight of the nine days. This female’s behavior was different from that of females with very young cubs, which appear to avoid the waterholes as best as we can tell from data from GPS collars, camera traps, and direct observations. Perhaps mothers with young cubs act differently because their cubs cannot walk very far, or perhaps mothers with young cubs wish to avoid encountering adult male bears; we’ll need more data to better assess these two hypotheses. Meanwhile, I’m glad we have the opportunity, and the skilled field team, to collect those data. It’s also rewarding to see the bears!

Russ Van Horn is a scientist with the San Diego Zoo Institute for Conservation Research, leading our Andean bear conservation program. Read his previous post, Camera Trap: Bush Dogs.


Little Fruit, Thin Bears

This is a camera trap photo of the female Andean bear Magaly on December 7, 2009, when she was thin and in poor condition, before many ripe sapote fruit were available.

It was about 16 months ago when I first saw an Andean bear in the dry forest of Peru during the Southern Hemisphere winter. When I did, I was shocked. As this bear walked down the hillside toward a waterhole I could count her ribs, I could see her backbone, and I could watch her hipbones moving. Her fur was dull, and I could hardly believe how bad she looked. My colleagues had told me that the bears living in the dry forest were thin during the winter because there wasn’t much for them to eat, but I didn’t know the bears became THIN! The only other wild bear I have ever seen so scrawny was an American black bear I encountered many years ago in southwest Montana; that bear had become dependent on food it obtained from people, and it began starving when it no longer had access to the supplemental food.

This is a camera trap photo of the same female Andean bear, Magaly on April 29, 2011, after she’d become plump by feeding on sapote fruit.

When I expressed my concern over the skinniness of the dry forest bear to the field team of the Spectacled Bear Conservation Society (SBC), they told me that they had seen bears in the dry forest that looked even worse than the bear I was watching but that had nevertheless survived. In reality, I was shocked only because I didn’t have much experience in the dry forest; that bear was not unusual. She not only survived, but she mated a few months later and is now raising a young cub. Skinny dry forest bears look shocking to people who don’t have experience in the dry forest, but in fact their weight loss is part of a natural cycle that becomes obvious to anyone who studies dry forest bears for more than a year.

This is a portrait of nearly ripe sapote fruit still on the tree when there were ripe sapote fruits lying on the ground beneath the tree, and when bears were foraging on sapote fruits. We hypothesize that fruits like this one are critical for the survival of individual bears, and the bear population, in the dry forest.

Working with SBC in the dry forest, we’ve accumulated evidence over the last several years that Andean bear movements and body condition are linked to a species of tree, the sapote. Evidence from direct observations, camera traps, and satellite telemetry collars all suggests that bears focus their movements and foraging on sapote fruit when it is available, which is usually only for two to three months just before the annual rainy season.

After ripe sapote fruit become available, usually beginning in late November, the bears’ body condition improves noticeably, so that within a few weeks the bears no longer look like walking skeletons. After a few more weeks of feeding on sapote fruit, the bears start to look a little plump, although they never get as fat as American black bears and brown bears do in autumn. During the rest of the year when sapote fruit is not available, Andean bears in the dry forest gradually lose weight so that they are skinniest just before the sapote fruit is ripe. These observations strongly suggest that healthy populations of sapote trees are critical for the health of individual Andean bears in the dry forest and for the health of the dry forest bear population. The sapote tree is considered critically endangered by the Peruvian government, so we’re promoting conservation of sapote trees as part of the Andean bear conservation program.

A camera trap photo shows male Andean bear Russ on December 5, 2009, when he was thin and in poor condition before many ripe sapote fruits were available.

This is a camera trap photo of the same male Andean bear, Russ, on March 21, 2011, after he’d gained weight by feeding on sapote fruit.

The field team is seeing something unusual right now that may answer a question that’s been puzzling me for over a year. Young cubs and subadult bears often disappear when their mothers are skinniest, shortly before the sapote fruit ripens. We suspect that, unfortunately, when adult bears have a hard time finding food, many young bears do not survive. If that happens year after year, how can the population of bears in the dry forest remain stable? This year some sapote fruits are ripe earlier than normal, and some bears are starting to gain weight earlier than usual. This makes us hopeful that this year more cubs and subadult bears will survive. Of course, the survival of youngsters may depend on what the sapote trees do over the next few months, which reminds me of other questions we have. Why do sapote trees produce fruit when they do? What influences how many sapote fruits are produced? There has been a little research done on these questions, but we’ve still got some work to do to fill in the blanks!

Russ Van Horn is a scientist with the San Diego Zoo Institute for Conservation Research, leading our Andean bear conservation program. Read his previous post, Mountain Lions and Palm Trees.

For more information about the seasonal fluctuations in resources such as sapote and the need to conserve them, see posts Dry Forest Bears of Peru and To See a Bear.


A Summer Spent Helping Kangaroo Rats

Matt modifies a camera trap to reduce temperature impacts on the camera.

I was lucky enough to work as an intern this summer for the Applied Animal Ecology Division of the San Diego Zoo Institute for Conservation Research. Starting work in late June, I did not know what to expect. Over the course of this summer, I’ve been involved in everything kangaroo rat, from nightly trapping to building little “kangaroo rat homes” on their translocation sites. I’ve had a blast this summer and have learned a great deal about conservation biology and the protection of local species.

Coming into this project, I knew I wanted to work for the protection of local endangered species, and Stephens’s kangaroo rats (SKRs) seemed like a perfect fit. Growing up in suburban San Diego, I had seen very little local wildlife. I was astonished to find out the number of vulnerable and endangered species here in our own county. Working with Debra Shier and Maryke Swartz this summer, I was able to aid in endangered species research and understand the local biome that I had always been acquainted with but never truly known.

Matt checks a trap, hoping to find an SKR.

I spent the majority of the summer working on a project that sought ways to deter predators from kangaroo rat translocation sites (see SKRs Get TLC). “Translocating,” or moving animals from unprotected lands to protected areas within the reserve, is one of the major components of protecting SKRs. Increasing survivorship on these translocation sites is equally important. Previous research conducted by Debra pointed to increased survivorship of SKRs on sites that had been marked with mountain lion, or cougar, urine (see post, Kangaroo Rats Dig Mountain Lions!).

She believed that the mountain lion urine could be deterring SKR predators from visiting the translocation sites. I was asked to conduct a three-week study, testing this hypothesis. I set to work conducting a field study analyzing the effects of mountain lion and wolf urine on the deterrence of natural predators of the Stephens’ kangaroo rat. To visually observe these effects in the field, 32 camera traps were set up on different portions of the reserve with urine placed in front of the cameras. These cameras have both still image and video recording capability, invaluable for recording visitation to the sites and behavioral responses of the predators as well.

Matt installs an acclimation cage for this year's translocation effort.

Initially, I did not expect a great number of animals to be recorded by the cameras. Debra assured me that many predators would indeed be captured on the cameras. She was right. Being a San Diego native, I found growing up that seeing the natural predators of the region was an uncommon occurrence. Coyotes would occasionally scamper across the road late at night, skunks and raccoons rarely appeared, and I had never seen a wild bobcat in San Diego County. To my surprise, at the reserve in Riverside County I experienced a total of 142 predator visitations to my 32 sites over the course of 3 weeks.

After analyzing the data from the study, we found that mountain lion/cougar urine does indeed have a significant impact on coyotes, the principal ground predator of the SKR. Although initially drawn in by the scent, the coyotes are subsequently strongly deterred from visiting sites marked with mountain lion urine. This was in strong contrast to the wolf urine treatment, which seemed to attract more animals as the study continued on. From this information we have gathered that to successfully deter coyotes from translocation sites, mountain lion urine should be placed around the site at least four days in advance to SKRs being released onto the site. This way, coyotes will be effectively deterred, and this will minimize predation on the translocated SKRs. The chart below show the average visitation of coyotes at the remote camera stations with the four scent types: cougar (mountain lion), wolf, deer, and water.

Besides my work on the experiment this summer, I also had the privilege of working actively for SKR conservation. Debra told me that my work this summer was going to be as half-biologist, half-construction worker. Boy, was she right! At times, I felt like a professional biologist, donning my headlamp and trapping SKRs through the night. Other times, I felt construction “worker-esque,” digging holes alongside a prison crew for SKR acclimation cages. Throw in some arts and crafts (making cages, camera boxes, and anything else that we needed for the project), and I could call it a productive summer.

A coyote visits a remote camera station.

For me, I could not have asked for a better experience to start my career in field biology. Growing up as a kid in San Diego, I always wanted to work with the San Diego Zoo. This job was truly a dream come true. The valuable lessons that I have learned here I won’t forget and will aid me as I continue my career.

Matt Golembeski was a summer fellow for the San Diego Zoo Institute for Conservation Research. Thank you, Matt, and good luck to you as you continue your career goals!


Burrowing Owls: Closer than You Think

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