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.

What do foxes eat?

What: A couple nights ago, Meryl, Julia, Brian and I were watching a couple of eastern cottontails chasing each other ferociously around in my backyard. For the 3 or so minutes we watched, one was definitely the pursuer. They would sprint for short periods followed by great acrobatic displays with one or both jumping straight into the air. Their breeding season is March through September, so this might be an early start on staking out breeding territory, a mating ritual between a male and a female, or it could be a late winter food-shortage spat. I'd only ever seen one rabbit at a time in my backyard so I didn't realize that their territories overlapped. I have no idea of gender, nor is there a reliable way of telling without having the animal in hand.

I left some food out to bait so I could get a photo of at least one of the rabbits. For the hour or so I watched the rabbit from my window, it spent about 95% of its time in surveillance mode and the other 5% eating, moving, or grooming. I love the above photo, because it shows those great big back legs and stubby little front legs.

Where: My backyard

Other notes: Eastern cottontails (Sylvilagus floridanus) are virtually identical to the native New England cottontail (Sylvilagus transitionalis), and can only definitively be identified if the animal is dead (genetics or skull morphology). NE cottontail populations have declined since Eastern cottontails were introduced to Vermont over 100 years ago. According to a publication on Eastern cottontails produced by Vermont Fish Wildlife, wildlife agencies and private hunting clubs were responsible for the introductions. Rabbit populations have declined as a whole over much of New England due to reforestation and loss of transitional habitat.

Tree cookies

What: Julia and I had craft night on Wednesday (not different from most nights), and I finally made some good progress on a project I started a few months back. Back in the fall I had gotten a bunch of aspen logs that had been cut along the bike path. I cut it into disks (about 3" diameter) and have been drying it along with sections from beech, white birch, hemlock, and yellow birch. For the disks I wanted to translate photos I've taken into woodburnings of animals that live in and around the beaver pond in Centennial Woods. Last night I made the above disks. I've already finished a chickadee, chipmunk, eastern newt, and mink. I still have the following: great blue heron, honeybees, and wood frog.

Game cam in Centennial Woods

What: When we heard about the proposed development near the section of Centennial Woods next to the Sheraton we thought it would be a great idea to go set up a game cam on one of the nearby deer trails.  We  wanted to capture some of the wildlife traveling through this corridor so that we can show the importance of this area to the development council and the public.  This is a really remote part of Centennial Woods in that no human trails run very close to it.  When we were out exploring it for the first time we found parts of a deer skeleton and we were struck by the unique feeling that this section of the woods has.

Three species crossed the game cam's path during the three weeks we left it out there.  We saw a pair of white-tailed deer (Odocoileus virginianus), an eastern cottontail (Sylvilagus floridanus), and the rare Homo sapiens :).  We were surprised that we didn't get more animals coming through this trail but we didn't bait the game cam and these animals have a very wide home range, so this is understandable.

Ecological notes: This area of the woods is unique because it acts as a border for Centennial Woods.  Borders are special areas in the woods because we see different species composition and activity in these parts.  It is important to protect these areas that act as a buffer zone and provide corridors for wildlife to pass through.

Where: Centennial Woods near the Sheraton hotel

Other notes: You may be able to see the nubs on the buck's head where his antlers will emerge later this season.  It was exciting to examine this remote area that we would have not likely spent much time exploring if it hadn't been for the proposed development.

Here's a map showing where we set the game cam up.

View Game cam in a larger map

View Game cam in a larger map

Vinca, Garlic Mustard and an Eastern Cottontail

What: The patch of woods behind my house (dominant trees are black walnut, slippery elm, boxelder, and and Norway maple, with black cherry, honeysuckle, and common buckthorn in the understory and that is literally all) has about three different herbaceous plants growing in the understory and they form near monocrop patches. The first is Vinca spp. (or periwinkle), which I have growing in dense, impenetrable thickets closest to the walnut (walnuts have juglone in their roots which is known to inhibit growth of other plants). Farther away is a 1-2' tall forest of garlic mustard. The scilla, which I already posted about has pretty much gone through its life cycle before the garlic mustard is up.

Ecological notes: I've long just attributed this overwhelming abundance of garlic mustard and vinca to the fact that this is a heavily disturbed area and so non-native exotics like garlic mustard would thrive. The Vinca was probably ground cover from an ornamental planting. There's virtually no leaf litter (all that's there is from this year) due to an over abundance of earthworms (Lumbricus terrestris), the soils are pretty darn sandy, and there's lots of browsers and not a lot of predators.

But I've also been noticing more and more a rabbit in my backyard. The rabbit's an Eastern cottontail, Sylvilagus floridanus, which, for Vermont, is an introduced species that has largely outcompeted the native New England cottontail. We don't really ever get foxes or other rabbit predators and so I think that the rabbit population might be big enough to essentially be controlling the herbaceous layer. I see them eating violets, dandelion, the grasses, and my blueberry shrubs, but they have entirely avoided the garlic mustard and vinca.

Where: My backyard! Sandy soils, an old plowed field (abandoned in the 70s).

Other notes: I tasted a periwinkle flower and it was okay at first and then had a taste reminscent of black licorice but much worse. I haven't seen any really browse sign on them at all so stuff seems to pretty well avoid it.

Game Cam in Centennial Woods

What: I set my game cam up along a game trail on the southeast corner of Centennial Woods near the Sheraton. My hope was to capture some wildlife images to show who is using this part of the woods (there's a proposal up for discussion of an intermodal transit facility to be built that might encroach on the ecological boundaries of Centennial Woods; the assumption seems to be that no one uses it and that there's nothing there so why not develop it). See if you can tell what's in the photos below. Roll over images to see answer (the first one doesn't have anything but will help you see what's in the second one). The last two are of the same animal. And I know the photos aren't exactly prize winning, but I only had it up for two nights and I checked once. I'll leave it up another couple of weeks and then post what I find next.

Ecological notes: The spot is a cool location in CW because it's one of the most remote sections of Centennial Woods, at least in terms of its proximity to trails. It's also one of the younger patches so there's ample browse for deer and cover for rabbits. I've tracked fishers up and down in this area. There's lots of goldenrod and milkweed blanketed the field. Closer to the woods it grades into a pretty young stand of quaking aspen (almost exclusively), with occasional white pine and white birch.


Other notes: On a recent trip to this spot a friend and I found a deer skeleton and a goldfinch nest. I went back out today and found another goldfinch nest and a cercropia moth cocoon! It would be an incredible gift to the community if UVM extended the boundaries of the Natural Area to include the land that is ecologically contiguous with the Natural Area boundary. Centennial Woods used to be 210 acres of land. It's been slowly cut up for roads, baseball fields, parking lots, powerlines, quarries, hotels, gas stations, and housing developments. At some point we'll regret our decisions and the next generation will never know what they're missing.