Saturday, February 22, 2014

Not "Wild" wild, but very pretty!

D. W. Field Park spans a large north-south area around Brockton's northern border.

I haven't walked in D.W. FieldPark in a long time--shocking, considering how close I live to the Jewel of the city.  Today is incredibly warm and sunny, and my youngest son and I took the dogs there as an excuse to visit.

The park is paved in loops with lanes for both driving and pedestrians.

A low hill makes a perfect vantage.

The park is arranged around a series of ponds.

Stephen has both dogs so I can take a photo.

Golda and Linkin had a ball, except that every other dog owner in the city seemed to be there.
(Seeing another dog, Linkin especially becomes a dogicidal maniac.)

Park benches make nice places for contemplating the landscape.

A "lantern tree" (American beech).

I've been putting down D.W. FieldPark as I've lately emphasized Wild Places, forgetting how beautiful it is.  Although a designed landscape (inspired by Frederick Law Olmsted) which may be heading for a makeover, I would now call it fairly "naturalized," though of course it is still managed--witness the obvious black top, and slightly subtler marks of the chainsaw.

On the other hand, I am considering managing my own little Wild Place come spring, tearing out as much of the invasive English ivy, vinca, and European buckthorn as I can, along with a few of the smaller Norway maples (also invasive); and planting a few native trees like white pine.  I will be trading a bit of land compromised in one way, with land compromised in another, more tolerable, way.  Less wild, more "wilderness."

Tuesday, February 18, 2014

Birds at My Feeder; a Sundog

A new bird at my feeder this morning as I poured my first cup: white with a blue-gray back, dark atop the head but otherwise white face with a long needle-like bill.  A few minutes with my Sibley Field Guide confirmed a white-breasted nuthatch.  They're supposed to be common, but I hadn't seen one before--certainly never at my feeder.  My feeder is patronized mostly by mobs of house sparrows (alien city birds), but has gradually attracted a little variety of birds: lots of slate-colored juncos, some tufted titmice and black-capped chickadees, and the occasional house finch and cardinal.  Odd how the house finch once very common at my feeders could become so rare.

More snow today, turning to freezing rain before ending.

© Mike E. Worthington, Georgia, January 2009

female & male house sparrows (

Dark-eyed junco (slate-colored)
© Michael Hogan, New Jersey, February 2004

House finch © Jeff Hurd

The link below reminded me of an experience a week ago.  I was in Rhode Island, driving my mother to visit my father in the nursing home, when I noticed that the sun, dimmed by clouds, was reddish on one side, bluish on the other.  I brought it to her attention, and it was clear enough that my mother was able to make it out despite serious vision trouble, and we admired it for some while.  Only after several minutes did I spot the real sun--much brighter--some distance away (earlier masked by buildings).  I guessed that, like a rainbow, it was caused by some sort of refraction by water in the air, but had no idea of the details.  Here is a very nice sundog, how they form, and what happened to it when a spacecraft was launched nearby.

Wednesday, February 5, 2014

No, the Universe Doesn't Hate Us (a little Snow Physics)

My wife called it, rather pointedly, heart attack snow.  It would be heavy and wet and accumulate all day.  Better to shovel several times--not letting it get too deep--than try to clear the driveway all at once at the end. 

So I reminded my wife that the issue is power, not energy.  It takes a certain amount of energy to clear the driveway, and the total amount of energy won't vary too much whether the driveway is cleared in stages, or all at the end.*  (I suppose most of that energy goes into lifting the snow against gravity, though some part goes into throwing it varying distances.)   The demand shoveling snow puts on your cardiovascular system is a matter of power.  Power is energy per unit time.  Any number of units could be used; I like Joules/second, which is the fundamental metric unit, but if you're interested in your use of food energy, or losing weight, you might use, say, Calories/minute. 

Let's imagine that clearing the entire driveway of six inches of  heavy, wet snow requires expending 500 Calories.  You could take it easy, take small bites with your shovel, do it over the course of two hours (don't forget to take breaks!) and exert an average power of 500 Calories/2 hours = 250 Cal/h.  Or you could do a rush job, finishing in one hour, and exert 500 Cal/h -- twice the power does the same job in half the time.  The oxygen to burn those calories (and the carbon dioxide that results) is delivered by your hard-working lungs, heart and blood vessels.  If you don't get much aerobic exercise between snowfalls, I'd recommend option A!  (Or take my wife's advice; or get a snow thrower.) 

You see the distinction between energy and power all the time once you become familiar with it.  It is the reason that my little Hyundai and a Porsche can both drive the speed limit on the highway--but the Porsche can get to that speed from the on-ramp a LOT quicker than I can!  It is also the reason my old dad can still climb the stairs in his house with his failing heart, but he has to take them more slowly than I do.

Now to the main question.  If you live in a snowier clime, you will have noticed that more snow falls where you have just shoveled than in the surrounding areas.  The effect is most noticeable at the edges.  In other words, when it comes to show shoveling the universe seems to punish virtue!  But I'm pretty sure the universe (Splendid though it is) doesn't care about us much one way or the other, and certain it doesn't care that--much less how--we shovel.  What's going on, then?

As I reached the bottom of the driveway on Tuesday morning, a clue appeared in the snow that had accumulated between the cars.

Only five inches between the cars, but eight by
my little Hyundai and a foot by the minivan.

Here's the secret.  Moving fluid carries more and bigger particles the faster it is moving.  That's it.  The rule is usually applied to rivers, but it applies equally to snow-laden air.  Snow falls slowly, so that even a slight breeze will keep some of it suspended until the air slows down.  This is why snow forms drifts: the air slows when it meets an obstacle, and more snow is deposited. (The cars in the driveway are Big obstacles.)  It explains why the snow is deeper at the edges of the driveway (close to the high curb) than it is in the middle of the driveway.  It explains why I will shovel more snow if I shovel more times--each time I shovel, I am making a new "wind shadow" that will slow the air, depositing some of its white load.

This also one reason it is so difficult to measure snowfall: small variations in the landscape--as well as obvious barriers--can lead to different amounts of accumulation.

Another application of the principle explains a lot about rivers.  As the speed of moving water increases, it picks up more and bigger particles of sediment, as it slows it deposits them, beginning with the largest and heaviest.  The lower reaches of the Mississippi River, flowing over nearly level land, meanders because it does: any slight random bend in the river causes the water to slow a bit on the inside of the bend, and speed up on the outside.  Sediments are eroded by the faster moving water on the outside, forming a cut bank, while they are deposited on the inside, forming a point bar.  This makes the river bend greater and greater, as the river digs farther and farther into its outside edge.  In other words, a river meanders because it does! 

By the same token, it explains why the highest land in New Orleans is (against all "common sense") on the banks of the Mississippi River itself.  The land all around the river was created by the river overflowing its banks in periodic floods.  As the sediment-laden water leaves the fast-flowing channel it immediately slows, dropping most of its load.  The water that floods farther into the countryside has less sediment and gains less new land.  The historic French Quarter is right on the bank, while lower areas farther from the river weren't settled until this marshy land could be efficiently drained.  (It's a little jarring to realize that the surface of the river may actually be above your head as you stand only a short distance away.)  By the same token, the flooding of New Orleans after hurricane Katrina left the French Quarter nearly untouched, while it did the most damage to the poorest neighborhoods in these less-desirable lowlands. 

Only the green areas  are actually above sea level; the white are at, the yellow are below, sea level.  Note that the RIVER did not flood after Katrina; the water came from Lake Ponchartrain via the canals.

Since the river is now confined behind high levees where it cannot escape to spread its sediments, the situation of New Orleans must become fundamentally worse with time, as sediment-built land sinks and sea levels rise.

*Actually, it will, but in a way that favors doing it all at once.  And soon you will know why.

Tuesday, February 4, 2014

Happy 128th Birthday, Blue Hill Observatory!

Blue Hill Reservation.  Parking and visitor center on rt 138, 
top of Great Blue Hill shown by Summit Rd, which winds beside ski trails.

Went for a lazy Saturday late afternoon jaunt up Great Blue Hill with Stephen. The Trailside Museum at the bottom of the hill was open, and some of the animals were weathering the cold in their enclosures.  We spent a little time looking at the red-tailed hawk, turkey vulture and the pond full of mallards, but as always the river otter stole the show with his (her?) acrobatic swimming.  We had neither the time nor the money to go into the museum itself, but headed up the red dot trail.

It was a nice walk if hazardous (icy), with the bonus that we got into the Blue Hill Meteorological Observatory, which celebrated its 128th birthday on Jan 31.  The Blue Hill Observatory boasts the longest continuous weather record in the country.  We watched the Scouts of Troop 1 Acton fly kites, and then ventured in to see if we could look around.  We paid our $3.50 plus $1 for Stephen, and were pretty much left alone to explore.  My expression of surprise at finding a gift shop inside proved to our guide it had been at least a decade since last I'd visited.  We spent most of our time on the roof taking in the view.  I was surprised that it was difficult to spot the observation tower only a quarter-mile away, and someone had to point out the verdigris-coated peak of the tower roof, just peeking between tree crowns.  

Observatory nearing sunset in overcast.

Some of the instruments on the roof.  All of these measure wind speed and some also direction, 
except the spiky thing at farthest left--??

This thing is my personal favorite for cleverness: the glass globe sharply focuses sunlight to burn marks on the green card just visible inside the metal bowl; the resulting burn track as the sun crosses the sky makes a permanent  timed record of clear weather, since unburned portions result from interference by clouds.

View from the roof of the tower: Ponkapoag pond in the distance.

View from the roof of the tower.

Stephen thought this was a pretty cool place.  Just to the right of him is a lightning rod 
that goes to a heavy cable, thence down the outside of the tower to ground.

Stephen stands on the ice of a small pond beside Coon Hollow Path on the way down.

Blue Hill Observatory was founded by a young amateur meteorologist Abbott Lawrence Rotch, scion of an old and wealthy Boston family, who invested part of his inheritance to build it.  After Rotch's death of appendicitis in 1912, the Observatory was bequeathed, with an endowment, to Harvard University, which had it until 1971 when the Massachusetts Metropolitan District Commission (administrator of the Blue Hill Reservation in which it sits).  It has long been and continues to be a National Weather Service observing station, and involved in the American Meteorological Society.  Just before the turn of the present century, the Blue Hill Observatory Science Center wa founded, "expanding ever since its aim of "increasing public understanding of, and appreciation for, atmospheric science."  The Scouts of troop 1 Acton, at work on their meteorology merit badges, were witness to this new focus. 

Weekdays the Observatory is staffed by professional meteorologists, who spend their days recording instrument readings and performing complex calculations.  On weekends specially trained amateur observers take over. Most of the time volunteers are around to man the gift shop, lead tours and answer questions.  The volunteer I spoke with was completely familiar with station operations, and an enthusiastic teacher.   

The walk up Blue Hill to the tower and observatory is less than a mile uphill through forest over soil and rocks with no scrambling necessary, and takes less than half an hour.  Tours are 10am to 4pm on Saturdays year-round, and also on Sundays at this time of year.  Of course, the Blue Hill Reservation is much bigger and you can walk all day (or more) on well-marked paths without coming to the end of it.

Saturday, February 1, 2014

Enjoy! --But Don't Feed Them!

I  ventured out back yesterday morning looking for new tracks of our elusive coywolf (aka eastern coyote*), and found beautiful fresh tracks all over the place.  I planned to follow them later on to see what she'd been up to, but in the meantime, the dogs needed to go out.  I wondered what the dogs would think of fresh coyote tracks, so I brought them to see.  In the process, the three of us surprised Herself, who spotted us as I did her, about 30 yards away.  (The dogs, bless their weak eyesight, never saw her at all.)  She wheeled instantly round and trotted back into the woods at a pace efficient but not especially hurried.  The dogs, meanwhile, were fascinated by the tracks and snuffled them as thoroughly as my patience would permit.

Going out to take pictures shortly afterward, we surprised each other again.  --odd that she would have stayed so close.  Or maybe not...  Tavi, the little girl my wife looks after on most school mornings, wanted to see them, so I brought her out an hour later, only to surprise Herself a second time.  Tavi was delighted, and went to school with a story to tell. 

I conclude that my elusive coywolf isn't elusive at all, but very familiar--and maybe almost too friendly.  Certainly not the "catch" I pictured her as--a wild animal I once thought to spy on with a night-vision camera (actually a baby monitor picked up from a yard sale).  Instead, I expect to be on a first name basis very soon.

Coywolf in "The Beach" neighborhood of Toronto.  Photo credit copywrite 2013 Coy Wolf Inc., take from

I began looking up info on coywolves after happening upon a PBS Nature program, and finding out that these enormously adaptable animals are at home even in downtown urban areas--populations are under study in New York City and Toronto.  They are beautiful animals, coyote-like in shape, but closer to gray wolves in size.  Despite have no protection under the law, their populations are expanding in forty-nine states.  They appear to mate for life.  They eat enough rodents to help control populations, and are also very fond of eggs of Canada Geese, whose populations are out-of-control in these parts.  They sometimes tackle deer. 

Coywolves coexist quite happily with humans, liking the environment we create while remaining just skittish enough not to be often seen--especially considering their large populations.  A coywolf can have a territory of 6 square miles, but in a city needs only half that.  Although they sometimes eat pets, the danger of that is probably exaggerated; but best we don't leave pets outdoors unattended.  Statistically, they aren't nearly as dangerous to humans as dogs are. 

The biggest danger to us from these animals comes if they lose their fear of us.  History suggests that we can continue to live happily together if we humans follow one simple rule: DON'T FEED THEM.  It is regular feeding that brings them into frequent close contact and causes them to become fearless.  Therefore do not feed them deliberately, and also avoid feeding them even accidentally--such as by feeding pets outdoors. 

I hope to see them out my windows often.  They're beautiful animals.  But I hope never to see one stand his or her ground in my presence; that animal would sooner or later be a danger to the neighborhood pets and possibly people, and someday likely face a police bullet.

*Now established to be part of a widely-distributed population hybrid between the western coyote and the eastern wolf, with an interesting history.