Uncovering Turtle Personalities

Several years ago, we developed a project through the Detroit Zoological Society’s (DZS’s) Center for Zoo Animal Welfare to determine if we could identify specific personality traits in Blanding’s turtles. That’s right – turtles! Personality has been linked to survivorship in a number of species, and as the DZS is actively involved in conservation efforts with the Blanding’s turtle – a species of special concern in the state of Michigan – we wanted to learn more. Two personality traits emerged from our research: aggressiveness and exploration, with individuals ranging from low to high in either category. We also discovered that a connection exists between these traits and how Blanding’s turtles fare in the wild.

Researchers have been monitoring the population of Blanding’s turtles in Michigan for several years and making efforts to ensure their numbers don’t drop any further. Female Blanding’s turtles typically lay eggs this time of year, and they often travel rather long distances to find suitable nesting grounds. This certainly puts them at risk, especially as road mortality is one of the major threats they face. When baby turtles hatch, they must find their way back to water, which leaves them vulnerable to predation. The DZS became involved in a head-starting program for this species in 2011. This means that eggs are incubated at the Detroit Zoo and the hatchlings are allowed to grow up safely until they reach a certain size, at which point they are released back into the wild.

We used a series of behavioral tests to uncover specific personality traits, including what is often referred to as the mirror test. A mirror is placed in the testing space and the turtle can choose to approach it and to interact with it. As amazing as turtles are, they cannot recognize themselves in a mirror and hence perceive their reflection to be another turtle. By examining their reaction, we definitely saw each turtle as an individual. Some were reluctant to approach, some were uninterested, some were trying to interact gently, and some were very adamant that there was only room for one turtle in the pond!

Once we identified the personality traits, we wanted to understand what links there may be between personality and the turtles’ behavior and survival once released into their natural habitat. Field researchers from the University of Michigan-Flint tracked the turtles post-release for two years and shared their data with us.

Based on our analyses, turtles that demonstrated high exploration had better survival rates than those who scored low in exploration. During the first year, turtles that were more aggressive traveled further from their release site, but over the entire course of the tracking period, turtles that were more exploratory traveled the most. Turtles that were rated as more aggressive and exploratory were found basking more often. Turtles will rest in the sun to help thermoregulate. This helps them to be more energetically efficient, but being exposed may put them at higher risk of predation. The different personalities therefore behave in different ways that amount to a trade-off in risks and benefits.

Finally, all turtles, regardless of personality, showed a distinct preference for areas vegetated with cattails. Given this demonstrated preference, we now know that this type of habitat might really benefit turtles in future releases.

– Stephanie Allard, Ph.D., is the director of animal welfare for the Detroit Zoological Society and oversees the Center for Zoo Animal Welfare.

Notes from the Field – Wolf/Moose Research Continues on Isle Royale

The Detroit Zoological Society’s (DZS’s) ongoing involvement in the important conservation project Wolves & Moose of Isle Royale – the longest continuous study of any predator-prey system in the world – continued with a recent expedition to this remote island.

 

Isle Royale is located in the frigid waters of Lake Superior. At more than 40 miles long, it is the largest island in the largest of the Great Lakes. This national park is also home to a population of wolves and moose – moose first came in the early 1900s and wolves joined in the 1940s after crossing an “ice bridge” from Canada. For more than five decades, researchers have studied the lives of these animals and their fluctuating populations in order to better understand the ecology of predation and in turn, gain a better sense of our relationship with nature.

 

I recently traveled to Isle Royale with David Anthony, a DZS education specialist, to conduct research for this project. We took the ferry from Grand Portage, Minnesota to the Windigo Ranger Station on the southwest end of the island – the opposite side from where we conducted fieldwork in 2016.

 

Because ice bridges form more rarely between Isle Royale and Canada due to the changing climate, the wolf population at this location has dropped to only two closely related individuals. The Wolf-Moose Project currently focuses on how the moose population is responding to reduced wolf predation and how the forest is responding to the increased moose population. While there is a proposal to reintroduce more wolves, it is a complicated issue in part because Isle Royale is also a national park. The National Park Service is expected to decide on this proposal this fall.

 

Once we arrived at Windigo, we donned our heavy backpacks in a light rain for a 5-mile hike to our first camp, which was situated next to a large beaver pond. It was a cold, rainy night and rather unpleasant, but it was a relief that the next day was sunny and we were able to dry out our clothes and equipment.

We hiked 2-3 miles each day, carefully looking for moose bones in the dense forest, traveling up and down ridges and through swamps. On our first full day in the field, we located a nearly complete skeleton with an antlered skull. The skulls and teeth were an especially successful find, because when cut into a cross section, the rings of dentin in the teeth can be counted to age the moose – similar to counting tree rings – which provides important information on the moose population. The bones are also examined for signs of chewing by wolves as well as signs of arthritis – many moose at Isle Royale live longer and are more prone to developing arthritis than moose in areas with more predators.

 With this information, we then try to surmise the cause and time of death to learn more about when wolves were still predating or scavenging moose. Our team also documented the harmful effects moose are having on Isle Royale’s fir trees. Moose rely on the relatively soft fir tree needles for food during the winter, and in many areas, they have continually browsed the tops of fir trees so they stay short and cannot reproduce. With taller, reproducing fir trees becoming scarce on the island, the over-browsing of the short fir trees is a serious concern.

 

After several days, we hiked to our next camp on the shore of a sheltered harbor on Lake Superior. This site was situated next to an active beaver lodge that kept us up at night with tail slapping and the “kerplunk” of beavers diving under water. On our next trek, we found another, even larger antlered skull, and there was more clear evidence of wolf predation – or at least scavenging – with chewed-up leg bones found dragged away to shady trees nearby.

As we wrapped up our journey, we connected with another group of researchers exploring a different part of the island; both teams returned with moose bones and teeth for examination, marking a very successful field expedition.

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– Paul Buzzard, Ph.D., is the field conservation officer for the Detroit Zoological Society.

Help us Protect a Billion Birds from Untimely Deaths

Every year, thousands of avid birders flock to important birding areas in the state of Michigan, hoping to see or hear a few of the millions of birds that are migrating to their breeding grounds. Birds migrate north to their breeding grounds mid-March through May; they then migrate south to their wintering grounds mid-August through October. Unfortunately, many migratory birds will meet an untimely death by colliding with glass or manmade structures, a phenomenon known as a bird collision or bird strike. It has been estimated that up to 1 billion bird-collision deaths occur every year in the U.S., according to the American Bird Conservancy. As humans continue to build structures that contain glass, the threat of bird collisions will also continue.

Birds and humans have a different visual system – we see the world differently. Glass appears invisible to birds and becomes a dangerous barrier they are unable to avoid. Oftentimes as a result, birds will fly directly into windows, causing fatal injuries. In some cases, a bird will fly away after a collision, but it will likely succumb to its injuries elsewhere.

The good news is that there are many things we can do to prevent these collisions from happening. Windows with blinds on them can be made safer to birds by keeping them partially or fully closed. Moving plants away from windows without blinds can prevent birds from thinking they can land on them. Moving bird feeders to within 3 feet of windows or more than 30 feet away from windows can prevent these collisions. There are also a variety of window films that reduce reflection on the outside of windows: ABC BirdTape can be hung vertically – 4 inches apart, or horizontally – 2 inches apart. One of the most common preventative measures people use is decals. Decals come in many shapes and forms but the most common type used is a bird silhouette decal. Companies and homeowners can also build bird-friendly buildings by incorporating reduced visibility of glass, incorporating designs in/on glass and minimizing the use of glass.

 

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The Detroit Zoological Society believes it’s important to take care of all birds, not just those that live at the Detroit Zoo. The DZS has been committed to tracking and preventing bird collisions on Zoo grounds since 2013. All newly hired employees are required to attend orientation and learn how to recognize and report bird collisions to their supervisors. Bird department personnel have used a variety of measures including ABC BirdTape, custom CollidEscape window film and bird decals to prevent collisions. The Polk Penguin Conservation Center has specially designed “fritted” glass, and we recently incorporated custom ORNILUX Bird Protection Glass into the renovated giraffe building – this glass contains a patterned UV coating, making it visible to birds but transparent to the human eye. Detroit Zoo visitors have access to educational flyers and displays about bird collisions at various locations throughout the Zoo and ABC BirdTape is available for purchase at the Zoofari Market.

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We encourage the community to take preventative measures to protect wild birds from colliding with windows in their homes, schools and businesses. Residents and property managers of high-rise buildings, apartments and condominiums can participate in the Detroit Audubon’s Project Safe Passage Great Lakes by turning off all building lights at night on unoccupied floors and spaces. Lights left on in buildings overnight are a major cause of nighttime collisions that kill millions of birds.

– Bonnie Van Dam is the associate curator of birds for the Detroit Zoological Society.

Porous Pavement Protects Sewer Systems

Observe storm water disappear right before your eyes through the environmentally beneficial phenomenon known as permeable pavement. Constructed of porous materials, it allows for the passage and filtration of water. While “normal” asphalt and concrete tend to be a less expensive option, permeable pavement has many benefits that help our environment, making it a better – and greener – alternative. During heavy rainfall, sewer systems tend to get overwhelmed and may result in flooding, along with basement backups and polluted waste water. To combat this, the porous material captures the runoff and filters out any pollutants. This collection of rainwater also helps to recharge groundwater and reduce surface temperatures, which is extremely beneficial to the surrounding ecosystems.

The Detroit Zoological Society (DZS) is paving the way for a more sustainable environment by utilizing this progressive green design. We first implemented permeable pavement at the Detroit Zoo in 2015 with the construction of the Cotton Family Wolf Wilderness, which features visitor walkways made with porous material. As we continue to improve the infrastructure at the Zoo, we are incorporating permeable pavement within our design plans, such as a parking lot we constructed in 2016 near the main entrance with 215 additional spaces, as well as a new visitor walkway outside the Edward Mardigian Sr. River Otter Habitat added in 2017.

Join us on our Green Journey! By implementing sustainable storm water infrastructures, we can help relieve the influx of water into the sewer system. Try disconnecting your downspouts and channel the water into your lawn or garden, plant a rain garden with native Michigan flowers and/or harvest rain water – these are all cost-effective ways you can help too.

– Rachel Handbury is the manager of sustainability for the Detroit Zoological Society.