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A Beaver in Residence at Cranberry Lake Park

Beaver lodge at Cranberry Lake, February 2017

Two years ago, the birding group stepped onto the ice at the edge of Cranberry Lake to see a beaver lodge (above). Pretty cool! But since then, we hadn’t seen much activity around the lodge – no felled or gnawed trees, for example.

Text and photos
by Cam Mannino

Well, an American beaver (Castor canadensis) is definitely in residence this winter! During the first week of January, one appears to have swum through the canal near the end of the lake trail. A good-sized hole had been broken in the ice, leaving large shards on either side. (See below.) And nearby there were definite signs of a foraging beaver!

 

An open spot in the ice with large plates of broken ice around it.

The beaver must have gone right to work gathering some bark to feed on this winter. Beavers eat leaves during the summer, but in winter they feed on the soft inner bark of trees. As my husband and I looked around, we spotted several examples of this accomplished lumberjack’s work! One was only partially gnawed; perhaps a predator or a curious human interrupted its work – or maybe it just decided it had enough fodder and retired to its lodge. [Click to enlarge; hover cursor for captions.]

Beavers have huge, self-sharpening, iron-fortified incisors that they use for this work. The iron makes those big buck teeth very strong and bright orange, as you can see in this taxidermy beaver on display at Seven Ponds Nature Center in Dryden.

A taxidermy beaver on display at Seven Ponds Nature Center in Dryden.

My guess is that our Cranberry Lake beaver (it’s usually a male that gathers food during the winter) came up through the ice and felled a few trees. He then grabbed each log with his powerful jaws, dragging it under the ice and swimming with it out to his lodge. At that early time in January, it was impossible for me to get out on the thin ice to see his cache. What beavers usually do, according to the PBS Nature documentary “Leave It to Beavers” is to  sink a few trees  in the mud beneath the lodge with some of the branches left above the surface.  That allows the beaver to feed under the ice, safe from predators like coyotes. The dark limbs above the surface also help to bring some warmth below on sunny days, keeping the ice near the cache less solid and acting as a marker for their stash of food. Clever little animals! Here’s the lodge two years ago with some trees sticking out of the ice in just that way.

Young branches stuck in the mud near the beaver lodge provide winter food under the ice.

Some of the trunks and branches may just be placed on the lodge for future use. That’s what this year’s beaver appears to have done – though looking through the trees made it difficult to see.

Right now, some of the felled trees seemed to be resting on top of the lodge for future use.

A couple of weeks later, when we’d had some colder weather, I ventured out to the lake edge again to see if any more trees had been felled. None had, but I noticed a long trail of frozen bubbles under the ice. Normally these are methane bubbles released by the bacteria that feed on plants decomposing under the ice. Perhaps this marks some leaves or twigs from the felled trees that the beaver hauled out to his lodge. But of course, the air bubbles could also be coming from the beaver, right? I wondered if this new lodge tenant had ventured out again, but found the ice too thick to break through. Muskrats, which are much smaller than beavers, also swim under the ice in winter, so I’m not sure who or what left this trail.

What appeared to be a trail of bubbles left by the beaver under the ice as few weeks later when the ice was thicker.

Two year old beavers, I learned from the Nature documentary, leave their home lodge and venture out to find an empty lodge that they can rebuild or to build a new one. On a cold day last March, I spotted what I at first assumed was a small beaver swimming toward the shore opposite the lodge. Because of its size, though, I decided it was a muskrat – but now I wonder if my first guess was correct.  No way of knowing really, but I like to think so!

What seems to be a young beaver last March at Cranberry Lake

Young beavers sometimes need to venture out of their lodges more in the winter, because they didn’t fill their larders quite full enough in the autumn. So perhaps the swimmer I saw last March is the new tenant and local lumberjack – and perhaps not.

But if this hydro engineer sticks around, he may be making a few spots in Cranberry Lake a bit deeper each year. Beavers dig deep channels beneath their ponds because the deeper the water, the safer beavers are from predators.  According to the documentary, out west during the 2002 droughts, farmers and ranchers with beavers in their ponds had the only water available for livestock – and of course wildlife gathered at those ponds as well. Beavers keep a lot of water on the landscape by deepening streams and creating ponds with their dams. Of course beavers can also cause trouble with their architectural abilities, flooding roads and human housing, but luckily the documentary explains how clever stewards in Canada are using the beavers’ natural attraction to the sound of trickling water to encourage them to build in safer places.

A fine beaver photo by Blake A. Mann at iNaturalist.org (CC BY-NC)

Usually young beavers don’t mate until their third year. If the beaver who felled the trees this January sticks around and is lucky enough to come across a mate, maybe we’ll discover a whole family of beavers one of these days! I’d just love to photograph a beaver sitting out of the water, but since they usually appear just before dawn or after sunset, no luck so far. Fortunately, a photographer named Blake A. Mann got a lovely photo of one chewing contently on a stick and graciously shared it through iNaturalist.org. He’s definitely inspired me to keep looking!

What’s Under the Ice? Wow! Winter Tadpoles!

The creamy white belly of a tadpole as it feeds at the icy surface of the playground pond.

Winter walks can yield odd – and quite amazing – surprises. For example, how about seeing large tadpoles wriggling just under the ice at Bear Creek Nature Park’s playground pond? My husband and I couldn’t believe what we were seeing at first and neither could members of the birding group last Wednesday – but there they were.

Text and photos Cam Mannino

About a half dozen of them cork-screwed up to the surface, snatched tiny bits of green Water Meal (Wolffia columbiana) floating within a hole in the ice and quickly wriggled back into the depths. Tadpoles in the dead of winter? A first for us and for many of you readers too, I imagine!

A Green Frog tadpole feeding within a hole in the ice  at the playground pond in Bear Creek Nature Park in late December of this year.

After doing a little research, I discovered that this is not as strange as it first appeared. Evidently, Green Frogs (Rana clamitans) lay their eggs from April until autumn. So some tadpoles hatch from their eggs late in the year and overwinter under the ice. It’s not easy. The water under the ice is low in oxygen since no air reaches the surface, and currents can’t mix oxygen into the still water.

When ice forms on a pond, the adult Green Frogs, which is the most common frog at in the Playground Pond, spend the winter resting on the mud below the pond. During hibernation, they can absorb sufficient oxygen through their skin. Their tadpoles, however, can swim and feed during the winter, provided it is not too severe. I immediately wondered, “Why don’t they freeze when the temperature drops?” Well, the North Woodlands website of the North Woodlands Association in New Hampshire explains that it all depends on the harshness of the winter. Tadpoles can move and feed because they have more skin surface related to their body size, or a “higher surface area to volume ratio.” As a result, they absorb enough available oxygen through their skin to power their winter activity.

Winter tadpoles breathe more efficiently because they have more skin surface and less body size than hibernating adult frogs.

Also, though the temperature may be 32° near the ice, as the tadpoles scurry back down into the pond, the temperature rises to 38 or 39° and may be 40° on the bottom. Perhaps that’s why I never got a perfect shot of one wriggling at the surface; it’s just too cold to stay there for long. Or at least that’s my excuse and I’m sticking to it!

By the way, it’s possible that the tadpoles are Bullfrogs (Lithobates catesbeianus) too. They can often take 2 years to metamorphose into adult frogs. But Green Frogs, like the one below, are the ones I most commonly see at the Playground Pond.

An adult Green Frog surrounded by Water Meal plants in the summer months as the Playground Pond

If those tough, wriggly tadpoles survive winter under the ice, they may be getting a jump on the tadpoles that hatch in the spring by being bigger at an earlier date. When the weather warms, the winter tadpoles are ready to metamorphose sooner and grow into bigger frogs. And bigger frogs are better at defending their food territories and finding mates.  Maybe we should take that as inspiration for all of us to keep moving in cold weather!

A Year in the Life of Wildflower Seeds

Collecting wildflower seed here in our township is an enjoyable, labor intensive activity that proceeds through several stages in all four seasons of the year. The flowers do all the work in the summer by producing their colorful blooms.  Then the humans – volunteers and Parks staff –  take over the work in the other three seasons by  harvesting, cleaning and sowing the seed.

Text and photos
by Cam Mannino

Since we’ve just completed the cycle for 2018, I thought we’d share how this ancient cycle of work, organized each year by Dr. Ben VanderWeide, our Natural Areas Stewardship manager, happens throughout the year.

Winter and Spring: Spreading Seed

Ben spreading seed at Bear Creek Nature Park after a prescribed burn in spring 2018.

Readers may remember the blog from last April, when Ben, his stewardship tech Alex Kreibel and I spread wildflower seed in Bear Creek Nature Park. We spent a cool spring morning sowing seed by hand as it’s been done for thousands of years.

For larger projects we might spread seed with a special native seed drill or broadcast spreader attached to a tractor.

loading the seed
When we seed our first prairie plantings at Charles Ilsley Park and Draper Twin Lake Park, we hired Jerry Stewart with Native Connections to do the planting. Here he is filling the machine with seed in 2015.

The seeds we spread take their time for the next few years, sprouting a bit of greenery to catch the sunlight as they grow deep roots. Those roots help them survive drought like all prairie plants. In a few years, when the roots have grown deep, the plants we sow finally bloom and produce more seed. Luckily, nature has also dispersed seeds for countless years. With a little help from us humans through prescribed fire or invasive plant control, native seeds already in the soil will also find their way to the sunlight and grow!

Summer: Blossoms Attract Pollinators

Plants mostly rely on wind and insects – beetles, flies, butterflies – to move pollen from one plant to the next. Pollination is the process by which male genetic material (in the pollen) is transferred from the anther of one plant to the female pistil of another plant (or in self-pollinating plants to pistils on the same plant). If the pollen lands on a compatible plant, it will germinate grow a pollen tube to conduct the sperm to the potential seeds (ovules) in the ovary of the second plant.

Big Bluestem blooms LL
Big Bluestem (Adropogon gerardii) shown here is a wind-pollinated plant. This pictures shows its anthers that produce pollen (bright yellow) and the stigmas that catch pollen (purple and fuzzy).

Wind-pollinated plants like grasses and some trees produce lots of pollen and cast it to the wind, taking a chance that a few grains will land in a receptive flower on another plant. But our insect-pollinated plants use a more targeted method to transfer pollen from one flower to the next. These plants create tempting blossoms full of color, scent, nectar and, of course, pollen to attract and reward pollinators, ensuring that some will be transported to another flower on the insect courier.

We’ll follow the three insect-pollinated plants below, from various parks,  through our seed collecting cycle: Joe Pye (Euthrochium maculatum), Stiff Goldenrod (Solidago rigida) and White Snakeroot (Ageratina altissima). [Click on photos to enlarge; hover cursor for captions.]

Autumn:  Voilà! Fertile Seeds Ready for Harvesting

Here are the same three wildflowers in their seeding phase in the early autumn.  (Please note that two of the three photos below were generously provided by iNaturalist photographers, Ken Potter and mikaelamazzeo94.)

And again, some readers will remember from a November blog  that while nature was dispersing seed through wind, water and gravity this autumn, we humans were out among them, snipping selectively.  Good stewardship requires gathering some native seed so that 1) the seeds get to spots that need native seed, often our active restoration areas where seeds might not reach on their own; and 2) so that the township can save a bit of money on expensive native wildflower seed!

Two volunteers gathering native wildflower seed at Charles Ilsley Park.

Winnowing Out the Seed by Hand – and Foot!

On December 6, 2018 the final stage of our seed collecting came to fruition as Ben taught us techniques for separating the seed from the plants to get them ready to spread. Volunteers and staff gathered at the Parks Department pole barn on Buell Road on a cold winter morning to push the dry stalks through various sizes of screening.

Volunteers in various stages of seed cleaning.

For some plants, that meant wearing leather gloves to rub the stalks against the screen so that the seed would fall into the tub underneath, as we did with White Snakeroot (Ageratina altissima) shown below.

For plants with sturdy structures, like the round heads of Bee Balm (Monarda fistulosa) below, it meant putting a screened box on a plastic  sheet on the floor and actually treading on the seed heads to help loosen the seed!

Ben treading on Menarda seed heads

Once the seeds were separated, they were turned over to Ben’s current stewardship specialist, Alyssa  Radzwion, and volunteer Dena Scher who poured the seeds into bags, labeled them with their scientific names and recorded the information.

Each species of seeds is weighed, labeled and readied for storage.

So here is our haul for this year!

Stewardship specialist Alyssa Radzwion with our stock of wild seed from 2018.

If we have more volunteers to gather seed  (hint, hint…), we could harvest even more in 2019! So consider the ancient pleasure of  sowing seed in the spring, gathering seed on an autumn day, and cleaning seed at a good old fashioned work bee next December. The hum of voices, the laughter, the earthy fragrances of different seeds – it’s a fun way to meet neighbors and help nature grow more of those beautiful wildflowers that are beginning to carpet our restored prairies. And to top it all off, you get to feel like a kid again as you rub, stomp and get covered in tiny silk parachutes!

Dr. Ben covered in the silky parachutes of common milkweed.

Photos of the Week: Making Friends with Winter Darkness

Well, the longest night of the year, the winter solstice,  is behind us, but the nights are still long, aren’t they? We pull the curtains against the blank, black windows as the sun sets, click on a lamp and if we’re lucky, light a fire. Porch lights suddenly glow along our streets. We escape from the dark, fending it off with relief, as if we are warding off danger.

But what if we welcomed the darkness? What if we paused before pulling the curtains and just looked at night coming on? Sunsets around here can be quite dramatic this time of year. Winter is a time to look for “sun pillars,” when vertical beams of light occasionally appear near the sunset, caused by light reflecting on tiny ice crystals suspended in the atmosphere – like this one at our home one winter evening.

And although I’ve never caught “wild geese that fly with the moon on their wings,” I have caught geese flying splashed with the pink of a sunset.

Geese with sunset reflecting on their wings and breasts.
Geese at sunset, Bear Creek

Even a stray chunk of ice can look quite magical when it catches a ray of orange light as dusk settles.

A ray of light at sunset strikes a chunk of ice making a winter landscape

Perhaps we could learn to stand in the dark on a snowy night and listen for the low hooting of the Great Horned Owl (Bubo virginianus). According to the Stokes Guide to Bird Behavior Vol. 3, they mate during the winter. But it’s difficult to hear their plaintive, long distance courting through tightly closed windows and doors. Maybe open the door a crack now and then, set your ear to it and listen.

Seen at Bear Creek in the summer – here in black and white.

It’s mating season for White-tailed Deer (Odocoileus virginianus) as well; unfortunately we are aware of  that from all the heedless deer on the roads. But on foot, it’s magical to see a young doe covered in snow beneath your bird feeder in the evening…

or smile at a pine tree topped by the full moon like the star on a Christmas tree!

Full moon serving as a star atop an evergreen

The intriguing thing about being out in the darkness is that it’s often not as dark as it seems from inside those black windows. The moon and the stars do shine, after all, and anything white – flowers in summer, snow in winter – catches that silver light and reflects it, creating patterns we miss if we aren’t  looking.

So this winter, perhaps we should consider venturing out into the dark – maybe with a friend to feel more comfortable at first. Or perhaps parents can take children out “owling” on a snowy night – and if you’re considering it, have a look at the gorgeous picture book Owl Moon by Jane Yolen for inspiration. Or just take them on a stroll around the lawn while scouting out Orion overhead or other constellations. Even a walk down a long driveway can be exciting on a moonlit night. You can sing to yourself for courage if the possible presence of nocturnal animals makes you nervous; they most often run away at the sound of a human voice. Or if you are intrigued by them, follow fox tracks in the moonlight.

Fox prints on the frozen Center Pond at Bear Creek

Maybe you could make it a personal or family ritual to just take a few minutes once a week to sit with a cup of cocoa, turn off the lights and stare through a darkened window. Watch the moon as it changes; perhaps record its phases on a calendar with your children or grandchildren. Open your door and listen to the song of wind in the pines and how it differs from songs “sung” through bare limbs. If you hear a coyote outside, consider calling your children to the door to listen to their song – and then howl along!

An aura around a winter moon

Perhaps if we can become familiar with the velvet black of a winter night, its sounds and sights, we’ll be more comfortable with it. Let’s befriend the night and see the beauty that lies out there in the winter darkness.

Happy Holidays from All of Us!

During the holiday season, I’m reminded of traditions and the wonderful cycle of changing seasons. Every year we share meals, laughter, tears, and gifts with our families, showing them that they are important to us through the time we spend together. Creating these family moments year after year, memories are passed on and traditions are born.

This holiday season I hope some of the memories you make and the traditions you continue (or start!) include the gift of nature. A simple walk in the woods, skating on a pond, or moments admiring the frosty crystals on the edge of a leaf take on special meaning when we do them with the people we love. Here at Oakland Township Parks, we are thankful for the moments in nature we’ve been able to spend with you. Thanks for reading Natural Areas Notebook and being part of our community!

Ben VanderWeide

Natural Areas Stewardship Manager