About Author: James Sheppard

Posts by James Sheppard


Space, The Final Frontier for Conservation Research

Miniaturized and “ruggedized” field computers enable data to be collected accurately and consistently directly from the wild.

Spatial ecology, the fastest-growing field of study in ecology, is a powerful approach to understanding how ecosystems function and the ways populations and communities of species interact with their environment. We can utilize spatial ecology to study the resource-patchy natural world. Landscapes are not uniform like a chessboard or still like an oil painting—nature changes everywhere and every time you look at it. For instance, grass in a park may have patches where water encourages the plants to grow in denser and lusher clumps than in other drier parts. It also changes with the seasons and the ways it is used by other animals. In other words, natural landscapes and the organisms that inhabit them form patches that are distributed through space and time in different and interesting ways. Ecologists study the underlying causes of this patchiness to better understand the patterns, processes, and dynamics that lead to specific spatial arrangements of wildlife and habitats. Spatial ecology is all about the “where” and the “why” plants and animals use their landscape.

Rapid advances in technological developments are enabling ecologists to open previously unimaginable windows into the behaviors of free-ranging animals that would be impossible or extremely difficult to study directly in the wild. For example, miniaturized digital tracking devices enable us to safely track wild animals, from Hummer-sized elephants to the diminutive Pacific pocket mouse, remotely and at high-resolution for extended periods without interfering with their behavior or well-being. Where once biologists had to sit patiently on a mountain cliff in the hope of catching a rare glimpse of a California condor through a pair of binoculars, GPS transmitters attached to the wings of reintroduced condors now enable us to continuously track these magnificent birds as they fly vast distances throughout their range.

GPS tracking collars, satellite imagery, and GIS software have enabled us to identify the seasonal home ranges of wild giant pandas tracked within their mountainous bamboo habitat in China. Here, the home range of young male panda Xiyue is delineated into its winter range in the low valleys (left) and summer range in the high peaks (right). The ranges are overlaid across a 3-D elevation map, with brighter colors within the ranges indicating areas that have been used most often.

Orbiting satellites that were previously only used for military intelligence and resource extraction purposes now have enormous application for conservation research. Satellites can acquire extremely high-resolution images of entire landscapes. These “remote sensing” data can then be spatially analyzed to identify the characteristics, processes, and patterns of wildlife habitats. Scientists previously had to directly measure wildlife habitats in the field using samples, photographs, and tape measures, which usually took a long time and could be conducted across only small areas. The power of remote sensing enables satellite images to be analyzed rapidly and accurately across great stretches of time and space. For example, we can monitor how the Arctic ice sheets that comprise habitat for threatened populations of polar bears are changing over time. We can also analyze satellite images of the Amazon rain forest to characterize tree canopy structure and identify regions experiencing habitat destruction. In fact, these new spatial technologies are providing so much high quality data that a new term called “data toxicity” has been coined to describe how researchers can be overwhelmed and literally fail to see the forest for the trees!

We now have a dedicated facility to conduct cutting-edge spatial research to enhance the conservation management of endangered species and habitats in the U.S. and around the world. Thanks to a generous donation from the Ellen Browning Scripps Foundation, a Spatial Ecology Lab is now in place at our Beckman Center for Conservation Research. This will enhance the work being done in all of our divisions and benefit plants, animals, and even the gene flow of populations.

Our new lab is equipped with high-powered computer workstations, state-of-the-art geographic information system (GIS) software, and digital field devices. The software available in the lab is top-level industry standard and was generously provided to the Zoo at substantial discount by the vendors. The lab will enable us to collect, process, and analyze enormous and highly accurate spatial ecology data sets to build detailed pictures of animal habitat use and requirements. We will also be able to map local and international threatened landscapes and habitats in great detail and identify how they change over time as a consequence of human disturbance.

The much-needed Spatial Ecology Lab will ensure that the San Diego Zoo Wildlife Conservancy maintains its technological edge and leadership role in the global conservation of endangered species and habitats.

James Sheppard is a research fellow at the San Diego Zoo Institute for Conservation Research. Read his previous post, “Carrion” Research to the Next Level.


“Carrion” Research to the Next Level

James holds a California condor egg produced in the wild.

I have been on the trail of the California condor for some years now. And what a trail it is, from shimmering cactus-studded deserts baking under the relentless hammer of the Mexican sun to the desolate jagged beauty of the Sierra Mountains to the ancient alpine forests of northern Baja California, Mexico, crystallized beneath a silencing white shroud of fog and snow. These are the worlds that this mighty vulture surveys from on high with its enormous black wings, extraordinary eyesight, and an inquisitive and engaging intelligence.

As remarkable and inspiring as the condor and its wild domain are, so too are the heroic efforts of San Diego Zoo Global and its many dedicated partners that have struggled for decades to haul this unique species back from the abyss of extinction. And from a population of just 22 birds at their lowest ebb in the 1980s, this year we have reached a landmark 400 wild and captive condors.

I joined the San Diego Zoo Institute for Conservation Research to provide vital information on the social behaviors, movement patterns, and habitat requirements of the condors that we are reintroducing to their former range in Baja California. Collecting data on free-ranging condors is notoriously difficult. Fortunately, I am equipped with the latest cutting-edge technologies that have opened an unprecedented window onto condor behaviors within their natural environment.

A GPS device attached to the condor's wing provides researchers with valuable information about the bird's flight patterns.

Miniature GPS devices attached to the bird’s wings continuously acquire and transmit data on their flight patterns. An array of weather stations positioned throughout the condor’s range provides detailed information on the meteorological conditions that influence their movement. Analysis of satellite imagery and digital topographic models of the condor’s environment enables me to construct a detailed picture of their habitat use and requirements.

Remote video cameras installed at condor feeding stations allow me to observe and analyze their social interactions without having to wait in the field or disturb the birds with my presence. The science of ecology is being driven by these examples of technological advances, and San Diego Zoo Global prides itself on being a leader in the application of state-of-the-art techniques for conservation research.

My studies have confirmed that condors range hundreds of miles in a single day while exploring and searching for food carcasses and that these flights are typically conducted by subadults before they settle into core home ranges. Condors are able to fly for long periods without expending much energy by harnessing the strong thermal winds generated by mountains and ridgelines to soar with the efficiency of an albatross. Condors also possess a remarkable spatial memory map, returning from long-distance flights directly back to their communal roosts.

There is still hope for this magnificent bird.

I have found myself amazed by condor curiosity and playfulness, as well as the complexity of their tight-knit society. Birds that do not develop appropriate social behaviors at an early age do not successfully integrate into condor society, and such ostracism results in their early demise from predation or starvation. By characterizing the dynamics of condor “pecking orders,” I have determined which attributes confer high or low dominance status. I have learned that each bird has a personality, and condors act much like human teenagers and politicians—continuously jostling and squabbling for rank, resources, and respect.

Some have argued that disproportionate levels of resources are directed toward condor recovery. Indeed, after a field season of freezing temperatures, putrid carcasses, and obstreperous equipment, I have on occasion questioned my own involvement. However, when you stand on a mountaintop or a canyon and this magnificent buzzard with its 9-foot wingspan suddenly swoops over you and completely owns the sky, all sense of doubt immediately evaporates and is replaced with awe, admiration, and hope—hope for the survival of the species and hope that future generations will also have the opportunity to experience condors in the wild. In an age of extinction and loss, the condor is a vital link to our increasingly diminished ecological heritage, an iconic expression of evolution’s genius, and a much-needed example of a conservation success story.

James Sheppard is an ecologist at the San Diego Zoo Institute for Conservation Research. Read his previous post, Wild Condor Chick Gets Own TV Show.

View our own California condors on our new Condor Cam!


Wild Condor Chick Gets Own TV Show

A California condor watches over his chick in the family's cave in Baja California, Mexico.

Recently, conservation scientists and managers from San Diego Zoo Global’s California Condor Recovery Team successfully installed an autonomous video camera system inside the cliff-face nest site of our new wild-hatched condor chick in Baja California, Mexico—for the very first time! This high-tech field video system consists of a tiny, low-light, weatherproof camera that sends images via cable to a separate recording box equipped with a memory card. The batteries powering the unit are constantly recharged by a portable solar panel, so once the unit is set up, it can record video footage for weeks at a time. We acquired the video recording unit through a generous grant provided by Judy Wheatley, a member of the Zoo’s board of trustees.

Okay, great, so you have a neat video camera – but how do you install one in a condor nest high up in the mountains? With a lot of sweat, grunt-work, and no fear of heights!

I acquired and set up the unit and transported it to the condor nest site with the assistance of program manager Mike Wallace and Mexican field staff Juan Vargas and Mohamed Saad. To minimize disturbance to the condor family, the camera installation trip coincided with the condor chick’s scheduled health exam and vaccination, so also present were the highly experienced and capable vets Jeff Zuba and Fernando Sanchez.

Early on a very hot Baja summer’s day, our team set off to inspect the chick and install the video camera. With pounds of scientific and veterinary equipment strapped to our backs, as well as climbing rope and gear and plenty of water, we slowly and carefully wended our way down a steep, cactus-covered scree slope toward the nest. The chick’s parents had chosen their real estate well, and it took us many hours of hard slog just to get to the top of the cliff where the nest was located. The chick has a spectacular view that looks out across a mountainous vista covering remote valleys and ranches all the way to the Pacific Ocean.

At the staging site, we set up our equipment in preparation for the descent into the nest and the health inspection. While the chick was being examined and vaccinated, Juan rappelled with the camera down into the nest and bolted it into the roof of the cave. The resulting panoramic view of the nest now enables us to monitor the chick’s development as well as the behaviors of its parents. In this short video clip, you can see the chick’s proud dad (condor #269) in the foreground. The chick then pops up behind him and flaps its short, stubby, developing wings. The video is in black and white because the camera is specialized for extremely low-light conditions, such as those experienced inside a cave.

The condor program has its fingers crossed that this chick will successfully fledge and make its first flight out of the nest in the coming months to join our wild condor population. This is just one example of how modern technology and scientific research is improving the San Diego Zoo’s ability to effectively manage and expand the reintroduced condor population in Mexico.

James Sheppard is an ecologist at the San Diego Zoo Institute for Conservation Research. Read his previous post, Measuring Wind beneath Condor Wings.


Measuring Wind beneath Condor Wings

A condor's eye view? Flying over condor habitat in Baja California, Mexico.

A condor's eye view? Flying over condor habitat in Baja California, Mexico.

Last month, we conducted an expedition to install a series of meteorological stations on the remote and inaccessible eastern escarpment of the Sierra Mountains of Baja California, Mexico. This rugged region of spectacular natural beauty is the release site for the San Diego Zoo’s California condor reintroduction program. This site was chosen because of its status as a pristine, protected area of the condor’s former range. Condors existed in the mountains of Baja until they disappeared in the 1940s, only to reappear in 2002 when the San Diego Zoo released captive-bred birds back into their former habitat.

The mountainous terrain of the Baja reintroduction site provides ideal habitat for the wild condors. The birds must range over extremely wide areas to detect the carcasses of the animals that they scavenge upon for food, such as mountain sheep, goats, and pigs. California condors are extremely efficient fliers, and they are able to glide for long distances without flapping their wings, much like an albatross does when flying across the open ocean. This efficient soaring enables the birds to successfully search for food without expending too much energy. Condors gain lift by catching thermal updrafts, and these wind currents often form alongside mountains. Thermal winds are especially frequent along the Baja Sierra ranges, when warm air from the valleys and deserts below forms a rising column. The strong winds and frequent thermals that occur in this area make it an ideal location for condor habitat, and the birds have been tracked making long-distance exploratory flights whenever wind conditions seem to be suitable.

Defining suitable (or even optimal) wind conditions in condor habitats is key to successfully managing wild condor populations and reintroduction programs. The importance of wind in determining condor foraging success means that a habitat that may seem ideal to conservation managers (i.e., due to high densities of food items or good roosting and nest sites) may actually be inferior in the eyes of a condor because the winds are too weak, erratic, or unstable to sustain efficient condor flight over long distances. In fact, the condor population that was released by the Zoo on the western escarpment of the Baja Sierras now makes frequent and unforeseen use of the eastern ridges 12 miles (19 kilometers) away, where strong, hot winds roar up from the scorching Laguna Salada desert below.

One of the remote-operated meteorological stations the author helped install.

One of the remote-operated meteorological stations the author helped install.

To gain a better understanding of the climate conditions that drive condor movement patterns and modify condor habitat preference, we installed remote-operated meteorological stations within the range of the released condors. These stations are solar-powered and mounted on 10-foot-tall (3-meter-tall) tripods. A logger records climate information from wind and air temperature sensors, and these data are then transmitted via a satellite phone network. This way, the stations can be installed in remote areas without the need to change batteries or download the data by hand, as the climate sensor information can be directly downloaded from the Internet.

A precarious perch for the helicopter!

A precarious perch for the helicopter!

The eastern escarpment of the Baja Sierras favored by the wild condors is so steep, rugged, and remote that it is inaccessible by foot. Hence, we had to employ a helicopter to install our meteorological stations (with the kind permission of the Mexican federal government, the local ejido (community), the management department of the Parque Nacional Sierra San Pedro Martir, and the Mexican military). After loading up the chopper with our scientific equipment at San Felipe airport, we flew directly across the desert and high up into the mountains. I had previously determined the location sites for each station using the combined home ranges of the birds themselves: that way, we would be collecting climate data within the areas that the condors actually use. These locations proved to be so steep and jagged that our expert pilot had to search hard for safe landing sites. Often we had to land on the edge of sheer precipices with the chaparral barely feet away from the spinning helicopter rotors!

Another typical day at the office...

Another typical day at the office...

As soon as we had set down safely, we rushed out to erect each tripod by bolting it onto the top of a flat rock; the incredibly strong winds that occur in the area mean that each station must be robustly secured. Setting up and activating each station took less than an hour, and we had successfully installed each unit by early afternoon. Upon our return, we were able to immediately begin downloading the climate data recorded by each station at five-minute intervals. These highly accurate, high-resolution data will provide invaluable information on how wind patterns shape and modify the movement patterns and habitat use of the reintroduced condors. This information will in turn help managers fine-tune the condor reintroduction program to the specific habitat requirements of this endangered, iconic species.

James Sheppard is a postdoctoral fellow for the San Diego Zoo’s Institute for Conservation Research. Read his previous post, Condors: Quest for the Egg.


Condors: Quest for the Egg

Female condor #284 enters her nest.

Female condor #284 enters her nest.

April has been a very busy and exciting month for the San Diego Zoo’s California condor project. Condor field managers and researchers have been using VHF and GPS telemetry to closely monitor the movement behaviors of the birds that have been reintroduced to Baja California, Mexico. Early spring is the condor breeding season, and we hope to observe breeding and nesting behaviors that will lead to successfully fledged chicks this year.

Condor Field Manager Juan Vargas rappels down the cliff face to a condor nest.

Program Field Manager Juan Vargas rappels down the cliff face to a condor nest.

Two pairs of condors are currently exhibiting breeding behaviors within the reintroduction site in Sierra de San Pedro Martir National Park in the northern Baja peninsula. The first condor pair, comprising birds #217 and #261, is nesting about 10 miles (16 kilometers) east of the reintroduction field station among the soaring, jagged peaks overlooking the desert toward the Gulf of California. The second pair, comprising birds #284 and #269, is guarding a nest site only a mile (1.6 kilometers) from the condor field station in the middle of a steep cliff face on the western, Pacific side of the Sierra ranges. These condors laid an egg in the same nest last year but, unfortunately, it was infertile. The field staff decided to conduct another inspection of this nest to determine whether the pair has laid a viable egg in the wild this year.

A condor egg in the nest.

A condor egg in the nest.

The nest site that condors #284 and #269 have chosen is isolated and well concealed from potential egg raiders such as bobcats and ravens. However, this meant that to access the nest we had to carry climbing equipment along the steep edge of a granite scree slope before program field manager Juan Vargas could make an extended 330-foot (100-meter) rappel in three stages from the top of the cliff down into the nest entrance. Juan found that these condors had indeed laid another egg within this nest. Using a powerful flashlight, Juan was able to candle the egg and determine that this time it was viable. During the candling process, the female condor #284 soared back and forth in front of the nest before landing on the ledge outside (see photo at top), entering and regurgitating her last meal all over Juan’s boots! This defensive, anti-predator behavior is actually an encouraging sign that the birds are determined to guard their nest and are therefore good breeders. Further nest entries will be conducted in the near future to determine the health of the condor chick once it hatches, inoculate it against avian viruses, and attach transmitters before it takes to the air for the first time.

After the western nest inspection, the field team traveled to the mountain ranges on the eastern side of the Sierras to search for the nest of condors #217 and #261. This trip took us across the parched lakebeds and deserts inland from the coastal tourist town of San Felipe toward the imposing mountains of Picacho del Diablo. At 10,000 feet (3,000 meters), these are the tallest peaks in Baja. Camped among the giant cardon cacti at the base of the mountains, the field team is now sweeping the area for the VHF signals broadcast by microtransmitters attached to the breeding pair. Once the location of the condor nest is confirmed, an expedition will be conducted to enter the site and inspect the (hopefully healthy) egg that lies within.

While based at the feet of the eastern ranges during the search for the second condor nest, we also installed the first of a series of meteorological stations on top of one of the nearby peaks. Hauling the station and the heavy equipment needed to install it up steep, spiny, cactus-covered slopes during 108 degree Fahrenheit (42 degrees Celsius) heat in the shade proved to be a challenging endeavor, and we greatly appreciate the assistance of the local Mexican neighborhood at Rancho Santa Clara. This meteorological station is currently transmitting data on wind speed and direction plus the temperature of the air at the eastern mountains for download via the Internet. These data on the climate conditions experienced by the condors in the region are providing valuable information on the environmental variables that determine the habitat preferences of the birds. Condors make extensive use of the strong winds and thermal updrafts that occur across the face of mountain ranges to make long-distance foraging flights without expending excessive energy. Enhanced understanding of how these winds shape condor movement behaviors will enable managers to better tailor the reintroduction program to the specific habitat requirements of the birds.

James Sheppard is a postdoctoral fellow for the San Diego Zoo’s Institute for Conservation Research.

Read more about his project
Read James’ previous post, Golden Eagle Helicopter Survey


Golden Eagle Helicopter Survey

During the second week of March, I participated in a helicopter survey of golden eagles and their nests along the rugged, remote, and spectacular ridges and canyons of the Sierra de Juárez Mountains in Baja California, Mexico. The survey was conducted under the auspices of Sempra Energy, which is obligated by the state government to provide a percentage of their power production through clean and renewable sources.

Sempra has obtained a lease from an ejido (cooperative farming) community to install an extensive wind farm across the northern Baja peninsula. Wind farms have great potential to reduce much of our dependency on fossil fuels by generating large amounts of electrical energy from a renewable resource with no direct byproduct pollutants. However, wind farms can also pose a considerable hazard to bird and bat populations. Wind turbines that are improperly located without regard to wildlife habitat use and movement patterns can cause high levels of injury and mortality to flying animals.

Sempra has contracted San Diego Zoo Conservation Research to conduct a full-scale survey and analysis of golden eagle population characteristics, habitat use, and movement behaviors throughout the planned wind farm site. The eagle study is part of a comprehensive assessment to avoid and mitigate the environmental impacts of the turbines. The golden eagle has high ecological and conservation management importance as a keystone species and is of particular cultural significance to Mexico as a national icon. Sempra views proper safeguarding of the golden eagle populations in the wind farm area as an essential aspect of good environmental stewardship and vital to maintaining favorable binational relations with Mexican stakeholders.

Sierra Juarez Mountains

Sierra Juárez Mountains

Golden eagles can range hundreds of miles while foraging for their food resources, such as rodents and rabbits. Eagles often use mountain ridges to ride the thermal updrafts that sweep up from the valleys and deserts below so as to gain elevation without expending much flying effort. Unfortunately, their propensity to seek out strong winds can bring the birds into proximity with wind farms. Locating golden eagles that maintain large home ranges can be very challenging. Fortunately, golden eagles can be found during the mating season in late winter/early spring as they maintain territories and incubate eggs in clifftop eyries. The remoteness and ruggedness of their habitats often precludes field-based observations of eagles from being conducted by foot or motor vehicle, so many surveys are instead done via helicopter.

An experienced team of ecologists and wildlife researchers from San Diego Zoo Conservation Research led the search for golden eagles along the mountain ridges of the proposed Sempra wind farm site in northern Baja. Team leader Dr. Lisa Nordstrom organized the survey with the assistance of Dr. Mike Wallace, Dianne Van Dien, and yours truly. Staff from the Wildlife Research Institute provided integral planning and field support, particularly executive director Dave Bittner, who has decades of experience studying raptors in the wild.

Golden eagle nest

Golden eagle nest

The survey ran for three days and consisted of broad sweeps of golden eagle habitat from a chartered helicopter. Groups of three researchers took turns taking helicopter-based observations in two-hour blocks, scanning the Baja peaks, canyons, mesas, and buttes for signs of eagles and their nests. To facilitate easier viewing, the helicopter doors were detached, which made for an extremely bracing ride as the frigid winter mountain air roared into the cockpit! After soaring across the frosted boughs of the conifer and pines of the Baja ranch that served as our field base, our pilot would fly us over the edge of the mountain escarpment. Suddenly, the earth would drop away and the aircraft would be suspended 5,000 feet over the majestic canyon system of the Sierra de Juárez Mountains. Our expert pilot hovered his craft less than 30 feet from the rock face as we buzzed up and down the sheer canyon walls at high speed, searching for eagles and their nests.

The northern section of the survey covered habitat that was mostly barren, jagged rock, but we were able to locate four nests and spot several golden eagles in the less-desolate central and southern sections. We also observed red-tailed hawks and turkey vultures, as well as three distinct herds of bighorn sheep that were grazing among the giant barrel cacti on the steep slopes.

The GPS coordinates of the nests were recorded so that researchers can travel into the area to catch wild eagles for the next phase of the project. At least six free-ranging golden eagles will be fitted with miniaturized GPS transmitters so that their movement patterns can be monitored remotely over the next two years. The data from the eagles will be analyzed to characterize their movement patterns and habitat use across seasons. Data on the movements of the California condors that are being reintroduced to the Baja peninsular by the San Diego Zoo will also be included.

This information will be used to inform planning strategies for the optimal location and operation of the wind farm and provide a predictive management tool so that the risk of harm to the birds and their habitats is minimized.

James Sheppard is a Postdoctoral Fellow for San Diego Zoo Conservation Research.

Here’s more information about James’ project

Read James’ previous blog, Are Condors Blown By the Wind?