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About Author: Ben Jurand

Posts by Ben Jurand

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Tortoises: Into the Wild

Each released desert tortoise had a radio transmitter fixed to its carapace with epoxy.

Each released desert tortoise had a radio transmitter fixed to its carapace with epoxy.

It began early in the morning, before the sun peeked over the mountains. The Desert Tortoise Conservation Center (DTCC) in Las Vegas was abuzz with activity as we prepared 32 desert tortoises for the journey of a lifetime. Little did these animals know that they were about to be brought to a new home. Many of them had been living at the DTCC for several years; some had even begun their lives as pets. Now, these tortoises would be released into the wild to try to help bolster the native populations as well as give them the chance to live their lives as wild tortoises.

When the tortoises were ready, we carried each to a preset location and placed it in a sheltered spot under a shrub.

When the tortoises were ready, we carried each to a preset location and placed it in a sheltered spot under a shrub.

After placing the tortoises in hay-lined totes, we loaded them into trucks and headed to Trout Canyon, a beautiful piece of Mojave Desert habitat over the mountains to the west of Las Vegas. Once on site, the tortoises were administered fluids to help them stay hydrated in the first weeks in their new home. We double-checked the frequencies of each tortoise’s radio transmitter to ensure we would be able to track them in the field over the coming weeks and months.

We watched the tortoises for several minutes after releasing them to see how they reacted to their new environments. As you might expect, many of them were reluctant to move for a little while, but some took to walking and started exploring their new home right away!

In the four weeks that have passed since the translocation, we’ve tracked the movements of all 32 tortoises we released, as well as 20 tortoises that were already living there. Some tortoises have stayed relatively near their release sites, exploring only about one or two football fields’ worth of the new neighborhood.

Caliche caves can act as rock burrows for tortoises, protecting them from predators and the elements.

Caliche caves can act as rock burrows for tortoises, protecting them from predators and the elements.

Shelter is a prime concern for tortoises, as they need to protect themselves from extremes of temperatures (both hot and cold) and from would-be predators like coyotes or ravens. Many of the tortoises we released have found temporary shelter under shrubs like creosote or white bursage and continue to move around in a relatively small range.

A few tortoises are taking up residence in existing burrows near their release site. The burrows may be abandoned or are occupied by accommodating neighbors. When suitable unoccupied burrows are unavailable, a few industrious tortoises have begun to dig their own.

Other tortoises have taken up shelter in caliche caves. One of the tortoises found the nearest cave to its release site and stayed there for over two weeks. Then, one day, he decided to start moving and has been walking for the past few days about a third of a mile (half a kilometer) a day.

We have tracked other tortoises traversing the landscape walking miles away from their release sites. They have covered rough terrain from windy creosote flats to rocky washes and steep mountain ridges. The end of the spring growth has provided some forage for the tortoises, and they need to take advantage and gather resources now before the heat of summer dries up the best nutrient sources.

We found a desert tortoise egg just outside a burrow.

We found a desert tortoise egg just outside a burrow.

Although the race is still on for who has traveled the farthest, one tortoise in particular has certainly moved with a purpose. She scaled steep rocky ridges and deep washes only reach the top and decide to cross the next ridge to the north. After weeks of walking, she finally took a few days off to rest. Apparently she had a mission in mind, as today we found her nesting under a blackbrush on a steep mountain ridge. She had already laid one egg; we could see it just outside the burrow!

The next few weeks will be important for the tortoises as the females continue to nest and they all settle in for the heat of summer, when they will only be active in the coolest parts of the day. Finding or building burrows in the soil or rocks is very important, as is foraging. A good rain or two would help bolster their water supply for the season, but we can only wait and see what the weather brings!

Ben Jurand is a research associate at the San Diego Zoo’s Desert Tortoise Conservation Center. Read his previous post, Time for Tortoise Training.

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Time for Tortoise Training

Ben prepares to take a blood sample from a desert tortoise.

Ben prepares to take a blood sample from a desert tortoise.

The Desert Tortoise Conservation Center (DTCC) in Las Vegas, Nevada, is gearing up for the spring translocation of a number of desert tortoises. We will be moving tortoises from the DTCC to a field location in the desert, where we will release them to help augment struggling wild populations.

Translocation is stressful on tortoises, because they need to adapt quickly to new surroundings, find shelter, and keep a lookout for both resources and predators. To give translocated tortoises the best chance of surviving in the wild, we need to make sure the animals are healthy and strong enough to be released. We also need to try to prevent them from spreading diseases to other tortoises in the wild.

As a new research associate at the DTCC, my first week included a lot of training. We were lucky to have several desert tortoise researchers and veterinarians visit from the U.S. Fish and Wildlife Service and San Diego Zoo Global to provide hands-on instruction on how to visually assess the health and condition of tortoises. We also learned how best to gather data and collect samples, including how to take oral and blood samples from the tortoises to test for diseases. We learned how to measure the size and weight of each tortoise, made notes about how their facial features and shells looked, and checked them for injuries or signs of illness.

DTCC staff take desert tortoise measurements.

DTCC staff take desert tortoise measurements.

Knowing their condition before we move them will help us track their progress over time in their new wild habitat. On some of the tortoises, we will be attaching radio transmitters to the upper part of their shell (called a carapace). After we have translocated the tortoises, we’ll be tracking their movements in the field and will monitor their health conditions in the days, weeks, and months ahead.

It is our hope that by continuing these studies, we will get a better understanding of how translocations affect the desert tortoises we move as well as their new tortoise neighbors.

Ben Jurand is a research associate at the San Diego Zoo’s Desert Tortoise Conservation Center.