Prospecting Wood Duck

I spent some time at the vernal pool on Tuesday collecting invertebrates to feed the spotted salamander (Ambystoma maculatum) larvae we are hosting in my classroom. Thousands of tiny Daphnia sp. (seen HERE) can be easily captured by walking the length of the pool with a fine mesh net just below the surface.

I brought an empty SD card along in order to check the game camera currently deployed on our wood duck box. The box was installed in February of 2016. A detailed account of its installation can be seen HERE. Up until this week, the only wood ducks (Aix sponsa) documented around our nesting box were a pair last spring just before the end of school. I took the camera down at the end of April last year assuming there would be no interest from wood ducks that year. This was unfortunate because when I returned last winter to refresh the pine shavings there were egg shells in the box! The species responsible is still a mystery. A female wood duck would line the bottom of the box with dark downy feathers. The only thing in the box last winter were a few tiny egg shells. With the number of cavity nesting birds in Maine, it could have been anything from a songbird to a saw-whet owl (Aegolius acadicus). Needless to say, I plan to leave the camera up for the entire nesting season this year in hopes of documenting any species using the box.

Mystery egg shells found in the nesting box at the end of last year

A pair of wood ducks swim near the nesting box last spring

Upon arrival at the box on Tuesday, I noticed a downy feather clinging to the top of the entrance hole and fresh scratching near the bottom. This is a sure sign that some sort of bird has been in and out of the box recently. I couldn't wait to get back to the room to see what could be on the camera. 

A glimpse into the life of a wildlife science teacher

After sifting through dozens of photos of an empty nesting box swaying in the wind on some recent blustery days, the photo I have been waiting a year for appeared. A lone image of a hen wood duck entering the box was the only wildlife documented over the past couple of weeks.

A hen wood duck enters the vernal pool nesting box. 

There are a couple of possibilities here. First, this could simply be a hen wood duck checking out a prospective nest site. Her lone appearance and failure to return would indicate that she has not chosen our box. However, the downy feathers and amount of claw marks around the entrance hole have the inner optimist in me hoping that this is not the only trip this hen has made to the box. Could it be that she is coming daily to lay eggs and was even inside incubating when I arrived? I have a feeling that the camera may be pointed a bit too low to pick up a small duck landing on and leaving the nest box. It easily picks up larger movements at water level. I angled the camera a bit higher and am crossing my fingers that this hen will raise a brood here this year. If successful, her ducklings will climb to the entrance hole at just 24 hours old an make the seven foot plunge to join their mother in the pool. In natural tree cavities, some ducklings jump sixty feet or more to the forest floor before being lead by their mother to water. Once down in our vernal pool, they will have all of the invertebrates and amphibian larvae a fast growing duckling could ever need.  The ultimate goal would be images and possibly video of this rarely seen moment in a wood duck's life.  

The American Chestnut

The American chestnut (Castanea dentata) was once the most common and commercially valuable tree in the eastern United States. It ranged from central Maine to southern Appalachia. Legend has it that when settlers first arrived to the new world a gray squirrel could have run from Georgia to Maine without ever touching the ground. It would have done it along the branches of American chestnut trees. These massive trees dropped thousands of pounds of delicious and energy rich chestnuts per acre every year. This is unlike the oaks who generally drop large bitter tasting acorns on a semiannual basis. Their reliability and enjoyable flavor made chestnuts an important food for all wildlife from squirrels to deer and black bears. Humans also relied heavily on this natural food source which was harvested by the ton from the eastern forest every year. They were used to fatten livestock as well as feed families. Holiday songs were even written including this iconic food source being roasted on an open fire. This all changed around the turn of the century when an exotic fungus, known commonly as chestnut blight, was introduced to New York City. By 1930, nearly all American chestnut trees had been wiped from the landscape. Today, the American chestnut is considered "functionally extinct". While the towering specimens our ancestors walked beneath have all vanished, their root systems are still alive within the ground. The blight only kills the living plant above the ground. These last remaining specimens continue to send up new growth, some of which live for up to 10-15 years before finally succumbing to the blight.

The American Chestnut Foundation is a national organization dedicated to the restoration of our eastern chestnut forests. They have been working for decades crossing American chestnut trees with Asian chestnuts that are naturally blight resistant. The goal is to eventually breed a tree that is nearly pure American chestnut but retain the blight resistant genetics of their cousins from Asia. There are signs that they have accomplished this goal but it will be years before a large supply of these trees are ready for the market and mass plantings in our forests. I joined the ACF with my Trees and the Maine Forest class to support this worthy cause and get a really snazzy window sticker. An added bonus to new membership was ten chestnuts harvested from the few productive trees remaining in the state of Maine. We planted them a few weeks ago and have had four come up thus far. Before laying eyes on these seedlings, I had only ever seen one American chestnut tree as a child. Needless to say it was pretty exciting to witness the beginning of what we dream could someday be a towering chestnut tree in the T.A. Forest. While the nuts we received are not thought to be blight resistant, I was still hopeful that we could have some success growing them on T.A. grounds as the ACF does not list any known chestnut trees anywhere in the town of Saco. A ten mile gap between the nearest infected tree is generally good enough to allow a chestnut tree to reach an age old enough to begin producing nuts.

An American chestnut seedling growing in my classroom at T.A. (Photo by Julie Vail)

Today, while working with one of my tree classes in the T.A. Forest, I could not believe my eyes when I took a closer look at a clump of saplings sprouting up ten or so yards form the Eastern Trail. Right there in front of me was a wild American chestnut! I stood quietly trying to talk myself out of what I really wanted it to be while my students conducted their lab work all around me. The more I observed the tree, the more confident I became in what I had found. Finally, I shouted to get everyone closer and we all shared in the excitement of our new discovery. This specimen is just leafing out but the leaves already show the prominently toothed margins and long narrow shape indicative of this species. One of the most confirming features of this specimen is the dead standing tree growing from the middle of the clump of saplings. This is classic for a tree that struggles to grow above ground for more than a decade before being snuffed out by blight. I can't help but wonder how old the root system of this tree is and what the original specimen must have looked like. It is growing beneath some 70' tall eastern white pines (Pinus strobus) that most likely sprouted around the time Thornton Academy was in its infancy during the 1800s. At that time American Chestnuts would have been one of the most common deciduous trees in the area.

New American chestnut leaves in the T.A. Forest (Photo by Julie Vail)

Note the standing dead tree at the center of the clump of saplings. This individual was most likely killed by blight after several years of growth. The small trunk to its left has leaves on the upper half but the lower branches look to be infected.  (Photo by Julie Vail)

While the excitement of finding a wild chestnut growing in our forest has still not worn off, there is a slightly somber feeling as well. Having an infected tree in our area means that there is also blight in our area and our new seedlings are almost certainly doomed. All we can do is hope that our trees can make it long enough to act as ambassadors of an embattled but resilient species. In the mean time, we will allow the leaves on our wild specimen to mature before harvesting them and sending them off to the American Chestnut Foundation to confirm our identification an possibly list the only known American chestnut in Saco.

Touching an American chestnut is like reaching back into another era. It is hard not to wonder what our eastern woodlands would look like today had the blight never been introduced to North America. (Photo by Julie Vail)

Special thanks to Trees and the Maine Forest senior student, Julie Vail, for her amazing photography for today's post.

Busy Morning at the Vernal Pool

While all of the wood frog and spotted salamander breeding activity has come to a close in our vernal pool, there is still plenty of life to observe. We had a great outing during block one today checking in at our pool. Our basic mission was to return some of our classroom wood frog tadpoles in order to keep our tank from overcrowding. Our tadpoles were brought in as eggs early last week and have grown rapidly ever since. The ones returned to the pool this morning have gotten a notable head start on their brethren who have remained in the pool. They are equivalent in size to where they would naturally be in June. This gives these lucky individuals a better chance at reaching metamorphosis before the pool dries up mid-summer.

Wood frog tadpoles ready to be returned to their natal pool

I brought my new camera along for the walk this morning which up until this point has seemed more like wildlife repellent than a useful blogging tool. I'm glad I did as we observed several cool vernal pool visitors. The first sighting was of a beautiful american bittern (Botaurus lentiginosus). Luckily for us, this secretive bird fluttered up into a bush and struck its "concealment pose", doing its best dead stick imitation. Had it just remained motionless at the edge of the pool we never would have seen it. Bitterns are heron-like birds that wade quietly in the shallows feeding on frogs and small fish. To an american bittern, a vernal pool is an all you can eat buffet. Perhaps the coolest feature of the american bittern is its low pitched breeding call. This sound is often described as a rock dropping into the water and is achieved by gulping air into its esophagus.

An american bittern striking its "concealment pose"

After spending a few minutes sitting quietly and observing the pool as a class, amphibians began to appear seemingly out of nowhere. First came a green frog (Lithobates clamitans) resting along the edge of the pool.

A green frog along the edge of the vernal pool

Finally, an especially observant student spotted a spring peeper (Pseudacris crucifer) clinging to to some vegetation in the water. Spotting a spring peeper without it moving first is a feat few can claim. These tiny tree frogs have amazing camouflage and while impossible not to hear this time of year, they are rarely observed.

 A secretive spring peeper in the vernal pool.

Note the sticky toe pads and diminutive size of this adult peeper 

A Bluebird Day

I try to make a point of getting out into the T.A. Forest at least once a week during a prep block to check trail cameras and note any new happenings in the woods. While walking on the Eastern Trail on a recent warm afternoon, I spotted a small flock of eastern bluebirds (Sialia sialis) feeding along the wood line. Bluebirds are insectivores who generally don't show up until insect numbers are sufficient in the springtime. There are always early arrivals and a select few that will actually hang on for the winter here in Southern Maine. I had a small flock hang around my feeder persisting off suet and sunflower seeds last winter.

The flash of blue from the male against the drab early spring landscape is hard to miss and I was excited to see this omen of spring. The timing of the sighting also lined up well with some vocabulary we have been learning in Maine Fish and Wildlife class. Sexual Dimorphism occurs when there is a distinct difference in appearance between male and female members of the same species. Eastern bluebirds are a classic example of a bird exhibiting sexual dimorphism. Mallard ducks, northern cardinals, and wild turkeys are all examples of Maine bird species exhibiting this trait. As with most sexually dimorphic birds, the male eastern bluebird is more brightly colored. It is assumed that this difference in appearance is a result of tens of thousands of years of natural selection. Females selecting for the bluest of males have created the intense coloration seen today. Because females do the choosing, their coloration has not become as intense as the males'.

 A female eastern bluebird perched on a branch above the Eastern Trail

A male eastern bluebird perched on the eastern trail field fence watching for insects along the ground

Crunch Time: Finishing Your Maple Syrup

Nothing strikes fear into the heart of a maple producer more than getting side tracked in the final moments of syrup production and cooking sugar onto the pan. This not only makes a mess that is hard to clean up but also can ruin the flavor of your entire batch. With the amount of preparation and manual labor that goes into sap collection and boiling, losing the batch at the final moments can be devastating. During my high school and college days working at Snell Family Farm during maple season, boiling was an evening ritual that felt like a reward for hard work earlier in the day. We would spend the evening stoking the wood fired evaporator and telling stories. As the thermometer in the finishing pan began to creep toward 219 degrees Fahrenheit (the boiling point of syrup), things got considerably more serious. The finished product had to be removed from the heat and filtered immediately or else BAD things could happen.

A close eye is kept on the thermometer in the final moments of syrup production.

I "finished" our first pint of syrup in class this past Monday and we were all able to enjoy warm maple syrup over ice cream. Saying syrup boils at 219 degrees Fahrenheit is a little oversimplified. In fact, maple syrup boils 7.1 degrees Fahrenheit above the boiling point of water. We generally think of the boiling point of water as 212 degrees Fahrenheit but this is a moving target. Elevation and barometric pressure can affect the boiling point of water and thus move the syrup target up or down.

Using they hydrometer to confirm our syrup is finished

Sap that has not yet reached the sugar concentration required to be called syrup can spoil quickly so it is important to confirm in a couple of ways that the syrup is truly finished. Another measurement that can confirm we have reached syrup is density. A nifty little tool known as a hydrometer uses principles of buoyancy to measure the density of a fluid. Maple sugar producers use a hydrometer calibrated for syrup to help confirm their product is finished. After hitting 219 degrees Fahrenheit in class, we tested our syrup using a hydrometer and confirmed we were done.

Filtering the final product

Finally, the hot syrup was poured through a filter consisting of a synthetic filter paper and multiple layers of cheese cloth. This removes all of the mineral, mostly potassium nitrate, that has concentrated in the syrup along with the sugar. Maple producers call this cloudy mineral sugar sand or niter. Finished syrup should be free of sugar sand and bottled hot to ensure there is no contamination in the container. We let our new jug of syrup cool for a few minutes before enjoying a long awaited taste of spring.

A sweet reward

The Finished Product

Thursday was a long day of boiling but with a sweet reward when all was said and done. I got our mini evaporator set up just below my classroom window first thing in the morning. I teach freshman chemistry during first block and this process provided a great teachable moment. The timing of the boil could not have been more perfect as we are currently learning about classifying matter and separating mixtures. I presented them with a 5 gallon bucket full to the top with what looks like water. It took a little convincing but they eventually believed me that around 2.5% of the bucket was actually sugar! After a bit of brainstorming, their experiment was in place. Maybe, by boiling the sap, we can remove the water leaving the sugar behind? Perfect, it was out the door to start our boil. I can't lie, it was a little anticlimactic after dumping the cold sap into the pan and standing there for a few minutes staring at a lifeless pot. I can't wait to show them the finished product first thing Monday morning.

Raw sap just after collection earlier last week. (Photo by Julie Vail)

Before long it was second block, my Trees and the Maine Forest upperclassmen were arriving, and the pan was rolling. At this point in the boil, the sap was still very dilute but their was a faint yet familiar smell rising from the steam. We had a great time standing around the pan in the ice cold breeze talking about the ins and outs of maple production.

Steam rises from the pan during our first boil of the year. (Photo by Julie Vail)

Over the course of the day, the sap level in the pan would drop and more would be added. Slowly, the sap began to darken and the steam began to smell sweeter and sweeter. Sometime around the end of third block I was able to bring what was left inside to finish boiling in my classroom. People were following their noses into the room to find the source such a sweet aroma. I was bottling finished maple syrup just as the final bell rang. Stay tuned for a post detailing the finishing process.

Our first batch of syrup this season.

The Sap is Running

"Sap's Runnin'" is a comment heard all over the state during this time of year. Our recent warm days and nights below freezing create the perfect conditions for pressure to build up in the sapwood tissues of our resident maple trees. The warm days increase the pressure within the tree forcing sugar rich sap upward toward the crown where it will be used to fuel the production of this year's leaves, flowers and fruit. Cold nights cause a decrease in pressure within the tree pulling water in through the roots and setting up the next day's sap "run". The sugar within the sap was produced the previous year through photosynthesis within the now decomposing leaves, then stored for the winter in the tree's roots. In a way, when you sample some real maple syrup, you could say you are tasting some of last year's sweet sunshine.

Trees and the Maine Forest students tap a campus maple.

Maine is the third largest producer of maple syrup in the United states although our production here in the U.S. is dwarfed by that in Canada who produces 75% of the global supply annually. I worked each spring as a high school and college student collecting sap and producing maple syrup at Snell Family Farm in Buxton and enjoy passing on this springtime tradition to my students today.

The sap began running as soon as the spile was inserted into the tree.

We recently tapped a couple of sugar maple (Acer Saccharum) trees right here on campus at T.A. While there are no wild sugar maples large enough to tap in the T.A. Forest, there are two large specimens growing right on campus that were most likely planted decades ago. Nearly any species of maple can be used to make syrup but sugar maple is preferred due to its higher sugar content and fine flavor. Sugar maples generally produce syrup at a 40:1 ratio. This means we will need to collect about 5 gallons of sap in order to produce a pint or so of syrup, just enough for an ice cream party. It will take hours of boiling to remove the excess water and achieve our tasty reward. Stay tuned for a post detailing the boiling process.

A sap collection bucket hangs on an old campus maple.

Fresh Snow Makes for Great Tracking

Our recent light snowfalls have made for great tracking conditions in the T.A. Forest. An inch or so of snow is all that is needed to document the passing of winter wildlife. Any more than a few inches can make determining the species that left the tracks much trickier. On our latest trip outdoors, my semester 2 wildlife students were treated to a variety of tracks on and around the eastern trail. Gray squirrels have expectedly been out and about on the warmer days, visiting our feeders and digging for acorns buried last fall.

Gray  squirrel tracks in the T.A. Forest

A big part of identifying a track is understanding the way each creature walks, also known as gait pattern. Maine mammals can be broken into four distinct groups including diagonal walkers (dogs, cats, deer), bounders (weasels), gallopers (squirrels, rabbits), and striders (bears, raccoons, porcupines, skunks). The gray squirrel is a classic galloper in that its hind feet often land ahead of its front feet as it runs. The tracks seen above are typical of this gait pattern. It can be hard for beginners to decipher which direction a galloper was headed as we expect the larger hind feet to be in the back. Careful observation of the direction the toes point will clear up any confusion. The squirrel tracks shown above point to the upper lefthand side of the frame. 

 Raccoon tracks in the T.A. Forest

Our most exciting discovery last week was this fresh set of raccoon tracks meandering from one squirrel feeder to the next. Raccoons spend much of the winter in den sites resting and living off of fat stores built up the previous fall. However, any warm snap will bring them out in search of an easy meal. It was neat to get to see such perfect prints in the dusting of snow. This is a great representation of a "pacer" gait pattern as each foot lands in its own spot unlike diagonal walking foxes and coyotes whose hind feet land perfectly in the tracks created by their front feet.

Invasive Plant Species

Invasive plants are non-native species whose introductions can have negative economic or ecological impacts. Unfortunately, some of these species are becoming common on the Maine landscape. Invasive species often outcompete native plants creating monocultures that can require time and money to mitigate. These same species are often less valuable as wildlife habitat.

Multiflora rose hips

My Trees and the Maine Forest students have been studying invasive plant species this week. We spent the class block searching the T.A. forest and identifying as many invasive species as possible. It was eye opening to see just how many of these once ornamental plants have escaped and begun to grow wild along the Eastern Trail. In all, seven species were identified within sight of the trail in less than a quarter mile.

Japanese knotweed along the Eastern Trail

Areas of recent disturbance are the most common places to find invasive plants. Many of them are early successional species perfectly adapted to grow quickly and outcompete the native plants around them. In their natural home ranges, these same species are much less pervasive. Here in North America, they lack the predators and disease that our native species have to deal with. Several of our common invasive species produce berries that can be valuable winter food for songbirds and small rodents (see the common buckthorn below). Unfortunately, seeds are then spread great distances in bird scat creating new infestations.

Common buckthorn berries

Invasive Plant Species Observed 1/6/17:

• Muliflora Rose (Rosa multiflora)
• Shrubby Honeysuckle (Lonicera sp.)
• Japanese Knotweed (Fallopia japonica)
• Norway Maple (Acer platanoides)
• Asiatic Bittersweet (Celastrus obiculatus)
• Common Buckthorn (Rhamnus cathartica)
• Japanese Barberry (Berberus thunbergii)