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.
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.
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)
What: Finally got around to adding photos. Will post again on Friday. What a beautiful windstorm we had last Tuesday night. Of course this was easy to write from the comfort of my home, free of the flying debris and desiccating winds. Walking around the next morning there was so much debris that had blown down and I imagine that too early fall storms like this take its toll on plants and the still-developing fruits and nuts of things like apples, oaks, and walnuts. These windstorms are probably more helpful for deer and turkey that can't climb trees to get access to apples. The red squirrels (Tamiasciurus hudsonicus; "tamias" means hoarder) seemed extra pissy about it. In about 5 minutes I had collected a 5-gallon bucket's worth of walnuts, that's 5-gallons worth of walnuts the alpha red squirrel could no longer defend from the gray squirrels and beta red squirrel. In the last week since the wind knocked the walnuts down, the red squirrel has seemed less insistent about waking up at dawn to claim his territory, as though the wind was blown from his sails.
Ecological notes: We usually get these gusty Fall storms later on in the season, typically in November. Most of the debris on the ground is likely a result of all the leaves still on the trees, which catch the wind and want to be carried away. By November the leaves have fallen and the wind has a much less dramatic effect on the trees.
A uninfected husk (left) and one hosting a healthy colony of husk fly (right).
Black walnuts (Juglans nigra) have a thick outer husk that's filled with juglone (the same allelopath - toxic chemical - found in the roots that hinders the growth of other species). The chemical stains your hands (and can dye fabrics anything from an earthy yellow to a deep green); it also stains the mouths of squirrels this time of year. The walnut husks that have black on the outside have been colonized by a fly whose larvae eat the husk but leave the nut in tact. I cracked the one below open and found one larvae and two pupae (the shiny dark brown cylinders in the photo to the right).
Gladys eating the walnut husk fly maggots (Rhagoletis sp.)
The shell of the walnut is super tough and sharp (apparently used as an industrial abrasive). It's got a complex labyrinth of groves and channels that the nut fits into, making it difficult to get out large chunks of the "meat" (see photo at top). So it's a lot of work to get at the meat, but if you have lots of time, well worth the patience as it's delicious! It has a sweet minty flavor to it.
Where: All over Vermont
Other notes: Callan and I drove back from Fairfax last Tuesday night. Before we left we heard spring peepers (Pseudacris crucifer, formerly Hyla crucifera) calling. The roads were filled with frogs crossing back and forth. When I got home I was greeted by a chorus of gray treefrogs (Hyla versicolor). The wet weather has brought the young amphibians out in droves. At the fall equinox, the ratio of light to dark during a day is the same as it is during the spring equinox (March 21), which is roughly the time that amphibians first start singing. One theory is that the fall chorus of frogs is from confused young males that are cuing in to daylength.
What: We've got a pair of mourning doves (Zenaida macroura) that started to build a nest in a boxelder (Acer negundo) at the end of our street. I watched the male bring supplies to the female all morning. It was a hot and listless day and the female was yawny waiting for the male to return with sticks (for more on how to identify male vs. female, check out: The Secret Life of the Mourning Dove by Michele Patenaude; in short males are larger, have rosier chests, and have more irridescent heads).
As is evident in the video, it appeared as though the male was testing the strength of each twig/pine needle to be added to the nest by banging it against the ground. Flimsy ones were discarded, sturdier ones brought back. It was fun to watch him pick through the bounty of needles and twigs in search of the perfect ones. I was in and out all morning, but I'm pretty sure the male worked on this for about 6 or 7 hours before my sister and I left the house. By the following afternoon it was abandoned for whatever reason.
A finished mourning dove nest is kind of a disaster so it was hard to tell that it had even been abandoned. I found one a few years ago with Ian Worley and I asked if it was old because it looked like it was in awful shape. He said that was par for the course and the active nests I've seen since then look almost like the birds don't really care at all for craftsmanship or aesthetics. But I guess if you're building a nest in a scraggly tree like a boxelder you build a scraggly looking nest to blend in.
Ecological notes: The nest went unfinished and I think they selected a nearby site over the next couple of days after the video. Last Sunday, Brian was outside and watched the doves attacking a red squirrel. I went out and the red squirrel was coming down a white pine with feathers clinging awkwardly to its mouth. At least one of the mourning doves, and I can't really think of a more docile bird, were going crazy. So the video is from July 1st, 7 days before "the attack". I suspect that they rebuilt and soon after laid eggs. I don't know that the eggs had hatched yet, but my guess is that the doves defended their nest from the red squirrel and the red squirrel might have bit back, but not been actively hunting the doves.
Where: Burlington, VT in my backyard.
Other notes: The red squirrels have been extra bellicose the past couple weeks. It's amazing, I hadn't really seen any of them in my back yard for about two months - just an occasional sighting. But now that the fruits on our black walnut (Juglans cinerea) are swelling, they've been fighting off the gray squirrels like that's the last food source on earth. They start wailing at dawn and don't really stop. What's interesting is that the gray squirrels, though they are certainly submissive, have been equally vocal.
Also, there was a robber fly in my backyard today. I couldn't tell what kind it was nor could I tell what it was eating, but it was fun to watch it devour its meal in fits and starts.
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