Species diversity

 

A year ago on Canada Day, I posted a collection of my favourite images from the previous decade, and said: “My two-dozen mute portraits offer peeks into the charm and beauty of life in Canada.” Commenting on it, Carlo said that it offered a “somewhat different view of our ‘population diversity’ than what is usually presented.” I liked that.

So, on a day when most people choose to celebrate themselves, I will celebrate a broader diversity with a collection of my favourite images recorded since last year’s July 1st. Some are permanent residents and some are migrants. (Note: No migrant was apprehended, harmed, or separated during these encounters.) 

A Black Bear cub catches its first Kokanee salmon in a local creek.

A Northern Flicker chick welcomes its mummy bringing food. 

A Mountain Bluebird dons a tutu.

A Grizzly Bear sow and her cub graze in a field.

A Golden Eagle scours the valley bottom for comestibles.

Snowshoe Hares were plentiful this last year.

A Great Blue Heron flies overhead.

Looking out from treeline talus, a Hoary Marmot guards his domain.

A Hooded Merganser swallows a sucker whole.

A Mallard demonstrates walking on water.

An Osprey flies by with a headless fish.

The Mule Deer is the only local animal that stots.

Two River Otters claim a dock as now belonging to them.

A Pika cries “eep”.

Common Redpolls scrounge seeds in the midwinter.

A male Ruffed Grouse is in full display.

A Red-winged Blackbird announces springtime.

This Wood Duck is confident that it is superior to all the rest of us.

 

Posted in birds, commentary, mammals | 15 Comments

June goulash

 

This a collection of June images, none of which has had a posting of its own.

A female Common Yellowthroat watches for insects to eat.
A male Common Yellowthroat has managed to catch a bug to eat.

Two Yellow-bellied Marmots enjoy a friendly tussle.

A female Goldeneye rises from out of the water.

An osprey and her chick look out of a massive nest.

A Pacific-slope Flycatcher incubates her eggs in a tiny nest.

A female Black-headed Grosbeak hunts for insects — she was a grand sight.

A White-tailed buck, with starter antlers, hunts for comestibles in a field.

Finally, a panorama from the side of Morning Mountain. On the right is Nelson, the West Arm of Kootenay Lake, and beyond them, the snow-covered mountains of Kokanee Glacier Provincial Park. In the centre is Grohman Creek and (on the ridge) the Baldface Ski Resort. The mountains of Valhalla Provincial Park are on the far left.
Move the cursor to (mobile: tap image at) various places across the frame to see it all.

 

Posted in birds, mammals, scenes | 1 Comment

Fat and yellow

 

As far as I can tell, the daisy is the favourite local hunting ground of crab spiders (Misumena vatia), so when the daisies bloom, I scan them for spiders.

The crab spider is a chameleon: it can change colour so as to match its background, and so be unnoticed by the pollinators it would capture and eat. It has two colours: white is its base colour, but by secreting a yellow pigment into the outer cellular layer of the body, it can turn yellow. 

A white and yellow flower, such as a daisy, is thus ideal. When it hunts from the petals, it is white; when it hunts from the floral disc (centre), it is yellow. Yet, I have almost always seen it white and hunting from the petals — only rarely is it yellow and hunting from the disc. The spider has a distinct bias toward white. 

A white crab spider hunts from the petals of a daisy (2013).

Is this because there is a greater area of petals, or perhaps because it hunts from the sidelines when pollinators head for the floral disc? Possibly both, but there is another possibility: it is not easy to turn yellow. It takes the spider about 6 days to change from yellow to white, but from 10 to 25 days to turn from white to yellow. Producing and infusing its skin with the yellow pigment seems to be hard work. Maybe the crab spider would just rather not put in the effort.

Now, if you start searching daisies for crab spiders, you will probably find that you have to check a few hundred before spotting one — and that spider will be white. I don’t know what the incidence of yellow crab spiders on daisies is, but it is perhaps only one in a few thousand. However, once you find a crab spider on a flower, you can return day after day, and it will still be there.

In a somewhat uncommon sight, a rather fat and yellow, female, crab spider hunts from a daisy. She clearly has been gorging on pollinators. Given her stance, she looks almost as if she is prepared to defend her daisy from the photographer.

 

Posted in bugs | 4 Comments

Problem hawk

 

Sometimes I just don’t know what it is I am looking at. 

Consider this hawk seen this morning: what is it?

Suggestions are welcome.

 

Posted in birds | 5 Comments

Dew, not dew

 

The web of an orb-weaving spider covered in matutinal drops of water is undoubtedly beautiful. But, is the web really covered in dew — as is claimed by a myriad of photo sites? Alas, this is something for which reason is unlikely to overcome glibness. After all, what could be more obvious: of course those droplets are dew — right?

Dew is not a generic name for water drops that appear early in the day. Actually, a number of processes can cause such drops: along with dew are drizzle, rain, guttation, and the collection of fog drops. 

Dew results from temperature differences that increase with object size
When an object has a temperature lower than the dew-point temperature of the surrounding air, dew will form on it. A net loss of infrared radiation to the sky will drop an object’s temperature, but thermal conduction from the surrounding warmer air will counteract this. For a tiny object (a spider’s thread), conduction keeps the object at the same temperature as the air, and dew won’t form. For a larger object (a flower) the radiation loss will probably win, and dew will form.

Collection of fog drops is greatest with tiny objects
Yet, droplets sometimes appear on a spider’s web. As they don’t result from dew, how do they form? This is a question of how air flows around and past objects. A small object (spider’s thread) does not deviate airflow significantly, so drifting fog droplets just collide with, and are collected by, the object. A larger object (daisy) causes the air to flow around it, and this carries fog droplets around and past it, so their intersection is minimal.

Dew has formed on the sky-facing petals of this daisy. Net infrared radiation loss caused the petals to cool and dew to form. The flower is large enough to be able to sustain a temperature difference between itself and the surrounding air, so dew can form. (The daisy’s stem was protected by the flower from such radiation losses to the sky and so shows no dew.)

It is tempting to think that the same process of dew formation would have caused the formation of droplets on the spider’s web. Yet, the spider threads are so fine that thermal conduction guarantees that they will have the same temperature as the air. So, dew cannot form here. Yet, the tiny threads of the web intersect some of the drops of a steam fog drifting past. (A larger object would merely cause the airflow to be deviated and the drops to flow around them.) The result is that small objects (such as spider threads) intersect passing fog drops, but haven’t sustained the temperature difference that results in dew. Larger objects (such as the daisy) have a dew-producing temperature difference, but don’t intersect fog drops.

Once, while mentioning this behavioural difference during a presentation, I was asked why the drops on the spider’s web were often uniform in size and spacing (as shown in this older picture), despite having resulted from random impacts of fog droplets. I didn’t know the answer. But it turns out that it has to do with regularly spaced sticky balls of glue the spider attaches to the spiral threads so as to trap flying insects. These glue drops absorb the collected water drops and swell producing the both the regularity and the difference between the drops on the spiral and radial threads.

 

Posted in bugs, weather, wildflowers | 7 Comments

Amplexus consequences

 

One month after taking pictures of Western Toads in amplexus, I returned to the same shoreline. The consequence of the earlier activity was impressive: thousands of tadpoles.

 

Posted in herptiles | 2 Comments

Pika cries “eep!”

 

Pikas live in talus, usually near the treeline.

The talus visited two days ago was near neither road nor trail. The pikas that lived there would likely be unfamiliar with humans, as even access from below was impeded by a bog.

However, a pika saw a human that day, and after consideration, it issued an alarm of “eep”. Consequently, all the pikas vanished into the talus. But, for how long?

A pika is a herbivore that is hunted by coyotes, bobcats, weasels, and raptors, none of which look or move like a lumbering human. Is this new interloper a predator? This pika was low on the talus, seemingly positioned to guard the approach. To assess the danger, the pika popped up at various places around the interloper. As the pika is prey, it has eyes on the sides of its head to give it a wide field of view. It is watching sideways. 

The pika took its time before adopting the route of caution. Here it is facing its colleagues on the upper portion of the talus and crying, “eep”. It and all other pikas then vanished among the rocks.

Nothing stirred for about twenty minutes, but then, assuming that danger had passed, a few pikas emerged and began foraging among the rocks for lichen. 

Some adventurous ones even left the talus to forage for greens on adjacent slopes. Despite their rather large ears, these pikas did not seem aware of the incessant camera clicks.

“Eep, I told you, eep! Do you want to end up being gawked at on someone’s blog? Shame on you!”

 

Posted in mammals | 4 Comments

Headless fish flying

 

Unexpectedly, many of the fish flying around our skies are headless.

That fish fly is courtesy of the good graces of ospreys. Yet, it is striking that many of these flying fish lack a head. After catching a fish, an osprey often will stop somewhere and devour the head (brains are tasty) before carrying the rest of it back to the nest.

A female Osprey packs a headless fish (a sucker).

 

Posted in birds, fish | 1 Comment

Caught mid-gronk

 

The Great Blue Heron is fairly visible — yet it is listed as locally vulnerable. It is almost always silent — yet it was photographed mid-gronk.

In one’s imagination, the raspy gronk of the heron is atavistic: the call of the pterodactyl.

The Great Blue Heron gronks as it flies past.

 

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Kisses

 

Marmots are playful and affectionate.

We have two species around the Lake: the smaller, Yellow-bellied Marmots, live in the valleys; the larger, Hoary Marmots, live high in the mountains.

These Hoary Marmots were seen at about 1600 metres elevation. The mating period is likely over, and the juveniles are not yet out, so these are probably merely friendly adults.

“Let’s fool around.”

“Shall we dance?”

“Why not just make out?”

Smack!

“And another one.” 

“Don’t mind me, I just like to watch.” 

Posted in mammals | 3 Comments