April 1 Hill Report: Using the Ears

Ace woodsman Larry Lackey writes:

The vacuum pressure in the main lines, as indicated by the gauge in the sap shed, last week slipped about 1 ½ inches mercury last week, after holding steady for two weeks.  The drop was not unexpected.  Freeze/thaw cycles can nudge taps out of trees.  Critters with sharp teeth – squirrels, deer, maybe coyote? – gnaw on lines.  Are they smart enough to know the tubing holds a sugary beverage?  Are they teething, or just vinyl-curious?  Expiring trees sometimes fall on lines, separating the tubes at the joints.  A day of leak chasing is a bit like a treasure hunt.  The exact nature of chaos is not known until you get out there, but you know it’s out there, killing the vacuum and diminishing the sap yield until we find the source.  With the boiling operation well-staffed and seemingly under control, the Chief of Operations asked me to head up into the bush to track down the source of the vacuum leaks and seal them up.

Morningside and Herbie’s are the two bushes on the south side of Falls Brook, which was living up to its name this day.  A few vestiges of winter ice still clung to the edge of the brook.  Otherwise, the ground was bare and the last of Nebraska Valley’s 2022 modest snowpack was headed for Miller Brook and the Winooski River.   

One tip-off to leaks in the lines are hissing sounds, made by air being drawn into the main lines, tubing or taps by the vacuum.  A large leak can be audible from a couple hundred yard away.  A pinhole leak, just a few feet away, can initially sound nearly the same.  So can the rustling of desiccated Beech leaves, still attach to branches and rustling in the breeze.  Falls Brook, when it’s really running, casts a blanket of white noise over all lesser noises.

By the time I reached the Morningside 5 (M5) main line, one of the highest lines in the Nebraska Knoll bush, the din of Falls Brook had receded.  I heard a high-peaked twitter, then a dozen, then dozens, just up the hill to my left, then to my right, then all around me, as if listening to a flock of birds using headphones.  Full surround-sound for several minutes, as a flock of chickadees made its way along the hillside, alighting on ground or branches for a few seconds, then skipping ahead a tree or two.   The chatter subsided as the flock continued west.

A hour later, and quarter mile to the west, I was trudging up the Herbie 3 main line, alternating my attention between sap lines – looking for speeding air bubbles – and the uneven, saturated ground – hoping to avoid a season-ending knee twist or boot full of ice water.  At a moment when I was not pre-occupied by with avoiding mossy rocks and rain-filled vernal pools, a Barred Owl swooped in, and perched on a limb, high in the crown of a Beech tree twenty yards ahead of me.  Had I not seen it in flight, I would not have had a clue it was there.   It was there, I was sure, to see what I was doing.

But my bubble of self-importance burst when I noticed several small birds flitting through crowns of the trees around the owl.  It dawned on me: That flock of chickadees was of greater interest to the owl.  If I had heard the birds from fifty yards away, the owl likely heard them from the knoll above Keystone 5, half a mile across the valley, where I usually hear them.  But this raised many questions. 

Were the chickadees aware that the owl was among them? 
Do chickadees know that owls are predators? 
Were they not concerned for their safety? 
Or were they confident in their ability to evade an owl?  
Was the owl hoping a chickadee might land within reach of its talons?  
Does that actually happen?  

The owl moved on after a few minutes, in search of easier pickings.  And I resumed my rounds of Herbie with these questions to ponder, and some news from the bush to report back to the crew in the sugar house.

-LL

[Editor’s Note: The sap is still running. Today marked a turn toward warmer weather. Tomorrow will be the fifth consecutive day of boiling during what is clearly the closing chapter of Sugar Season 2022.]