Holes in a cloud

Posted on October 20, 2018 by Alistair

 

A week ago, I showed iridescence in a lenticular cloud (colours in a wave cloud). Here is another uncommon feature of such clouds: lacunosus, that is, the cloud is potmarked with holes. (Lacunosus is Latin for: full of lacunae, that is holes.)

The holes are caused by convective bubbles of warm air from the clear air below the cloud that then rise through it and punch holes in it. Normally this wouldn’t happen as the temperature of the clear air below the cloud is about the same as that in the cloud. However, the cloud sits at the crest of a wave in the atmosphere that resulted from the air flowing over a mountain, and sometimes the wave begins to collapse. This causes the cloud and surrounding air to descend. 

Now, an odd thing happens. As air descends, it is compressed by the higher pressure it encounters at a lower elevations. The air temperature rises as a result of this compression. Interestingly, the temperature rise in the clear air above and below the cloud is greater than that in the cloud, with the result that the warmer lower air rises in little bubbles and punches holes in the cloud.

A collapsing mountain wave produces lacunosus in the lenticular cloud.

 

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Spoonbill Crow

Posted on October 18, 2018 by Alistair

 

Spoonbills are a genus of large wading birds with spoon-shaped bills. Alas, none of the species are found around the Lake. 

What we do have is a spoonbill in morphology, if not in name: the Northern Shoveler. 

Yet, I have just photographed another one: the exceedingly rare Spoonbill Crow.

A flock of Northern Shovelers display their spoon-shaped bills.

Today, the exceedingly rare Spoonbill Crow flew past me. (Sorry, I couldn’t help myself.)

 

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Woodpecker’s home probe

Posted on October 17, 2018 by Alistair

 

For three days, a Pileated Woodpecker has been probing the outside of my house for comestibles. I don’t think that the bird discovers much, but it is welcome to anything it finds.

A female Pileated Woodpecker checks for bugs around the edges of a triangular window.

Not finding much around the window, it uses its tongue to probe a crack in the trim.

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Merganser liftoff

Posted on October 16, 2018 by Alistair

 

What is the point of this morning’s picture? After all, a Common Merganser (this is a juvenile) lifts off from water a myriad times a day.

I just found the image pleasing.

 

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Rusty Blackbird

Posted on October 15, 2018 by Alistair

 

The Rusty Blackbird is an infrequent visitor to the Lake. Indeed, most posted range maps suggest that it is not to be seen here at all. Yet, here it was on its fall migration foraging, apparently for arthropods, in ponds beside the Lake. (I would have missed the little flock had it not been for a chance encounter with Janice Arndt, who suggested what I could see if I were to head down a alternative path.) 

A few of the Rusty Blackbirds scouring the edge of a pond for delectables.

The birds would scour one small area and then fly to the next.

This is perhaps my favourite shot of the event. Two Rusty Blackbirds search the pond for arthropods, and one has been found. But, look at the autumnal colours reflected in the water.

This bird begins to pick up another arthropod that it had already turned over.

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Cloud colours

Posted on October 12, 2018 by Alistair

 

The spectacular colours of fall are naturally associated with deciduous trees. Yet, these are not the only delightful variegation to be seen. Iridescent clouds are often visible in this season.

The colours in iridescent clouds arise from the interference experienced by light as it passes uniformly sized water drops, usually those found in lenticular clouds. The dominant cloud of summer, the cumulus, has a large diversity of droplet sizes with the result that iridescence is not seen. With the arrival of the colder months, the winds aloft strengthen and mountain waves form giving rise to frequent lenticular clouds. Of course, lenticular clouds are common in the winter also, but, for those of us beset with valley stratus, the view is blocked. So, for valley dwellers, the fall is a good time to see the brilliant colours of iridescent clouds.

Brilliant is the key word here. The colours form close to the sun where the light’s intensity is dazzling. Find a lenticular cloud adjacent to or covering the sun. Block out the sun and use sunglasses. (Stop your camera down by about three stops from the automatic reading.) The rewards are as grand as seeing a mountainside of larches. Below are two pictures taken yesterday.

 

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Sniper

Posted on October 11, 2018 by Alistair

 

When spooked, a snipe bolts from its hiding place at a great speed and is gone. Consequently, shooting a flying snipe presents a considerable challenge. So much so, that those who became good at it were called snipers — a term that was adopted by the military for a marksman.

In late summer, I spooked a snipe, but it vanished in a blur before I could shoot its picture. Yesterday, a snipe erupted along my path; I shot it. I now qualify as a sniper.

A Wilson’s Snipe bolts.

 

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Pika predator

Posted on October 8, 2018 by Alistair

 

The pika is generally acknowledged as an adorable creature. Beyond its native cuteness, it is a herbivore and so is appealing because it feeds on nothing but plants.

Yesterday, I revisited the pika colony discussed earlier. Snow had fallen and the pikas obviously struggled with snow having cut off access to food.

Yet, a much greater threat than a seasonal change beset them. They had to face a new, and effective, predator: a long-tailed weasel. 

A pika forages for vegetative delectables in the snow.

A long-tailed weasel moved into the pika colony. Its slim body enabled it to enter the cavities between the rocks where pikas lived.

The weasel arrived and began to prowl for comestibles.

“Why are you terrorizing us? We have done you no harm.”

“I am unconcerned with whether you are nurturing, only that you are nutritious.”

 

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Pikas prepare

Posted on October 4, 2018 by Alistair

 

Pikas do not hibernate, so during the summer, they collect and store food for the winter. As winter approaches, preparation becomes intense. These pictures were taken two days ago. Yesterday, snow fell on the pikas. 

Dyslexia: Pikas normally live in talus, but these ones live in tailings. Are pikas dyslexic? Chuckle.

This was a large colony of pikas, with frenetic activity on every side.

A pika announces interlopers with an “EEP”. However, all quickly returned to foraging.

A pika forages vegetation beside the rocks.

And carries it back to its lair for the winter.

Some leaves are consumed on the spot.

As are stalks.

“Looking good in my winter pelage.”

 

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Mystery bird

Posted on October 1, 2018 by Alistair

 

Is the identity of this bird actually a mystery? Well, I know what it is.

However, the Sybley Guide to Birds offered no guidance. And, Cornell’s Merlin Bird ID (an avian-recognition app) made a number of guesses, all of which were wrong.

So, I thought that others might enjoy the challenge of identifying this large brownish bird.

What is this late-summer bird?

 

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