Two-grouse day

 

Yesterday, my backyard thermometer rose to +5° C for the first time in over a month. And with the warmth, Ruffed Grouse reappeared — two of them seen over 3 km apart.

The first grouse sat motionless in the bush and appeared to be a log butt showing its grain.

The second grouse didn’t feel any need to hide. It brazenly crossed my path confident that its plumage offered camouflage even in snow. It seems destined to make some coyote very happy.

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Accipiter

 

Fresh from having seen Trumpeter Swans in Kokanee Creek Park, I have now seen an accipiter there. 

Accipiters are a genus of hawks; They are not a species. Accipiters are distinguished by short, broad wings which have been adapted for fast flight through woods. As such, accipiters would seem to be a comfortable fit to our highly wooded Park.

But, which accipiter did I see? The picture, below, suggests two likely choices: Cooper’s Hawk, Sharp-shinned Hawk. At first I guessed one, but then decided from the picture that it was probably the other. 

However, rather than influence the few hard-core birders who subscribe to my blog, I leave it to them to tell me what it was that I saw in the Park.

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Trumpeters

 

Sometimes, persistence pays. Four days ago, I watched two swans circle over the bay to the west of Kokanee Creek Park. The next day I head reports of them, but failed to find them — they were in the vicinity, but where?

Today, I was looking for something else when friends said, “There are two swans at the bottom of this path….” Finally, I managed a shot.

However, there was a striking feature I had seen before: geese and dabbling ducks were keeping company with the swans. I suspect that their motivations had to do with the long necks of swans. All of these bird forage in the shallows by tipping down and using their long necks to scour the bottom. The longest necks belong to swans; they are able to forage to depths where geese and ducks cannot. But, if swans are present to stir up detritus on the bottom, geese and dabbling ducks can pick it off as it floats near the surface. So, it is that others like to hang out with swans.

Trumpeter Swans forage and attract Canada Geese and Mallards that take advantage of the activities. 

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Season of devils

 

For everything there is a season, and
a time for every matter under heaven:
a time to be born, and a time to die….

                                Ecclesiastes, chap. 3

To which a naturalist might add:

a time for rainbows, and a time for steam devils….

In the perceptive passage from Ecclesiastes, the teacher addresses episodic events in the lives of humans. Yet, the insight, that for everything there is a season, applies equally to the natural world. Normally, one does not look for rainbows in winter, nor for steam devils in summer. The study of quasiperiodicity in nature is phenology. While not as poetic as the teacher’s words, each speaks to nature’s seasonality.

What the devil? 
Dust devils, snow devils, and steam devils are whirlwinds close to the surface. Why this name? Devil is from a Greek root meaning to throw. Satan earned it by throwing slander. Dust devils earned it by throwing dust.

With the arrival of cold, I knew the season was here for steam devils over the Lake. The devils playing on the water this year have not yet been quite as spectacular as ones I have seen during previous cold snaps, see steam devils, and devils’ playground. However, until it gets really cold again, these are the best I have. 

To be able to see a steam devil, there has to be steam fog to serve as a tracer. With biting cold air flowing over the open waters of the Lake, convective sprites of steam fog abound. Occasionally, convection stretched a velocity gradient into a tall vortex and so created a steam devil. One appears in the foreground of this picture.

A very much taller but fainter steam devil appears in the distance. It probably would not have been noticed had it not been seen against the dark mountainside.

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Soffit pecking

 

It is a mystery: Why are woodpeckers attacking the soffits of my home now that it is cold out?

About the only time I had previously seen woodpeckers attack my home was in the spring when male Northern Flickers hammer on the metal flange of the chimney. They have discovered that thin metal provides a more impressive sound than does a tree and so more effectively demonstrate prowess to a potential mate. 

Yet, a couple of weeks ago, a Pileated Woodpecker made a racket as it probed under the chimney’s flange. As it was making a clatter at my chimney on Christmas morning, and as it wore a red cap, I succumbed to the temptation to suggest this was actually Santa Claus

I thought nothing more of it. But then, a male Pileated Woodpecker returned and probed a soffit for comestibles. A few hours later a Northern Flicker did likewise. After years of not bothering to look for arthropods in my siding, why were woodpeckers suddenly taking an interest in the house?

Throughout this period, it has been cold. Woodpeckers have probed trees, pilings, and utility poles during other winters, but what is it about the wooden siding of a house that attracts them now? I don’t know.

A Pileated Woodpecker probes for grubs along the soffit of my home.

A few hours later, a Northern Flicker does likewise.

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Bobcat

 

As a portrait of a bobcat, this is mediocre. However, as it is the first bobcat I have photographed, it is a winner for me. 

The bobcat was on a path on the west side of Kokanee Creek. It paused to look at me but then continued on its way across a footbridge, clearly appreciating the effort humans put into supplying it with a convenient path through the wilderness. 

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Orange in winter

 

I went birding today — well animal-ing, for I also saw an otter. While I photographed many species of birds, it wasn’t until I returned to the comfort of my home that I managed a good shot, and that was taken — gulp — looking through a window. 

The Varied Thrush is a skittish bird. While it is related to the robin, it lacks the robin’s sangfroid and will bolt at the slightest perceived threat, which it interprets as the sight of anything at all. Consequently, the best pictures of it I have ever managed have been taken using my home or car as a blind.

The Varied Thrush, a striking bird in black and orange, is a contrast to our monochromatic winter.

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Hoodie affection

 

A pair of Hooded Mergansers on the Lake this morning unexpectedly raised their crests. It seems a few months too early for such courting behaviour.

Are Hooded Mergansers courting in December?

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Santa Claus

 

When out on the roof there arose such a clatter,
I sprang from my bed to see what was the matter.

Just as the poem says, early this Christmas morning I really did hear a clatter on my roof and I sprang from my chair to see what was the matter.

There he was on my chimney, replete with a white-trimmed red cap. I’m not making this up — I took a picture. 

The truth is out: Santa Claus is a Pileated Woodpecker.

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Green ice

 

And now there came both mist and snow,
And it grew wondrous cold:
And ice, mast-high, came floating by,
As green as emerald.
           Samuel Taylor Coleridge  (1798)
           The Rime of the Ancient Mariner

Green ice holds an almost mystical status among aficionados of cold. Coleridge mentions green icebergs in 1798, and there have been a handful of similar observations through subsequent centuries.

Although green ice is uncommon, it can be seen locally, not in icebergs, but in anchor ice.

The recent cold snap brought anchor ice to local creeks. I offered an explanation of how ice forms on the creek bed three years ago, so that need not be repeated here. However, an explanation seems in order for the fact that on both occasions the ice on the stream bed appeared jade.

How can ice be green? The explanation offered below involves two processes: one that primarily absorbs light at the reddish end of the visible spectrum; the other that primarily absorbs light at the blueish end. What remains is light from near the spectral middle: green.

Specious guesswork 
It is worth dismissing the standard glib suggestion that such an unusual colour arises from embedded impurities. All the water from which this ice formed is remarkably clean and free of sediments and biota (it is winter). The colour seen is a characteristic of the ice and lighting, not suspended dirt.

Facts
Begin with what is known: both water and ice are intrinsically blue. This might seem at variance with common experiences of seeing a glass of water or an ice cube, but each has a rather small volume. To see the blue, a light absorption path of metres (not centimetres) is needed. Look down a deep hole punched in snow. It is blue, as is the light in an ice cave or that which reaches the bottom of a lake. (Of course, the light seen when looking down on top of a lake or glacier is complicated by surface reflections.) When visible light passes through water or ice the greatest absorption is at the red end of the spectrum. There is a progressive decline in absorption through the orange, yellow and green with the least absorption being at the blue end. Energy remains throughout the spectrum, but the eye perceives the composite as blue. 

Anchor ice is resting on an ochre stream bed (2013).

Path-length problem
Leaving aside that the aim is to explain green, not blue, it would seem that the anchor ice in the picture below is too thin to give the long absorption path needed for seeing colour. However, anchor ice is rather porous (see previous explanation), having many internal surfaces between ice and water that scatter the light to and fro as if in a pinball machine. So, light travels a tortuous path that is vastly greater than the ice thickness and certainly sufficient to give the transmitted light a bluish cast.

Ochre stream bed 
The bluish light that passes through the anchor ice reaches a characteristically earthy coloured stream bed. While absorption in the ice largely removed the reddish end of the spectrum, absorption by the stream bed now largely removes the bluish end of the spectrum. The dominant light that re-emerges from the ice is in the relatively undiminished middle of the spectrum: green.

Last Saturday at the height of the cold snap, anchor ice offered the best local example of green ice.

 

Green icebergs
Offered was a plausible explanation of the green of anchor ice. However, is it in any way applicable to the icebergs described by Coleridge and others? Yes, somewhat. What was apparent with the anchor ice was that it involved two counteracting processes: ice that absorbed the reddish end of the spectrum and something else that depleted the bluish end. With anchor ice, that something else was absorption by the ochre stream bed. For green icebergs, this is replaced by atmospheric scattering that reddens the illumination from the low polar Sun. The result is much the same: green ice.

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