American Beaver

Text and Photos by Linda Hagan, Maryland Master Naturalist

I had the opportunity to go to a program about beavers sponsored by the Natural History Society of Maryland. The program was held at Boordys Vineyards where they had been having problems with flooding of a roadway caused by beavers. Rather than have them trapped and removed, they wanted to find a way to co-exist with the beavers, so they contacted a local conservation company which specializes in beaver restoration projects. The presentation covered management practices which could be used to save the beavers and allow them to do what beavers do best, make and restore wetlands.

Beavers are considered a “keystone” species. The dictionary definition: a species upon which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically. One great example of a keystone species was when wolves were reintroduced to Yellowstone National Park. There has been much written about the remarkable change wolves made in a very positive way to the habitat. So much so that other creatures who were no longer there came back. If you can, I would advise everyone who cares about ecosystems and the diverse animals that exist in them to read about the wolves of Yellowstone. Today, however, I am going to write about a creature who lives in Frederick and surrounding counties. This keystone species is the American Beaver.

Beavers are the largest rodent in North America and second largest in the world. They can weigh from 30-60 lbs and can be 40” in length which includes their tail. Beavers were almost hunted to extinction in the mid-1800’s for their valuable thick fur which was used to make top hats. I’m happy to say that beavers have been aided by wildlife management practices and, with their prolific breeding have made a comeback and are hopefully now here to stay. The importance they plan in wetland creation can not be understated.

Beavers can live near humans, but because they are shy they prefer more isolated locations which are unfortunately getting harder to find. Beavers live near streams, creeks, ponds, marshes and small lakes where there is constant water sources; they prefer them to be narrow enough for easy damming. They build dams made of tree cuttings which they pack together with mud and rocks. Beavers cut down trees within 200 feet of the water’s edge so they don’t have to drag the wood very far. Staying close to where their dam and lodges are also helps them avoid predators. Beavers sometimes dig canals from the pond to land so they can float the logs back to the dam. One beaver can cut down between 216 and 300 trees with diameters of 3” or less in a year. On average one acre of aspen trees can support a 5-6 member colony of beavers for 1 to 2.5 years. Beavers are monogamous and have one mate usually for life. They have a single litter of between two to five kits which are born between May and early July. They weigh 1 pound and are a foot long. Kits are fully furred, and their eyes and ears are open. They can swim within hours of being born, but are too buoyant to submerge themselves for several days and the fur is not yet water repellent. At 3-4 weeks old the anal glands used to oil the fur are functioning and they can waterproof their fur. Beavers are also social animals and their colony consist of a breeding pair and two generations of offspring which stay with their parents until 2 yrs of age at which time they are driven off to find their own territory.

They build dams to backup water around the domed shaped lodge they live in so they are protected from predators. These lodges are made of sticks and logs which is plastered together with mud. The lodge can be up to 5’ high and consist of a feeding den, a resting den, and a small air hole at the top for fresh air. When the mud of these lodges freezes it is almost impossible for a predator to break through, but if they succeed the beaver has two underwater entrances they can use to escape. The entrance to the lodge is always below water level. The beaver dams can hold back a great deal of water, but it also allows the water to continue to flow through it. Beavers are constantly maintaining the dams and can heighten the water level by making the damn higher. They need a water height of 2’-3’ to feel safe.

Beavers are herbivores. During the spring and summer they eat aquatic plants such as tubers from cattails and water lilies and shoots from young plants. Beavers cut down trees to get the newer, more succulent growth. During the winter they eat woody vegetation like bark and twigs from birch, ash, willows, poplar, aspen, cottonwoods, pines and other species of trees.

During the fall months beaver have three important jobs they must perform before winter. They refurbish their lodge, they repair and strengthen the dam and they must cut and store food for the winter months. They cut branches, twigs and small logs which they anchor in the mud at the bottom of the pond. This allows them to have a food supply when the pond freezes over. If the ice is thin the beavers can break it from underneath by bumping it with their heads which creates a crack. The beaver then pokes its head through the hole, lifts its front feet up onto the edge of the ice and lunges forward breaking a path with its body and continues to do this until it gets to its destination. If the water level of the dam is too high the beavers will raise the floor of their lodge and the roof of the sleeping chamber.

Beavers must continue to cut wood because, like other rodents, their teeth never stop growing. The eyesight of beavers is weak, but they have a good sense of smell and hearing. They can stay underwater for up to 15 minutes and have a membrane that seals the ears and nose while underwater. They also have transparent eyelids that help them see underwater. The tail which is trowel shaped, has scaly, leathery covering and is 8”-12” long and about 6” wide. The beaver uses its tail as a propeller and rudder. It will also smack its tail on the water as a warning of danger to other beavers. They have long claws on heir feet for digging and the hind feet are webbed to help them propel through the water.

Beavers have a thick winter coat, a water proofing oil and thick layer of fat. At 32 degrees a beaver’s resistance to heat loss in water is about 1/8 of that in air at the same temperature. The fur is compressed in the water which allows the insulating air between the hairs to escape. Beavers also retain heat through their tails and hind legs which serve as heat exchangers. The beaver will only loose 2 percent of its body heat through its tail in winter, but 25 percent of it in the summer. They must constantly groom their fur to keep it clean and oiled to keep it waterproof. Without the oil the fur would become water soaked.

Both sexes have a musk sac that makes an oily substance called “castoreum.” Beavers use a mixture of urine and castoreum to mark their territory on “scent mounds”. They do this by piling up mud and leaves from the pond into a mound. They than deposit the castoreum by straddling the mound and everting the castor sacs and dragging them across the mound. These mounds can vary in size from a few inches to three feet. This scent mound conveys information about the beavers age and sex. The purpose is to communicate to other male beavers to continue on their way. Castoreum is used for communication and oil from the anal glands is used for water proofing their fur. Castoreum has also been used commercially in perfumes and medicines.

As a keystone species, beavers play a very important role in creating wetland habitat. They build a dam in a wooded portion of an area and as the water covers the tree bases, the trees will eventually die. These dead trees called “snags” will become homes for cavity-nesting birds such as woodpeckers, owls, ducks and others. These “snags” are vital nesting sites. It also creates habitat for shorebirds, ducks, fish, reptiles and amphibians. This rich diversity of life will than attract predators like otters, minks, raccoon, hawks, owls and others to the area. When after many years the wood supply they need is gone the beaver will move on to find a new territory. Once they have left and they are no longer there to maintain the dam, it will eventually break and the water will run off creating an open area where grass, shrubs and berry bushes will grow that attract insects and rodents. This new habitat will now attract insect eating birds such as songbirds, plus deer, bear, turkeys and herons. The flow of the natural world continues as a different habitat emerges and has been created. All of this is due to the American beaver.

Beavers were once hunted and trapped to the point of extinction and thought of as only rodents who caused trouble with their dams because they flood roads, pastures and crops. However we now know we can manage their dams with devices such as the flow devices like one installed at Boordys. Humans can actually benefit by letting beavers help us with wetland restoration projects. They can reduce costs because the beavers do the work for free. People are now coming from around the world to attend Beaver Conferences where they learn how beaver can be used to restore wetlands and river restorations. Using funding from NOAA, salmon habitat is being restored in Bridge Creek Oregon. Beavers are industrious creatures whose dams trap sediments, increase flood plains and create wetlands for wildlife. We have learned so much by studying them. No more are they considered just a nuisance to be trapped. They play a role. An important role that would be vacant if not for them.

I hope we can continue to call the return of the American Beaver a success story and witness more success stories for other creatures we share our planet with in the future. All creatures play a role…either predator or prey. Keystone creatures play a vital role for all other creatures by creating and protecting habitats. You remove the keystone and the whole ecosystem changes drastically.

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Winter Blues

Article and photos by Linda Hagan, Maryland Master Naturalist

The winter season can cause many people to have the “Winter Blues” due to low light levels, lack of sunshine, the burr of the winter cold and being stuck inside for weeks.  Many people become “Snowbirds” and migrate to warmer areas during the winter months, returning in the spring. And, yes, many wish the winter season away, but others like myself enjoy the changing seasons and what each season has to offer.  We humans are mammals after all, and like some mammals, some of us hibernate during the cold months.  Others like many birds migrate South.  Still other mammals, birds and humans stick around and have learned how to cope with the harshness of the winter landscape.  I am one of those humans who has learned how by embracing what it offers me.

Winter is a great time to catch up on your reading.  I don’t know about you, but I have piles of books to read and the spring/summer/fall months I am too busy doing other things like gardening, camping, mowing grass, and spending time with my grandsons.  The days are long and filled with other things that take up my time.  Winter is a great time to read some nature books and learn about those creatures we share our planet with. Plan a trip to one of our wonderful State or National Parks.  If you can, visit one of them during the winter months. They are less crowded and if you go to a place such as Yellowstone you will be in for a winter treat of amazing beauty.  You may also get a chance to see creatures like the Gray Wolves that might be harder to view during the summer months. I recently saw a television show where people were lined up with their cameras in hand just hoping to get a glimpse of a wolf pack crossing a snowy ridge. What a sight that would be!

Winter can offer many joys at home too.  What about filling a bird feeder or several bird feeders to attract birds like Cardinals, Bluejays, several species of Finches, White Throated Sparrows, Chickadees, Tufted Titmouse and many others.  Buy a bird book for identification and keep a journal of what visits your feeder. If you hang a suet feeder you may also get visits from birds such as the Red Bellied Woodpecker, Nuthatches and the Downy and Hairy Woodpeckers…which can be challenging to tell apart, so keep that bird identification book nearby.  Also consider keeping a pair of binoculars handy, or I prefer a monocular which I find easier because I only have to focus one eye piece instead of two.  Bird Watching opens up a whole new world to explore and you can do it from the comfort of a chair by a window with a bird feeder nearby so you can “watch the birds”. Believe me, there is nothing more beautiful against a back drop of snow than a beautiful bright red cardinal. They can cheer any Scrooge.  I have dozens of them visiting my feeder now.  As I sit and write this blog article, I can’t help but look out at my bird feeder to see what is visiting and laugh at the antics of the squirrels as they are scolding the birds for hogging the feeder.

Winter is also a great time to go to a park like Assateague National Seashore right here in Maryland.  I prefer the cooler months to visit  because during the warm months the biting insects can be bothersome. Regardless of what time of year, there is always an abundance of bird life!  It’s great to walk around the marsh and other trails and yes the Assateague Horses are always there. Just remember, they are “wild” and can bite or kick, and it is their home, not ours.

Now don’t forget about other wildlife who are looking for a helping hand during the cold months and can also offer great entertainment. I am referring to squirrels….yes, those furry little critters that live in the woods but are also common in towns, cities, suburbs and near apartment complexes.  These small acrobatic creatures have learned how to live near humans.  They will raid your bird feeders no matter how much you try to discourage them and, honestly, I find them lots of fun to watch! You can buy different feeders for squirrels and provide corn, peanuts and seeds to help draw them away from your bird feeder or buy a “wildlife” block that attracts the squirrels as well as other wildlife and birds. They come in 20-pound blocks that last longer then what you put in a bird feeder. Plus they help provide complete nutrition that wildlife needs to survive the winter months. If you have deer that come into your yard you can also buy “deer” blocks, but I have found they will also go to the wildlife blocks just as well. It might help keep them away from your shrubs. So you get to enjoy wildlife without leaving the warmth of your home and it didn’t cost you a ticket to go to Florida.

I enjoy walking in the winter.  You don’t get all sweaty like you do in the summer.  I’m not hurrying to get finished so I can find a cool place.  There are hidden wonders to be found that you don’t see when they are hidden behind the camouflage of greenery during those warmer months. It’s a great time to learn how to “saunter” as John Muir advised people to do. He said, “I don’t like either the word [hike] or the thing.  People ought to saunter in the mountains -not ‘hike!’”  I have learned to saunter, to slow down, and look closer at nature.  Even during the starkness of winter there are things to see.  I enjoy taking photos of nature and since I’ve grown older I don’t enjoy rushing anywhere, so sauntering suits me!  There are glorious finds when you take a closer look.

Just recently I discovered we have beaver living nearby. I’m sure they have been there awhile but it was only during the winter I was able to discover where. In the summer I wouldn’t walk in the overgrown meadow near the stream, but I did one winter day. I was rewarded by finding the beaver dam and it’s lodge plus still standing trees that had been chewed and would be used for food and maintenance of his home.  Only in winter would I have ventured through those high grasses now laying flat. 

Another morning I was looking at dew drops that hung like jewels on everything they touched. They mirrored the trees and blue sky through their tiny prisms. I found a hornets nest hanging from a tree, now torn, but revealing the inside of their home and the marvelous workmanship of these creatures we try so hard to avoid. 

I know not everyone likes to drive when it’s icy, but I think we can all agree that the beautiful crystal shimmer of ice hanging from the trees, grasses and buildings is breath-taking.  One morning when it was safe to venture out I started looking at the ice that had fallen from the trees, each shard looking like glass. Some pieces you could look straight through and others were like frosty panes of glass with cell like patterns.  The walk to the stream, seeing the ice that hung on the grasses along the bank which looked like dancing ladies to my eyes, and the rushing water soothed my soul. 

My wish for you during these winter months is that you will take the time to look and appreciate its uniqueness.  Each season, like the seasons of our lives has beauties to see and enjoy. None should be wished away.  As a child I use to wish the school season would be over, or Christmas would hurry and come, or I could be grown up. My mother would say “stop wishing your life away.”  Those words ring so true. Every time we wish for another season we are wishing months of our lives to pass by too quickly. Let’s all take the time to enjoy nature’s glory in every season. We can walk in our backyards or watch from our windows as the seasons change. 

Pick a special place like Fountain Rock Park to walk and see how it changes each season you visit.  Take a camera along and get down and look at things you pass by all the time. It is a marvelous, inspiring and glorious awakening that nature will reveal to you…if you take the time to look.  Take the time to enjoy what each season has to share. If you do you will find even in winter there is much to see and it may just help chase those “Winter Blues” away.


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Northern Map Turtle

Graptemys geographica

Article and photos by Linda Hagan, Maryland Master Naturalist Intern

The Northern Map Turtle is an aquatic, fresh water turtle that inhabits large rivers, streams and lakes.  They spend much of their time underwater although they do require abundant basking sites, but they are shy and will dive for safety at any disturbance. Map turtles usually forage for food in the morning and late afternoon and prefer to bask at midday. 

Northern Map turtles get their name from their appearance.  The carapace (top shell) has a shallow but definite midline keel.  It is olive colored and has designs that resemble a map, some say the lines look like waterways or topographic lines on a map.  The lines are yellow to orange in color with darker colors in between them in greens and browns.  Any pattern may be obscured by dark pigmentation in females or algae growth on the carapace. The skin is olive to brown black with thicker yellow to greenish yellow stripes on the skin of their face and limbs.  The skin design can be more noticeable due to the fact the shell can fade with age. The plastron (bottom shell) is pale yellow in adults but juveniles have a black pigment along the scute (plate) line. The Northern Map Turtles also have a large jaw surface which give the appearance of light colored lips. 

Map turtles assemble in groups to hibernate and spend their winters in deep, riverine pools where the water is cold and has a high level of oxygen.   There they will lie motionless on the bottom fully exposed.  They are able to breathe underwater because they take up oxygen through permeable skin that is well supplied with blood.

Male Map Turtles have narrower heads, oval-shaped carapace and longer, thicker tails than the females do.  The females are larger than the males with a carapace measuring up to 10.5” compared to the males with a 6.2” carapace. 

Breeding takes place in both spring and fall.  Nests are usually built on open, sandy  beaches or sand bars rather than wooded areas.  The egg laying process can take many hours, beginning at nightfall and lasting until early morning.  The female will lay 10-13 eggs per clutch and usually lays two clutches a year.  Map turtles have temperature dependent sex determination.  Warmer temperatures produce females and cooler temperatures males.  Males reach sexual maturity at around 4-6 yrs of age but females can take more than 10 yrs to mature.  The predators of their nest sites are raccoons, skunks, foxes, and river otters.  Gulls, crows, grackles and red-winged blackbirds will eat hatchlings. Adult turtles can also be prey to skunks, raccoons, coyotes and opossum. 

Map Turtles feed on a variety of food sources.  Algae, vascular plants, dead fish, snails, clams, crayfish and a wide variety of insects. 

Where many turtles such as the Eastern Box Turtle can live 75 yrs or more, the Map Turtle usually lives from 20-25 years of age.  There are 13 species of Map Turtles.  The Map Turtle we have living at FountainRock is a Mississippi Map Turtle named “Kohni” who came to live with us in 2014 on a rainy spring day.  When counting Kohni’s scutes at the time of her arrival it was estimated she was around 15 years of age.  Come visit beautiful Kohni and see why she is called a Map Turtle. 

The Northern Map Turtle has been listed as endangered in Maryland because of its restricted range.  Threats such as water pollution, waterfront development, vehicle traffic, boat propellers, habitat destruction, siltation, dams, and collection for the pet trade are all causes of the endangered status the Northern Map Turtle faces.  It is up to humans in the private and public sectors to join together to protect and restore habitat if we want to see these beautiful turtles continue to be part of our diverse ecosystems.

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