Saturday, April 5, 2014

Sapsuckers and sap flow

What: Last week, I was out checking the bees with Zac and Sophia and we noticed that the boxelder looked like it had wet its pants. A few days earlier, Clay had spotted an odd ball woodpecker in our backyard and I thought from a quick glimpse it may have been a sapsucker. When we inspected the "wet spots" on the boxelder, sure enough there were all sorts of little drill holes. We licked the bark and it was delicious.

There are a lot of origin stories about the human discovery of maple sugaring. I'll bet almost all of them are false and created many generations after humans were utilizing syrup. I've got three bets for how humans discovered sugaring:
  1. Red Squirrels: I've watched red squirrels chew little notches in branches of sugar and red maples. I've also watched them return and lick off the sap from bark later.
  2. Sapsuckers: Water can be hard to come by in the winter. Curiosity, particulalry when there's a need for something, runs high in humans. My first inclination when I saw the drill holes and wet bark was to wonder what the sapsucker was after. My second inclination was to taste the sap. I was rewarded with a delicious treat.
  3. Broken branches: Silver maples and boxelders both grow along floodplains. Winter can be rough on trees and without the metabolic activity to heal wounds, exposed wound sites will "bleed" once the sap starts flowing. Early in the sugaring season, when temperatures still drop well below freezing at night, any sap that might flow out of a broken branch can freeze into a sapsicle. The water freezes first and the outer coat is extra sweet. Kids love to suck on icicles and I'll be it was a kid that first discovered these sweet treats. 
I've kept an informal list over the years of species that I've seen sapsuckers tapping. The list this year includes: Black walnut, Red oak, Boxelder, Silver maple, Hemlock, Bitternut hickory, White pine, Norway spruce, Black cherry, and Paper birch.
black walnut with drill holes from sapsucker

Monday, March 31, 2014


What: With the winter pretty sloggy and crummy, I thought I'd replace some of my time out wandering with my game cam. Part of the inspiration to put it back up again was a road kill coyote carcass my friend skinned. Yard and I placed the carcass out near Centennial Woods to see if we might get a video of the gray fox I'd been tracking earlier in the winter (haven't seen tracks from it in a few weeks). With the warm weather we were hopeful. While we didn't get the fox, we did get an even better surprise! A few weeks ago, there was some banter on Front Porch Forum about fisher sightings. This is from March 8:
This morning at around 5:45 I saw a cat-sized critter that had a snout and puffy tail run by between the Centennial apartments and cohousing townhouses. It was a little too dark to see color clearly, though I could see that the fur was at least somewhat dark. At first I thought fox, but then thought fisher. Has anyone else seen one lately?
Someone sent a follow up response on March 9:
I too saw a fisher late last week - running through the woods between Latham Court & Thibault Parkway, headed in Colchester Ave. direction. Same time frame - just before dawn. Kitty owners be aware - keep your lovebugs indoors at night! These guys don't fool around. 
While I've seen fishers and tracked them throughout the area, I was skeptical since I hadn't seen any sign this winter of fishers in/around Centennial Woods. I looked for tracks following the second posting and only saw the regular raccoon, possum, house cat, and domestic dogs. Sam spotted a woodchuck out in our yard around the 15th, so it could have been a sleepy whistlepig checking the weather (woodchuck comes from the Cree word, wuchek, which means, you guessed it, fisher; apparently early whites couldn't tell the difference between the two animals and confused the term).

Not that my video confirms that my neighbors saw a fisher, but it certainly indicates that this is possible. The fisher in the video is most likely a male (males are significantly larger than females, almost twice as big). Males also have much larger home ranges than females (up to ~7 miles in winter, but in Burlington this could be smaller with the abundance of squirrels, particularly red squirrels in and around Centennial Woods), so their spotty presence may be due to patrolling their territory.

We also captured squirrels interacting with the carcass, which was pretty interesting to watch.

Thursday, March 27, 2014

Marcesence - Photo essay

What: One of my students, Kaleigh Wood, posted about marcescence a couple of years ago. Marcescence, which is common in trees in the oak family, fagaceae (e.g. oaks and beeches), is the process in which the leaves die in the fall before the abscission layer completes the process of releasing the leaf from the tree. I think that these trees just have poor timing and cold weather kills the leave. Others suggest that the dead leaves help protect from the cold, water loss due to wind, or deer browse.

The cost of keeping leaves on is that harsh winter winds could rip the leaves off the tree, exposing the branch to insect predators and pathogens. I suppose another overlooked benefit could be that oak leaves are highly acidic and have high concentrations of tannins. There might be incentive not to drop leaves, where the acids and tannins would leach directly into the soil, making growing conditions for the tree more difficult. By retaining the leaves, the acids and tannins may break down before reaching the soil.

 Whatever the reason may be, the leaf petioles on this red oak (growing along the edge of an open field) had been shredded. Some leaves still barely clung to the branches, but mostly all that remained were the frayed fibers of the petioles.

Sunday, March 23, 2014

Turkey Vultures

What: It's FOY (first-of-year) season, and the skies are abuzz with the wing beats of our first returning migrant birds. Apparently, they didn't hear about our record-setting cold weather. I love the first flocks of vultures returning north. They come with the male red-winged blackbirds, the waterfowl (if only our ponds would thaw!!), and the courtship behavior of our over-wintering birds like chickadees.

I spotted this committee of vultures (see my post on collective nouns) over the St Joseph Cemetery on Archibald St in Burlington on Saturday afternoon. There were at least 15 birds.

Over the next few weeks we'll see more and more birds returning to the state. It's an exciting time of year - I'd love to hear what other folks are starting to see as the days get longer and (hopefully) warmer.

Saturday, February 15, 2014

Plastic snow

Sastrugi - the sharp features of a windswept snow surface bordering fractured plates of ice in middle of photo.

When I was younger, I had one word to refer to all that white stuff in winter: snow. As I got older and had more experiences with it, particularly through snowboarding, I realized that not all snow is created equal. Snow taxonomy has a history much older than winter ecologists, and much of the rich language found in cold climates to describe snow has been adapted by winter ecologists (like the Russian sastrugi - above, or Innuit qali - below).

Snow can be grouped into three categories:
  1. Falling snow
  2. Snow on the ground
  3. Surface-generated ice features (like ice needles being pushed up from the ground on wet trails, hoar frost, icicles seeping out of cracks in bedrock)

Qali describes snow hanging from trees (like in the image above). Because our snow the other night fell in a frenzy of blustery winds, there wasn't a whole lot of qali left on the trees. Sintering is a natural process where snowflake crystals fuse together. Sintering can happen due to pressure (like stepping on the snow pack) or temperature (melt-freeze together). Because the snow crystals actually bond together, qali will act as a liquid moving in slow motion. Snakes, like in the image above, are common features in northern woods after a good snow storm. We observed a spot today where the sintered snow had bent down around the rock, creating a perfect overhang for a weasel to pop in and out of while hunting.