Field Trip: Mud Pond in Williston

Grumpy old cattail herma

Mud Pond has been on my bucket list for a few years now, since I heard about the microburst damage there. Last week I finally made the trek out there with my sister, and wow was it totally worth it. We hopped off the trail after about a 100 yards following a set of gray squirrel tracks. It broke out of the hemlocks into the open of a red maple swamp. We quickly switched to a gray fox trail, which crossed fisher, mink, long tailed weasel, and red fox! The tracking was totally amazing with a ton of different habitats woven together.



The fox lead us down to a creek which ultimately drained into Mud Pond proper. There's a great mix of American elms and green ash in with the red maples. The ice on the creek was gorgeous and we spent a while photographing it before heading out on the dam to explore the old, abandoned beaver lodge. The mud caking the outside had largely washed away and we could poke our heads in to see the feeding platform. It's not often you get to look inside an old lodge, so that was wonderful. The rim of the pond is a dense tangle of cattails and sedges that as the land slopes up grades into an even denser tangle of alders and then maples.

Possibly a goldfinch nest in a speckled alder

The highlight was towards the end where I saw a long swoop carved gently into the snow. It started in a little patch between hemlocks about 4 feet before ending in a flurry of little squirrely tracks. These circled around themselves for awhile before disappearing up a tree. I've never seen definitive flying squirrel tracks, so it made the whole day worth it. Plus there were several bird splatterings on the snow filled with snow fleas (a type of springtail)! We wound up getting completely and utterly turned around for some reason, but eventually made our way back to the car.

Owl feathers

What: I found these owl feathers strung up in a yellow birch sapling at Rock Point. The feathers had been plucked from the body of the bird (there was still some flesh attached to some of the cluster of feathers indicating it hadn't just molted the feathers). Here's my process of elimination for identifying them to species:

Detail showing "fuzz" on the feathers

• Owls have fuzzy feathers along with a leading edge of "prongs" that make it look like a comb. These together channel air over the feather (black box of physics for me) that allow the bird to fly in utter silence. Raptors (Falconiformes) have this as well, but not nearly as well developed as in owls (Strigidae). 
• In Chittenden County, there are records of 10 owl species, according to eBird.org. Six of these species are extremely rare (barn, snowy, hawk, great gray, long-eared, and short-eared owls). This leaves me with four probable species: eastern screech, great horned, barred, and saw-whet owls.
• Using the book Bird Feathers and the online Feather Atlas I was able to narrow it down to further. The largest feather is a flight feathers (one of the secondaries on the wing). Flight feathers are asymetrical, have a bend when looked at both in profile and head on, and the tail edge of the feather curls up slightly.
• The white bands on barred owl flight feathers cut straight across the feather. These were just white blotches on the trailing end of the feather.
• Barred owls also have 2 distinct colors of brown. 
• Screech owls also have 2 distinct colors of brown on their primaries. I've also seen these before and they tend to have an orangey/reddish hue to them. 
• The white on each feather makes a clear triangular shape
• Given size (about 3.5" long), color (one solid color of brown), and pattern of white dots, it seems like Northern saw-whet is the best match.

We have a pair of barred owls that we see and hear frequently around Crow's Path. My guess is that the saw-whet was eaten by the barred owl, which are apparently common predators of saw-whets. I looked around briefly for pellets but didn't find any. Pretty neat stuff!

Where: Rock Point in Burlington

Other notes: Great resources are the online Feather Atlas and the book Bird feathers by S David Scott and Casey McFarland

Possum and more feet

Right front

Left rear

What: Brooke alerted me to a roadkill opossum (Didelphis virginiana) on East Ave the other day that I picked up. I like to poke fun at these bizarre critters, since they're one of the most retched creatures we have. They amble in a dopey, almost drunken way, are often drooling, and are frequently the victims of frostbite, which reeks havoc on their ears and tails. I once watched a possum lick my fence for about 15 minutes. I got close enough to touch it, but not close enough to have any idea of what it was licking. They're certainly a different kind of beast.

Frost bite on ear

Fun facts about the Virginia Opossum:

• Possums have a super short life span (a 2 year old possum is ancient)
• They have 50 teeth (dental formula: 5134/4134)
• Possums don't "play" dead but actually become catatonic. It's an involuntary response, the crescendo of which is the expulsion of a foul smelling liquid from their scent glands. I'd assume that this deters any predator from wanting anything to do with eating the animal (it also starts drooling, will urinate and defecate as well as lower its temperature and heart rate). 
• They only have awn hair, which explains the raggedy look of their coat (somewhere between the insulative down hairs and the coloration hairs we collectively call the pelt and individually the guard hairs)
• Only the females have pouches (and they're super small)
• Possums frequently get frostbite here in Vermont. They're at the northern most extent of their range and have naked tails/ears. Like cardinals, they have moved their range north following urban centers of people.
• Males have a scent gland on the chest that gives the fur in that spot a gross yellow color
• They are not winter mammals, and can lose almost half their body weight during the winter
• Sperm is paired and doesn't swim straight if single
• They're essentially immune to snake bites
• They're total scavengers (which might be why I have such an affinity for them) and apparently have a rapacious appetite for calcium so frequently eat road kill skeletons
• They supposedly even will kill rats, but mostly they scavenger for invertebrates and carrion
• They have a very very slow metabolism (unlike shrews) and move much slower than most animals their size

Frost bite on tail

Ecological notes: The frostbite they frequently get doesn't matter all that much, nor is their much selective pressure pushing them to adapt to the winter since they live such short live (rarely living more than one full winter). They are continually pushing their range northward. Young possums can hang by their tails, but adults can't.

Where: East Ave

Other notes: Opossum comes from the Algonquian word "opassum" which translates roughly to "white animal". The word was first used in 1608 by Capt. John Smith. His description of "possums" (the 'o' was dropped in writings as early as 1613), is simple and alludes to the oddball-ness of the creature: "An Opassom hath an head like a Swine, and a taile like a Rat, and is of the bignes of a Cat. Under her belly she hath a bagge, wherein shee lodgeth, carrieth, and sucketh her young."

Other posts with photos of animal feet in them:

• Raccoon
• Red squirrel
• Gray squirrel
• Mink

More feet

Front left foot of a mink

What: A friend up in Fairfield had a mink (Mustela vison) kill all of her chickens while she was away on vacation. Her neighbor's dog subsequently killed the mink. I went up on Sunday to pick up the mink, which is in great shape, save a puncture on its back and snout. I see their tracks often, so it was great to get to look up close at their feet - you can actually see "fingerprints" on each of the toes! Like all members of the weasel family (Mustelidae), mink have five toes on both their front and rear feet. (insectivores also have the same number of toes but are considerably smaller). The toes are webbed maybe half way up the digit (mink are highly aquatic), and their toenails were incredibly sharp.

Hind feet (right foot is on bottom) of a mink

Where: Fairfield, VT

Fallible wild animals

More photos by Zac. Penny included for scale

What: On our tracking adventure at Bread and Butter Farm, we were also impressed at the density of coyote sign - they must be snacking on all them li'l rabs. We decided to trail one of the paths for a ways. Pretty quickly, we started noticing blood spots in quite a few places along the trail. Female coyotes are monoestrous (having only one period of "heat" per year). It's relatively short, about 3-5 days and happens sometime between late January and early March, so we got lucky in our timing. The females will scent mark with their urine (which has blood in it). It shows up as small reddish yellow drops on the snow. The female we followed seemed to be on a hunting foray, traveling in mostly straight lines with occasional detours to investigate something that caught her attention (for as long as we followed her, she was unsuccessful in her hunt).

Zac and I both wound up post-holing while trailing her along a small brook that was frozen over. I tend to take clumsiness in humans as a given, but never expect it from wild animals. It's always jarring to see a squirrel miss a branch it's jumping to and fall to the ground, or watch a beaver trip as it's stepping over a rock, or catch a cottontail running into a fence. In this case, not more than 30 yards from where both Zac and I broke through the ice, we saw the tracks in the image above.

It appears like the coyote postholed, then slipped with her right front foot. The track just below the dark circle (the posthole) is her rear foot swinging out wide to steady herself. That 3' provided us with a hundred little stories and questions that we only began to answer as we made our way along the trail over the next half mile or so. It's always refreshing to remember that every now and again wild animal show their fallibility.

Ecological notes: In Centennial Woods there's an abundance of fox (red and gray) and deer, but no coyotes and only a very few rabbits. It made me wonder if there was a correlation between the presence/absence of those species. I found some interesting studies that look into the relationships between these species (as well as bobcats and even Lyme disease). Here's a summary of what I found:

• Coyotes eat gray foxes (not sure I believe this, or at least that this has a significant impact on gray fox populations)
• There's an inverse correlation between fox and rabbit populations. Where cottontails are in great abundance, red foxes, an obligate generalist, will shift and specialize in hunting them (study)
• Bobcats prefer rabbits and rodents and will eat deer second (study)
• There's an inverse relationship between fox and coyote populations (coyotes apparently bully foxes out of their territories, called interference competition study, another study found that a third of kit foxes radio collared had been killed by coyotes, study)
• As a result, foxes can be found on the edge of a coyote's territory, but rarely within it
• Foxes out-compete coyotes in areas where human densities are higher
• Many predators will kill other predators (canids, it turns out are the most likely predators to kill other species of predators: study)
• More foxes=less Lyme disease, more coyotes=more Lyme disease (study)
• Red foxes have a significant impact on the European Roe deer, but those are much smaller than our native deer and it's likely that no such correlation exists
• Coyotes have a significant impact on deer populations (study)
• Coyotes are more successful in hunting deer in harsh winters (study)
• There's no hunting allowed in Burlington, so deer populations may be higher here as a result
• Deer seek refuge under conifers during winter for warmth, both habitats provide an abundance of hemlock cover, however

Rabbits are what they eat

Rabbit debarking bittersweet (all photos in this post by Zas Ispa-Landa)

What: You are what you eat. And in this case rabbits are a whole lot of things. Zac and I were impressed at the abundance of rabbit sign (from the introduced eastern cottontail, Sylvilagus floridanus, as opposed to the native New England cottontail, Sylvilagus transitionalis) when we went tracking on Saturday down at Bread and Butter Farm in Shelburne. We even spooked a cottontail as we walked past the driveway. Rabbits seemed to prefer shrubby non-natives, or at least those were the most prolific species in the area and so were the most foraged upon. We found feeding sign (debarking and/or twigs clipped) on forsythia, common buckthorn, barberry, domestic apple, honeysuckle, staghorn sumac, and oriental bittersweet.

45o angle snips on twigs, charateristic feeding sign from cottontails
on woody species (forsythia in this case)

The story got even cooler at the end of the day when we found another high traffic area for cottontails under the powerlines. Buckthorn predominates in that area and the rabbits must have been eating fallen buckthorn berries as their urine was died blue (image on the right is blue tinted urine, on the right is more typical orange). Buckthorn berries are unpallatable, if not inedible to most things so the berries persist into late winter, when they become a last resort for many winter active species.

Ecological notes: Many plants contain phenolics (tannins, which cause the dry taste in wines, the bitterness in aspen bark) as a defense against herbivory. During spring and summer these are concentrated in leaves and flowers, but during winter they are translocated to the bark. Animals have a variety of ways of dealing with these phenolics (e.g. beavers will soak witchhazel before eating to leach tannins, birds and will eat clay, which absorbs phenolics). Buckthorn (Rhamnus cathartica) is high in phenolic compounds. Rabbits presumably can handle the phenolics by breaking them down in their kidneys, or maybe eating clay. The anthocyanins (pigments in the fruits) are also excreted in the urine. I'd assume that eating buckthorn fruits later in the season gives more time for the tannic acids to break down and makes the fruits more palatable. That's speculation though, and I couldn't find any articles to confirm/deny that.

At the end of every trail...

What: Brian came downstairs yipping about a red fox in the parking lot. A minute later Meryl came down equally excited. We threw on our shoes and headed out into the beautiful snow. We picked up the tracks circling along the edge of cedars then along the powerline substation by UVM Facilities office and Centennial Field. In the photo below the fox demonstrates a near perfect direct register trot. In this gait the animal's rear foot lands exactly where the front foot landed. The 3rd, 5th, and 7th prints appear wider where the animal slips from the direct register just slightly. The front foot, which is larger (as with all canines) and appears under the imprint of the rear foot, is offset to the right, where the fox was probably looking to the right (up the road to East Ave).

We came to a very very small crack in the fence that it had scooted under. Weirdest thing is to think how that little opening got there, as it seemed deliberate. Could the foxes have worked up the fence over time? It'd be tough for even a human to bend that fence. The fence is other wise in perfect shape and it's on the side that doesn't have any traffic so it's hard to imagine it accidentally getting formed. Regardless, it makes for a nice escape hatch (as when being pursued by a pair of humans).

On the east end of the substation, there's another gap in the fence that the fox slithered through before making its way down the rocks towards the dumpster. See if you can spot the fox in the image below. Brian and I watched the fox for a bit tugging away at the ground before slowly stalking up on it. 

As we got closer, it looked like it was trying to get under the plow. When we got about 35' away we scared the fox off and were able to investigate what it was investigating. We found a dead squirrel tangled in a pile of trash (smelled really really bad). The fox ran around the fence and hid under the building you can see in the above image.

Where: UVM Facilities/Centennial Field

Other notes: As we approached another fox of equal size got spooked and headed over to the south where the mulch piles are. The weirdest thing was that the fox was white. Or rather, it seemed like a darker colored fox that had its coat covered in snow. Brian and I were both covered in snow after being out about 30 minutes, so not unlikely, but still seemed weird - albino foxes in CW?

Red Squirrel Tracks

What: One of my favorite finds of the day on Saturday was a beautiful set of red squirrel tracks that had been preserved on top of the snow. Compressed snow melts slower than light fluffy snow, so you can often find tracks embossed, or raised in the snow as the surrounding snow melts away. Here, we found a whole set of red squirrel tracks that looked like little ice buttons sitting on the surface of the snow. Once we spotted these I started noticing similar tracks everywhere - particularly the raised ridges of cross-country ski tracks. Sorry for the high contrast photos, but it was about the best I could do with the lighting (I had to ramp up the contrast to make them more visible).

Here the squirrel is moving away from the camera. It's two smaller front feet land in the middle, slightly offset from one another. The larger rear feet land after the front feet pick up and on the outside, in line with each other. Red squirrels tend to land with their feet more offset than gray squirrels. I think I learned this from Jim Halfpenny's tracking book: animals that spend more time in trees (e.g. gray squirrels) land with their front feet in parallel (like they'd been while perching on a branch) and animals that spend more time on the ground (e.g. rabbits) land with their front paws far more offset.

Where: The Intervale

Goodbye snow

What: I went for a wonderful walk on Saturday morning with my friend, Kate, to check out her topbar beehive. Her bees were reluctant to come out when we first arrived, but by the time we left the sun was out and it was about 43 degrees. Her hive is in full sun and has a dark cover, so it must have warmed the hive up much higher than that. Her bees were flying with great relish! I can only imagine the relief of being able to fly after spending a month and a half cooped up in darkness.

Bee flyling, yellow blotches on snow are their poop

They spend their time on warm winter days cleaning shop and making poop flights, for lack of a better term. The little yellow splotches in the photos immediately above and below are bee poop. We were both surprised at how much poop a single bee can poop; it was like watching a great blue heron or bald eagle fly over head and unleash a torrent of poop. 

bee poop on surface of snow

Inside the hive, bees shiver to maintain heat. To fly a bee needs to be at about 85oF. It'll shiver and spike it's temperature to about 100o before taking off. If the weather outside is too cold, the bees won't make it very far. But their temperature can drop pretty low before they'll die. Bees on the inside of the hive that are on the outside of the cluster can have body temperatures as low as 41o. Below is one unfortunate bee. The dark bodies of the bees absorb the heat from the sun, so many had melted down into the snow.

When we inspected a couple of the bees that had flown and landed on the snow we found some varroa mites, which Kate wasn't too happy about. They look like shiny water pennies (a type of limpet). Below is the best my camera could do, they're about as big as a grain of sand so they're hard to spot.

Where: The Intervale

Pine borers

Posted by Aaron Rosenbluth. Aaron is a sophomore from Cleveland, Ohio studying Natural Resource Planning and Economics. He loves being in the outdoors and is happily a member of the UVM outing club!

What: Two months ago I was in Centennial Woods leaning against a fallen tree taking notes. The sun was out and I couldn't have been happier listening to the summer grasshoppers sing and birds above me chirp. After almost a half an hour out there, I looked behind me at the tree I was leaning against and realized I was leaning against a phenomenon that I've seen countless times over the years, but have never really thought twice about. What I saw was a simply massive maze of tunnels/passages in the wood. The tunnels weren't very deep down - just under the bark layer - about 1cm deep, but it was a fascinatingly huge and sprawling system. I figured these tunnels were created by some sort of insect species, but which one and how and why?

After some preliminary research I quickly realized what type of species I was starting to investigate; species within the realm of wood-borers, or species which eat and destroy wood (Xylophagous species, from Greek "xylon" for wood and "phagus" for eater). These species range considerably in their characteristics (as well as richness, with over 10,000 species of wood-boring insects identified).

• All make unique patterns or “galleries” where they live and lay their larvae, 
• all produce and leave behind unique types of frass (excrement from eating wood), 
• all prefer different species of wood to bore into, 
• and all prefer different levels of health in the tree's which they choose to bore into. 

Once larvae have completed development, new adults will chew an exit hole through the bark and emerge. These exit holes are either round, D-shaped, or ovular. Typically, these wood-borers are insects and arthropod species (beetles, moths, ants, bees) whose larvae are laid in and subsequently mature under the bark layer of trees.

After realizing the tree I was leaning against was once home to massive borer community, I looked around the area (a stand of conifers, mostly white pine and hemlock) and was surprised to find that most of the downed trees in the area had once been host to this same borer species. After researching with Eiseman and Charney's Tracks and Sign of Insects and many hours of poring over internet databases, I was unable to come to a conclusion on exactly what species of borer did this, however I did come to the conclusion that it was some sort of bark beetle of the Curculiondae family within the sub-family Scolytinae (linked at the bottom of this posting is an official Vermont State report on insects which likely contains the correct species). These beetles feed on the cambium layer of trees, creating distinguishable patterns in the inner bark and outer sapwood. It is unlike bark beetles to bore deeper than 3mm into the sapwood layer of the tree, which matches what I observed in my tree. Most commonly, bark beetles will attack a tree that is already injured or diseased, often killing it in the process.

The most basic bark beetle gallery begins with the creation of a mating chamber, from which a female excavates a linear tunnel of uniform width either perpendicular or parallel with the grain of the tree (mine went parallel). On either side of the tunnel, the female creates small little niches and lays an egg in each one. I was able to see these niches in my downed tree species (these were in white pine, Pinus strobus); they look like tick marks that are evenly spread out following the main tunnel (see image above).

Ecological Notes:
Wood borers serve the ecologically keystone task of facilitating tree decomposition by creating holes and channels in the woody tissue, phloem, and bark of the stressed, diseased, or dying trees which they feed on. This allows for fungi to enter the tree and begin decomposition.
http://www.vtfpr.org/protection/documents/FullVersion2009ConditionReport.pdf

Feet & all those dead squirrels

What: I was driving home from Sterling College last night and I hit a young male red squirrel (Tamiasciurus hudsonicus). I felt terrible, but at least it died immediately. I scooped it up and brought it to my CCV Natural History course today to skin with my students. It was neat to be able to see the paw prints up close, to be able to see the palm pads in such detail. All rodents (even beavers, muskrats, mice, voles, capybaras) have five toes in the rear and four in the front. Red squirrels spend a lot more time on the ground relative to grays (Sciurus carolinensis). On the ground, the front feet of reds tend to be offset far more than grays. Think about an animal who spend all that time "perched" on a branch with its feet side by side - when it runs along the ground its front feet keep that side-by-side pattern as seen below.

Red Squirrel                  Gray Squirrel
(ground dwelling)         (tree dwelling)
 H     H          H      H       /\
     f              f  f         ||  H = hind
   f                             ||  f = front

This of course is a tendency and not always true. So in general animals that spend more time on the ground tend to follow the pattern or red squirrels, with front feet landing offset, and animals that spend more time in trees, like gray squirrels, land with feet side-by-side. One of the things reds are doing with all that time spent on the ground is harvesting mushrooms. Look in a stand of hemlocks for mushrooms lodged in the crotch of a branch, left out by red squirrels to dry for a winter supply.

Rear feet, five toes, long flat foot

Front foot, 4 toes, smaller dexterous digits

Ecological notes: Red squirrels spend this time of year in search of a territory to defend over the winter, when food resources are drastically reduced. Fall dispersal of yearlings is always a rough time for animals, with lots and lots more road kill this time of  year than at others. Below are the feet I got from a raccoon (Procyon lotor) that was road kill just north of Stowe. I surprised at how much fat was stored up in the tail.

Raccoon feet (rear feet on outside, front on inside)

Where: North Wolcott along the Wild Branch