Notes from the Field: Monitoring Mudpuppies’ Lives Under the Ice

The Detroit River in the winter can be an inhospitable place. The temperatures dip into the teens, and the wind whips large plumes of snow from the tips of frozen waves. This large and fairly fast-moving river flows south and southwest, connecting Lake St. Clair and Lake Erie. The river plays an important role as a shipping channel for freighters carrying industrial compounds and other materials used for manufacturing. 

Underneath all of this ice and hustle and bustle, one of the river’s most curious and secretive animals is carrying about its business, breathing with large, bushy external gills, foraging along the rocky bottom for food and undergoing mysterious mating behaviors. This animal is known as the northern mudpuppy (necturus maculosus maculosus), and the frozen and harsh conditions of the Detroit River are just what it’s been waiting for all summer long. 

Winter view of the Detroit River taken from Belle Isle Park.

Mudpuppies are amphibians who inhabit lakes, streams and rivers all throughout the U.S. Midwest and into parts of Canada. It is a type of fully-aquatic salamander that utilizes external gills, which are flush with blood and used to extract oxygen from its aquatic environment. Its tail is large and paddle like, and its skin is covered in a thick layer of slime. These salamanders, like all amphibians, have permeable skin and are considered to be a good indicator of environmental quality. This is one of the reasons the Detroit Zoological Society (DZS) began tracking the health and abundance of mudpuppies back in 2009.

In 2016, the Michigan Department of Natural Resources elevated the conservation status of the northern mudpuppy to a species of special concern. Since that time, the project has continued and expanded, focusing primarily on Belle Isle Park in the city of Detroit. The Detroit Zoo utilizes minnow traps to capture the mudpuppies without harming them while still collecting important data. The traps are baited with smelt and catfish bait to lure these aquatic salamanders into the minnow traps. The traps are set on the first day of the survey and pulled in on day two, so that the animals spend the least amount of time possible inside.  If a mudpuppy is found inside, DZS staff proceeds to gather data and observations about the animal, including size, weight and gender. The gills are checked for health and examined for parasites. The digits on all the limbs are checked for malformations, which could indicate the potential presence of pollutants in the river. 

Mudpuppy being weighed and examined before being released back into the Detroit river.

Once these measurements are taken, the animal is tagged with a Passive Integrated Transponder tag, which is injected into the base of the tail. This transponder can be scanned if the animal is captured again. Additionally, it tells DZS researchers useful information that can be used for future data analysis. In addition to these measurements, data is collected on water quality and additional environmental conditions, such as temperature and dissolved oxygen content. 

Based off the data so far, most mudpuppies are caught in late fall or early winter. During this time, male mudpuppies are pursuing females in the quickly cooling shallow water close to the island. Many times, staff has observed male and female mudpuppies in the same trap this time of year, most likely with the female entering the trap first before the eager male mudpuppy follows her inside. Once mudpuppies have successfully bred, the females deposit their eggs in spring, and within a month or two, the eggs hatch into several hundred baby mudpuppies!

All of this drama is taking place out on the frozen Detroit River. With ice floats and enormous boats hovering overhead, these specialized amphibians continue to live and breed intertwined in an urban environmental landscape that still holds many secrets yet to be revealed.

– Mark Vassallo is an amphibian department supervisor for the Detroit Zoological Society.

Education: Citizen Scientists Help Study Butterflies

Butterflies aren’t just beautiful animals and important pollinators; they are also bio-indicators, which provide valuable information regarding the health of an ecosystem. Like amphibians, the butterfly is affected by even the slightest changes in the environment, signaling to scientists that something is amiss. When habitats are healthy and plentiful with food, water and shelter, bio-indicator populations are stable. When any piece of that puzzle falls away, populations fluctuate quickly and may decline rapidly.

Scientists can’t be everywhere to monitor species’ populations and keep track of changes. They count on people like us to be their eyes and ears in our communities and report this critical information. The Detroit Zoological Society is providing opportunities for our community to become citizen scientists and help the Michigan Butterfly Network collect vital information about our native butterfly species.

On April 6, a citizen science training workshop will be hosted at the Belle Isle Nature Center. The training will cover species identification, how to collect accurate data, how to report data and otherwise prepare attendees to be successful.

After the mandatory training, citizen scientists are asked to visit their census route at least six times throughout the summer field season. Each census route walk will last five minutes as the observer looks for butterflies in their immediate vicinity. Recording data is a very important part of the process; each species will be carefully documented on a form and submitted to the network.

There are many support materials and resources available and the training workshops will prepare participants for a successful season. The pre-requirements include a passion for our natural world, an interest in learning to identify up to 30 species of butterflies, and the ability to visit a census route six times over the course of the summer season.

If you’d like to learn more about the project or sign up to participate in the training workshops, please email education@dzs.org.

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

Nature Play at the Belle Isle Nature Zoo

The Belle Isle Nature Zoo’s backyard is undergoing a transformation from au naturel to a natural playground area. While we believe it’s beneficial for our native flora and fauna to have natural places to grow wild and free, we also believe the same is true for local children!

What began as an ordinary space with a lot of potential is becoming an extraordinary space with a lot of possibilities for families to stay and play. While the playground environment remains filled with natural materials, the area now provides an inviting opportunity for children to exercise their imaginations, develop a sense of exploration, and enjoy some physical activity outside. Physical, mental and social health benefits flourish as a result of time spent outdoors, and we are working on designing a space that will sustain and support our guests as well as our environment.

Loose items made from natural materials inspire creative play – a balance beam from a fallen log offers a challenge of skill and concentration of gross motor skills, and a trail of tree stumps is just right for hopping, skipping, or even to be rested upon by visitors of all ages. People-sized nests are constructed and stocked with nature’s toys: sand, pebbles, stones, and “tree cookies”, which are slices of tree branches just perfect for construction play. A wooden teepee stands tall, waiting for hide-and-seekers, pretend campouts and all the creative games our small guests with big imaginations may bring.

Sensory activities are also in the works: Natural looms will build fine motor skills with a chance to use plant material to weave designs. Bamboo chimes and natural drums will inspire our natural musicians to play to the rhythm of the seasons, and colorful textural elements will reflect the beautiful palette of the natural world.

As the occasional chipmunk scampers through the playground and the birds call out their daily activities, they are at home in the natural environment (we’ve left plenty of natural “wild” spaces for our non-human animal friends around here!). Our goal with this playground is to create an opportunity for children to cultivate a sense of comfort and connection in outdoor experiences. Playing outside in nature – with nature – can help children gain respect for their environment and better understand their own place in it. And while the natural play supports the development and strength of our children, the sense of ownership they develop stands to strengthen the future stewardship of our natural world, which is vital to the health and sustainability of our planet.

We invite you to visit the Belle Isle Nature Zoo to check out our natural playground work-in-progress, hop on some logs, feel the textures and hear the sounds of nature. Tell us what you think!

– Amy Greene is a curator of education for the Detroit Zoological Society and oversees the Belle Isle Nature Zoo.

Belle Isle Nature Zoo – Little Free Library

Little Free Libraries are a global phenomenon. These small, front‐yard book exchanges number nearly 40,000 in all 50 states and around the world in 70 countries — from Iceland to Tasmania to Pakistan, and now, the Belle Isle Nature Zoo! We’ve joined the movement to share books, support literacy, bring people together and create communities of readers.

What is a Little Free Library? Little Free Libraries are hand-crafted structures filled with constantly changing collections of books donated and shared by people of all ages and backgrounds. Each year, nearly 10 million books are shared in Little Free Libraries.

Just a few weeks ago, the Belle Isle Nature Zoo chartered and then planted a Little Free Library and seeded it with books. We’ve already observed the community and literacy-building movement blossom into a fun and shared experience for our visitors. More than 100 books have already gone home with our guests from Metro Detroit and other neighborhoods around Michigan, as well as some out-of-state visitors. Additional books for children and adults have been lovingly placed upon the shelf, shared by friendly donors, and the collection is ever-changing.

We’ve been added to the Detroit Little Libraries map as well, supporting the 313 Little Libraries action plan toward making Detroit the Little Free Library capital of the world. The 313 Little Libraries action plan has a priority of planting libraries in areas with low access to books, with a special focus on places where children congregate, supported by research that shows access to books is a powerful indicator of success in school.

Not only might our guests find a great book to take home and read (and then return or share with friends) the Little Free Library provides an opportunity to give back. It allows people who want to volunteer in some way a chance to donate books and know that they are contributing to the literacy and leisure of their community.

One of the best parts about Little Free Libraries is that they don’t require library cards or late fees, don’t insist that patrons whisper or stay quiet, and don’t mind if you do not return a book.

At the Belle Isle Nature Zoo, we are known for being stewards of nature, providing experiences that build awareness toward our local ecological health and sustainability. We are pleased to also be stewards of our neighborhood literacy and building community, offering opportunities to share good things to read with one another. It’s truly everyone’s library, and the more people who participate, the better!

– Amy Greene is a curator of education for the Detroit Zoological Society and oversees the Belle Isle Nature Zoo.

Belle Isle Nature Zoo: Premier Pollinators in Action

The Belle Isle Nature Zoo is a facility operated by the Detroit Zoological Society that sits on a 5-acre site on Belle Isle surrounded by undisturbed forested wetlands. It provides year-round educational, recreational and environmental conservation opportunities for the community. The facility is free to the public, open daily in the summer, and there are a lot of wonderful opportunities to explore nature and wildlife at the Detroit Zoological Society’s campus on Belle Isle.

One of these fascinating features is the observation beehive, which provides a behind-the-scenes glimpse into the busy daily life of honeybees. Sealed tightly within a double-sided glass case, and with a tunnel providing the bees year-round access to the great outdoors, our hive invites guests to watch the bees do what they do best: work!

The work that the bees do is often more valuable than we realize. Bees are the most prolific pollinators in the natural world, due in part to their fuzzy bodies and faithfulness in buzzing to and from the same species of plant for an extended period. Pollination is the transfer of pollen from the male part of a plant or flower to the female part, which results in reproduction. In plants, one of the ways of producing offspring is by making seeds or fruit, and that surely benefits the rest of us! It has been stated that we can thank the bees for one out of every three bites of food we eat – and a lot of the good stuff, too, like fruits, vegetables, and even almonds. The pollination of bees also improves the production of the cotton plant, so not only do bees feed us, they clothe us, too!

We recently celebrated National Pollinator Week with our volunteer beekeeper, Steve Burt. He has been taking care of bees since 1974 and brings his passion for pollinators to Belle Isle. Steve maintains the health and wellness of our indoor observation beehive as well as our two outdoor beehives. With a little help from our productive honeybees, Steve bottled more than 40 pounds of delicious Belle Isle Nature Zoo honey last year!

The celebration of National Pollinator Week isn’t only for our gratitude for the fruits (and vegetables!) of the honeybees’ labor. It also helps us raise awareness to the some of the very serious challenges that honeybees are facing these days. Mites, viruses, diseases and especially certain pesticides are all contributing stressors to severe colony decline and death, often referred to as colony collapse disorder. A recent survey by the U.S. Department of Agriculture determined that beekeepers across the country lost more than 40 percent of their honeybee colonies between April 2014 and April 2015.

What can we do to help? We can plant nectar and pollen-bearing plants such as milkweed, goldenrod and aster, herbs including mint, chives, and oregano or fruits and vegetables like strawberries, cucumbers, broccoli and squash. We can encourage local governments and other volunteer groups to plant more pollinator-friendly plants in local spaces such as the areas along roadsides or within public parks. And if you have a bee problem, instead of bringing out a can of bug spray, call a beekeeper organization for species identification and useful advice.

And while you’re here at the Belle Isle Nature Zoo, you can watch our premier pollinators in action. Look for the worker bees dancing to communicate to the other bees where to find a new source of food outside. See if you can find the queen bee (identified by her larger size and a small white dot) laying eggs and being well-taken care of by her colony. You might even find some of the brood, also known as the egg, larva and pupa, or spot some stored honey in our beeswax honeycombs – a great sign that our helpful honeybees will be here for time to come!

There’s a lot of buzz about the upcoming Bee Fest event on National Honeybee Day at the Belle Isle Nature Zoo. This free event will feature demonstrations on how to build and maintain a bee-friendly garden, beekeeper talks, art, music, crafts and a bee costume parade! Buzz on over to Bee Fest on Saturday, August 20 from 10 a.m. to 5 p.m.

– Amy Greene is a curator of education for the Detroit Zoological Society and oversees the Belle Isle Nature Zoo. For more information about this facility, visit www.belleislenaturezoo.org.

Notes from the Field: Surveying Mudpuppies; Rain, Snow or Shine

We battled frigid temperatures as we entered the ice-filled water wearing insulated waders for protection against the elements.

This dramatic introduction sounds like the start of an exciting adventure story in some far-off place, but it actually describes some of the unbelievable conditions right here in Michigan where you can find one of the most fascinating creatures – the common mudpuppy (Necturus maculosus maculosus).

This four-legged, fully aquatic amphibian can be found in rivers, lakes and ponds throughout the midwestern U.S., including the waters of the Detroit River. The Detroit Zoological Society (DZS) is actively engaged in many field conservation projects, including surveying the common mudpuppy around Belle Isle. Our amphibian department has conducted surveys since 2009 as a way to learn more about the overall health and population of the salamanders found in the area. Fieldwork for the project is conducted twice monthly at two different sites, and it is never to be done alone; due to the danger posed by the elements, there must always be two people working on the survey. Depending on the weather conditions, surveys at times are limited to collecting water samples; other times it can involve trapping and processing mudpuppies.

Listed as Least Concern by the International Union of the Conservation of Nature (IUCN), little is known about the true population size of mudpuppies – not just in Michigan but also throughout its entire range. Even though this aquatic salamander has a pair of lungs, it uses blood red, feathery gills located on the sides of its head to gain oxygen from the water. It has a rather flat body and wide head and it uses its tail to move through the water. Mudpuppies prefer to hide under rocks and logs during the day and forage on aquatic insects, crayfish and fish.

Like all amphibians, mudpuppies are valuable indicators of wetland and habitat health. Since water and air move freely in and out of an amphibian’s permeable skin, they will be the first creatures to become sick or even die from the pollutants or toxins found in the habitat, warning us of any impending problems.

Fieldwork and data collection for this project is typically a two-day process. On Day 1, we are in the field collecting water samples and data on the weather, and also setting traps. To capture mudpuppies, we use small collapsible minnow traps that we weigh down to the bottom of the river and bait with frozen smelt. We tie the traps to the shoreline so they won’t be lost in the current of the river. We leave them overnight to allow the mudpuppies plenty of time in their undisturbed habitat to wander in, where they will remain until our return the following day.

The water samples we collect are taken back to our water quality lab where we can conduct more scientific tests. Keeping track of the water quality of the Detroit River is just as important as the data collected on the mudpuppies themselves. A database of this information will help us notice if severe changes have occurred in the water over time.

On Day 2, we return to the field to collect the traps as well as information on any mudpuppies captured overnight.

In the winter, the coast of Belle Isle can be quite treacherous. On one particular day in March, we faced some challenges as ice floes had moved into the shore overnight and were covering the traps we’d placed the day before. I was accompanied by two of the DZS’s most seasoned field researchers: Paul Buzzard, the director of conservation, and Marcy Sieggreen, curator of amphibians. Wearing insulated chest waders and long gauntlet-style gloves for protection against the icy waters, we did some ice stomping and managed to locate and recover all the traps we’d set.

Turned out we had captured one mudpuppy, so we proceeded to gather additional data – information from the animal, weather conditions and the water. We needed to take great care to keep the mudpuppy in the water at all times; in the winter this protects the skin and gills from freezing and in the warmer days of spring, summer and autumn it protects from the heat. We take measurements, weight and pictures of the animal, and if the salamander is healthy and large enough, a small transponder is implanted in the side of the tail to help with identification if recaptured. As quickly as possible, the mudpuppy is returned to the water in the area where we found it.

On Day 2, if conditions are favorable, we also use a digital boroscope to survey the site further. A boroscope, or a “plumber’s camera” as it’s sometimes called, is a camera at the end of a flexible 5-foot-long cable connected to a video screen. We use it to peek under rocks and logs in search of mudpuppies. This tool is a non-invasive way to learn about what else is living in the river.

As we continue with these surveys, we are exploring what other things the data we collect can show us from further analysis. We also plan to return to surveying areas off the coast off the island of Grosse Ile, which are also known to have a population of mudpuppies.

– Rebecca Johnson is the associate curator of amphibians for the Detroit Zoological Society.

Marcy Sieggreen was the curator of amphibians for the Detroit Zoological Society from 2008 until her passing in 2016. The Detroit Zoological Society established the Sieggreen Amphibian Conservation Fund in Marcy’s memory to continue to advance the work she so passionately championed.