Notes from the Field: Saving Tree Frogs in Honduras – Part II

As part of the Detroit Zoological Society’s (DZS’s) continuing efforts to save amphibians from extinction, we recently introduced readers of the DZS Blog to three species of endangered frogs that live in the Cusuco National Park in Honduras. These species are at high risk of extinction and we aim to help their populations. If you haven’t had a chance to read my previous blog entry, click here.

Amphibians are facing an extinction crisis, and one of the most tangible causes is disease. In my previous entry, I mentioned the chytrid fungus and how it is causing amphibian deaths globally. Many theories exist as to where chytrid originated and how it spread, but regardless of the answer to those questions, the fungus has now been found in almost every environment all over the world. Removing the fungus from the environment does not seem to be a possibility since it has become so widespread, as this could potentially damage the ecosystem and other lifeforms in it. So, the question becomes: How do we save the frogs?

Frogs are most susceptible to chytrid when they are young – tadpoles and juveniles have the highest death tolls as a result of this fungus. The tadpoles of the three target species we are focusing on in Honduras (the exquisite spike thumb frog, the Cusuco spike thumb frog, and the mossy red-eyed tree frog) are especially sensitive to chytrid. The tadpoles have very strong mouths, which they need to be able to use as a “suction” to hold onto rocks in rapid waters of rivers. Doing so is vital to their survival, and as such, chytrid is particularly damaging to these animals. Chytrid is attracted to keratinized skin cells, which are found in the mouths of tadpoles. The resulting infection causes them to lose function of their mouths, which can cause them to have trouble eating and difficulty with “suction” onto rocks. The loss of this suction can cause tadpoles to be swept downstream into unsafe waters.

Photo by Jon Kolby

This is all devastating; however, we came up with an idea for how we might be able to help.

What if we could remove tadpoles from the stresses of the environment during the stage in which they are most sensitive to chytrid? Using our skills and expertise in caring for amphibians, we might be able to nurture them in a pristine environment. The lack of stress would potentially prevent symptoms of the fungus from appearing. Alternatively, if symptoms did arise, caretakers could treat the fungus to assure survival. Then, when the animals have reached adulthood, they could be returned to the wild.

This method of rearing animals through sensitive stages is called “head-starting”, and is a method frequently used with amphibians. It has shown to be beneficial in instances just like this, where adults survive better than offspring. Long term, the hope is that the increased population from the head-started animals would be enough to booster the population into stability.

Photo by Jon Kolby

The Detroit Zoological Society and the Honduras Amphibian Rescue and Conservation Center are ready to start head-starting animals. Facilities have been built in Honduras in order to provide tadpoles a safe place to live and grow until they are ready for release. In an upcoming entry on the DZS Blog, we will go inside the rescue center’s facilities and show you what the tadpole rearing experience will look like!

– Dr. Ruth Marcec is the director of amphibians for the Detroit Zoological Society and oversees the National Amphibian Conservation Center at the Detroit Zoo.

Notes from the Field: Saving Tree Frogs in Honduras – Part I

The Detroit Zoological Society is collaborating with the Honduras Amphibian Rescue and Conservation Center to preserve three species of endangered frogs from the cloud forests of the Cusuco National Park in Honduras. The rescue center is an in-country facility that aims to re-populate these three endangered species through programs such as head starting, captive breeding, habitat protection and community outreach.

Amphibians all over the world are suffering extinctions, and the species in the Cusuco National Park are at a particularly high risk. There is a fungal disease, called chytrid, that is causing drastic population declines amphibians globally. Chytrid fungus has been particularly devastating to amphibians that live at higher elevations in the tropics, because the fungus thrives in lower temperatures and high humidity. This fungus likes to live in keratinized skin cells, and because amphibians rely on their skin to breath and exchange nutrients, it can be very deadly. The Cusuco National Park is a protected area that is home to many rare amphibian species who, unfortunately, are subjected to this fungal disease. The Detroit Zoological Society is working with the rescue center to investigate how to help save these animals from extinction.

While there are many species of amphibians in Honduras that need help, we decided to start our mission with three “target species” of critically endangered tree frogs. Once we find the best way to help these species, we can apply what we learned to others locally. These three target species are the exquisite spike thumbed frog (Plectrohyla exquisita), the Cusuco spike thumbed frog (Plectrohyla dasypus), and the mossy red eyed frog (Duellmanohyla soralia). All three of these frogs have been found to have the highest infection rates with chytrid fungus in the Cusuco National Park and are at high risk of extinction. This spring, we conducted fieldwork in Honduras, visiting the natural habitat of the three target species to help gain a better understanding of their behavior. We were able to observe some never-before-seen behaviors of these interesting animals that will help us increase our chances of protecting them.

Before I get too carried away, let me introduce you to the three species!

Photo by Jon Kolby

Exquisite spike thumb frogs are the largest tree frog in the Cusuco National Park at approximately 4 inches long. These frogs are found exclusively in the small protected area of the park, and are listed as Critically Endangered by IUCN. The frogs get their name from the large boney projection that males have on the sides of their thumbs, called a prepollex. It is theorized this special appendage is used for male combat, but combat has not yet been observed in this species. Additionally, the call of these frogs has never been heard (or at least recognized) by human ears.

Photo by Jon Kolby

Cusuco spike thumb frogs also only live in the small protected region of the Cusuco National Park; they are also listed as Critically Endangered. This species also gets its name from a prepollex in the males. Cusuco spike thumb frogs are medium-sized, growing to about 2 inches. Their call is a “quack” noise, similar to a duck. When threatened, these frogs have been observed jumping into leaf litter and burying themselves, which is unusual behavior for tree frogs.

Photo by Jon Kolby

Mossy red-eyed tree frogs are the smallest of the three target species, at a maximum of about 1.5 inches, and are also listed as Critically Endangered. As tadpoles, they have a striking green sheen to them, and they perform an odd behavior. They will flip over on their backs to swim – bellies up – in the rapids of waterfalls. Mossy red-eyed tree frogs can be heard calling with a series of chirps and clicks.

The Detroit Zoological Society and the Honduras Amphibian Rescue and Conservation Center have a plan to save these amazing animals. I’ll be sharing more details about this plan in upcoming blog entries, so stay tuned!

– Dr. Ruth Marcec is the director of amphibians for the Detroit Zoological Society and oversees the National Amphibian Conservation Center at the Detroit Zoo.

Wildlife Conservation: Breeding Eastern Tiger Salamanders

Amphibian breeding season is here! That means it’s time to start helping amphibians get in the mood for love and romance.

The Institution of Museum and Library Sciences (IMLS) recently awarded a $500,000 National Leadership Grant for the purpose of improving reproduction within captive assurance colonies of imperiled salamanders. The Detroit Zoological Society is one of the primary partners on this grant. My doctoral research focused on salamanders, their reproductive physiology and techniques to help them breed, and that very research was the basis for the recent IMLS grant proposal.

Other partners on the grant include Mississippi State University and Omaha’s Henry Doorly Zoo and Aquarium. Now that the grant was awarded, techniques must be taught to the other partners so we can all work together in salamander conservation efforts. I recently visited Mississippi State University in order to train the other principal investigators and the graduate students involved on this salamander grant in principles of natural salamander reproduction and performing assisted reproduction techniques with salamanders.

The training session involved eastern tiger salamanders (Ambystoma tigrinum), which are regionally threatened and endangered in various areas of North America. Like many species of salamanders, the tiger salamander is very difficult to breed in human care. Similar to other species in the “mole salamander” family, tiger salamanders respond to changes in air pressure and temperature when seasonal rain storms occur. These storms are what cue breeding behavior and are very difficult to replicate in human care. Without the ability to provide the appropriate “mood”, tiger salamanders in human care will not often feel romantically inclined. Natural breeding is always the first goal when breeding animals for conservation, but sometimes this is extremely challenging. In these cases, we use alternative techniques while we perfect replicating the natural breeding environment.

In vitro fertilization is a technique used to assist salamanders and other amphibians in breeding. Most salamander species undergo internal fertilization, in which the female picks up a capsule of male sperm, called a spermatophore, which the male has deposited into the environment. The female holds the sperm in an internal pouch that she later empties over her eggs as the eggs are laid. In in vitro fertilization of salamanders, sperm is collected from males by giving them a massage. Eggs are then collected from the female into a small dish where sperm is placed on top of the eggs. Just add water, and presto, you have salamander babies. Of course, it is never just that easy, but the concept is straightforward.

I trained the other primary investigators and students in other techniques as well, including cryopreservation – or freezing and long-term storage – of salamander sperm and sperm quality assessment. The training was very successful, with nearly 100 tiger salamander babies produced. Now the trainees can go on to teach more amphibian conservationists, and we can save more species by assisting with breeding!

– Dr. Ruth Marcec is the director of the National Amphibian Conservation Center at the Detroit Zoo.

Animal Welfare: A Compassionate Approach to Toad Conservation

Staff members from the Detroit Zoological Society’s (DZS) National Amphibian Conservation Center and Center for Zoo and Aquarium Animal Welfare and Ethics are collaborating to find out what toads like. By doing so, we can ensure we are providing for their welfare while they’re in our care and also contributing to the conservation of this species in the wild.

Wyoming toads (Anaxyrus baxteri), also known as Baxter’s toads, are considered extinct in the wild, and their numbers must be bolstered each year by reintroductions of individuals born and reared in the care of humans. They can be found in two locations within the Laramie Basin in Wyoming, thanks to efforts by the U.S. Fish and Wildlife Service and other dedicated organizations including the Detroit Zoological Society.

Wyoming toads were abundant until the 1970s when their numbers began to plummet due to the spraying of aerial pesticides, habitat alteration and the fungal infection caused by chytridiomycosis, which is decimating amphibian populations worldwide. By 1984, the species was listed as endangered and in 1993, that listing changed to extinct in the wild. That year, what were believed to be the last 10 remaining Wyoming toads were brought into a facility to safeguard them and begin a breeding program in the hopes of one day reestablishing the species in the wild.

The Association of Zoos & Aquariums started an official Species Survival Plan for the Wyoming toad in 1996, a program in which the DZS has been very active, including releasing thousands of toads hatched at the Detroit Zoo since 2001. Through the efforts of this collaborative breeding program, more than 1,500 Wyoming toads are currently believed to live in the wild.

Because breeding success continues to be a great concern for this species, the Wyoming Toad Species Survival Plan established strict guidelines for habitat setup at the participating institutions. The habitats are rather sterile to reduce the potential development of any disease processes and consist of a dry area typically made of PVC, a water feature, a basking lamp and a shelter. This type of setup was necessary to properly monitor conditions to promote higher survival rate and breeding success. Due to the success of the reintroduction program, new habitat parameters can be explored, providing the toads with a more stimulating environment.

It is important that we assess how this affects the toads and what preferences they might have. To that end, habitats are being created that provide the toads with a choice between the standard habitat and one that has more naturalistic elements, such as soft substrates, multiple shelters and water features of varying shapes and sizes. With the assistance of our current resident, Emilie Gupta, we will be studying the toads to determine if this choice is important to them. Providing animals with choices and agency – or control – over certain aspects of their lives has been proven to positively affect welfare in some animals. This research will augment what we know about amphibian well-being and will add a compassionate dimension to this conservation success story, in which ensuring the welfare of individuals is a critical part of protecting the species.

Dr. Stephanie Allard is the director of animal welfare for the Detroit Zoological Society and oversees the Center for Zoo and Aquarium Animal Welfare and Ethics.

Education: Community and Conservation

Four teenaged girls recently assisted the Detroit Zoological Society (DZS) with our amphibian conservation efforts by pairing up with staff members to build mudpuppy shelters at the Detroit Zoo’s Ford Education Center. These young ladies were from Oakland County’s Children’s Village, a residential treatment and detention center for youth. The DZS began a partnership with Children’s Village in 2009 to instill respect and reverence for wildlife and wild places within the hearts of these teenagers. The program expanded in 2016 to offer off-site community service opportunities for the residents.

Mudpuppy shelters are an important piece of our ongoing conservation work as we monitor the population of these aquatic amphibians on the shorelines of the Detroit River and the inland lakes of Belle Isle. Mudpuppies are indicators of water quality; they cannot survive in polluted or contaminated water, so their presence is a sign of a healthy aquatic ecosystem.

DZS amphibian staff provided the specifications for the height, width and depth of these cement structures, as well as the materials to make them. The young ladies worked in pairs with DZS staff members, donning thick gloves and using wire cutters to trim heavy-duty wire mesh, before folding and binding it to form the bottom of the shelter. They then layered the cement over the wire mesh and built it into a solid, smooth floor and walls. Separate pieces of wire mesh were then cut to size and layered with the cement mixture to create roofs for the shelter.

Once the weather warms up, the shelters will be placed in the water around Belle Isle in hopes that mudpuppies will find them a desirable place to lay their eggs. They tend to lay their eggs under rocks in their natural habitat, which makes it difficult for researchers to locate the eggs without potentially disturbing them by having to move rocks. With the easy-to-remove roof on these homemade shelters, mudpuppies could lay their eggs inside and DZS staff would be able to lift the top and easily check on the eggs without disturbing them.

The young ladies who helped build the shelters will join us down on Belle Isle in the coming weeks to place them in the water. They will have the opportunity to work alongside DZS amphibian and education staff to record weather, water quality and shelter placement as well as check on previously placed shelters.

These teens are facing many challenges in their lives and working alongside scientists in the field offers them the chance to explore careers they may not have otherwise known about or considered. It is an opportunity for them to try a new experience, build skills and understanding, and give back to the community through conservation.

Claire Lannoye-Hall is a curator of education for the Detroit Zoological Society.

Notes from the Field: Saving Seabirds in the Falkland Islands

On a recent conservation expedition to the Falkland Islands – the Detroit Zoological Society’s (DZS’s) second in two years – I met with the governor of the islands and commissioner of the nearby South Georgia and South Sandwich islands, His Excellency Nigel Phillips CBE. We discussed the need and potential for penguin conservation work in the region, and the important role that the DZS can provide. Through our partnership with organizations such as Falklands Conservation (FC), which is working to conserve rockhopper, gentoo and king penguins – three species of penguins living in the Detroit Zoo’s Polk Penguin Conservation Center – and other seabirds, we can not only provide financial support but also scientific expertise in the field. Additionally, we teach, engage and inspire millions of Detroit Zoo visitors about these incredible animals, their plight in the wild, and what people can do to help.

The Falkland Islands, located off the southern tip of South America, provide critical habitats for several species of penguins and other wildlife. However, threats are looming from oil extraction and increasing ecotourism, and it is essential to establish marine protected areas and assess the impacts ecotourism brings. On our recent expedition with Falklands Conservation, we set out to monitor the population of penguins and other seabirds living on several islands off the easternmost coast of the Falklands – some which had never been visited and others that had not been visited for more than 10 years. The islands were close to the military port near Stanley, the capital of the Falklands, but rather remote, and landing on some of them was quite difficult because of the sea swells and cliff faces. In fact, we weren’t able to land at all on one of the islands called The Mot, and instead used a drone to effectively document the birds’ habitat.

We made some important observations on these excursions. As the sun went down during our drone visit to The Mot, we noted the return of hundreds of sooty shearwater birds returning to their burrows. Shearwaters are a threatened pelagic sea bird and an important indicator of well-managed fisheries, so documenting the location of a new colony was significant. We also documented the first records of Cobb’s wren on another island, which are ground nesting birds endemic to the Falkland Islands and important indicators that the land is free of rats and mice. These rodents have been introduced to many of the islands and have devastated populations of Cobb’s wren and other ground nesting birds. Additionally, we were heartened to see that the habitat at another island, Motley, has recovered tremendously from earlier sheep grazing. The plant life on this island was diverse with rare flowers such as yellow orchids and hairy daisies. Gentoo penguins were also observed at Motley, so it is possible and promising that a previously observed gentoo colony nearby is expanding.

The DZS hopes to establish a long-term project site at the Falklands to analyze the impact of ecotourism on penguin breeding, health and welfare. Tom Schneider, the DZS’s curator of birds, and I investigated several potential sites that have king and/or gentoo penguin colonies. We also had the opportunity to visit the Seabird Rehabilitation Facility, which was designed to accommodate small-scale wildlife rescue efforts, often involving oiled penguins. With increased oil development on the horizon, the number of oiled birds needing proper cleaning and rehabilitation is sure to increase. The DZS has produced educational panels that will be displayed at the facility which detail its history, the impact of oil pollution on seabirds, the extensive process that goes into caring for oiled birds, and several success stories of birds who have recovered and been returned to the wild.

– Paul Buzzard, Ph.D., is the field conservation officer for the Detroit Zoological Society, which leads and supports wildlife conservation work on six continents.

Notes from the Field: Tiny Shorebirds Get New Chance at Survival

The piping plover (Charadrius melodus) is a small shore bird that breeds in three distinct geographic locations; the beaches along the Atlantic coast, the shorelines of the Great Lakes, and along major rivers of the northern Great Plains. The Great Lakes population is classified as endangered by the U.S. Fish and Wildlife Service; the other two populations are classified as threatened.

At one point, this population of Great Lakes piping plovers was estimated to range from 12 to 32 breeding pairs. After extensive observation, scientists found that plover nests were abandoned and concluded that salvaging these abandoned eggs could contribute to the species’ recovery. For almost two decades, the Detroit Zoological Society (DZS) has led the effort to collect these abandoned eggs, incubate them and rear the chicks that hatch until they can be released to join wild plovers.

The DZS operates the captive rearing facility at the University of Michigan Biological Station in Pellston, Mich., and oversees aviculturists from the Detroit Zoo and other Association of Zoos & Aquariums institutions who staff the facility from May through August. The dedicated zookeepers monitor the eggs during incubation and care for the chicks after they hatch. Once they are able to fly, after about four weeks, the birds – that would have otherwise perished – are banded and released into the wild. As they migrate to their wintering grounds, the plovers are identified by birders and photographers who report their findings to the U.S. Fish and Wildlife Service.

I spent five weeks this summer at the captive rearing center, working with what I believe are some of the cutest chicks in the world. While our conservation efforts have been incredibly successful over the last 17 years, the Great Lakes piping plover population is still less than 80 breeding pairs annually. This year, seven DZS zookeepers and 12 staff members from eight other zoos helped raise 16 chicks from abandoned eggs to join the more than 90 chicks that wild birds raised.

Adult piping plovers tend to breed around the shores of the Great Lakes on large patches of undisturbed sandy beach filled with cobble. Sometimes, their nests are washed out by waves, a parent is killed by a predator, or an unleashed dog causes abandonment. These nests are closely monitored and when staff has determined that the eggs are not being incubated, they are officially declared abandoned and the eggs are transferred to the captive rearing center. In some cases, such as when a storm is passing through, “dummy” eggs will be placed in the nest while the real eggs are placed in an incubator overnight and then returned the next day.

The captive rearing center has multiple incubators and equipment to nurture each egg and provide the conditions it needs to develop a healthy embryo. After almost four weeks in the egg, a little plover chick will spend two to four days hatching. Newly hatched chicks weigh about as much as three pennies yet are very mobile, looking for food within a few hours of hatching. When a full clutch of four chicks hatches, it looks like four cotton balls on eight toothpicks running around.

Rearing plover chicks properly and assuring they will be ready for release is no easy task. We weigh the chicks every morning and observe them to make sure each bird is thriving. Bonnie Van Dam, the DZS’s associate curator of birds and manager of the captive rearing operations, fields any questions from staff. One chick in particular needed a little more help from staff this year as it had difficulty hatching, curved toes, bowed legs and some feather abnormalities (genetic issues that can’t be avoided), but zookeepers did not give up on this little chick, providing antibiotics, extra feeds and extra practice flying. In the end, although a little different, this bird had incredible character running around and flying well.

We routinely feed the birds a variety of insects every few hours while they also learn to forage on wild insects. They grow fast and their flight feathers start coming in within two weeks. At 17 or 18 days old, the piping plovers are starting to stretch their wings and by 25-27 days they should be flying well. We have one flight pen along the beach where the plovers grow, forage and learn natural behaviors; another is attached to our building to give them outdoor access overnight and more space to practice flying.

Plover fledglings are usually released between 28 and 33 days old. This year we reared 16 chicks that were released into the wild. Most releases occur in an area where there are similarly aged wild chicks; often the releases happen at Sleeping Bear Dunes. It is an incredible feeling opening the door to the crate and letting these small chicks fly free. They immediately start foraging, bathing and or flying around. With a little luck and some decent wind, they will make it to the Atlantic coast or maybe even the Bahamas, enjoy winter, and return to northern Michigan next spring. On August 14, we released the final four birds of the season at Sleeping Bear Dunes, including the special little chick who needed all the extra help. This bird ran down the beach and almost immediately started flying! Each piping plover is a special part of our Great Lakes ecosystem – please be mindful as you share the beaches with these charismatic yet fragile friends.

– Matthew Porter is a bird department zookeeper for the Detroit Zoological Society.