Perplexing sky

 

Down here on the surface of the earth, we are used to judging distance with the help of contrast: distant objects have a lower contrast than those in the foreground. This insight works for solid objects with sharp boundaries. So, with each successively distant ridge, the trees lose contrast as dark objects become lighter and bright objects become darker.

This is so much a part of our experience that we don’t give it any thought while using it to judge relative distance. It is illustrated with a picture taken through the smoky air of last summer’s fire season (right), but the behaviour is the same, only more gradual, in clear air.

The guideline that contrast decreases with distance can be problematic when dealing with clouds, which range from the opaque to the diaphanous. Consider this morning’s sunrise shot. (The yellowish cast results from the smoke of forest fires farther east, and while the colour adds to the drama, it is not the point of this discussion.)

Rather, look at the contrail on the right side of the picture. We percieve it as being in front of the higher cloud because of its higher contrast. Alas, our perception is wrong. 

Consider the geometry of the scene. The sun is above the horizon and so must be shining down on all clouds. However, the contrail is casting a shadow on that supposed higher cloud. Ergo, despite perceptions, the contrail must be above (more distant than) the high cloud.

A contrail (right-hand side) looks as if it is lower than the high cloud, but it is actually higher.

 

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Horaltic vultures

 

If one wants to watch vultures, a good tactic is to hang out in the vicinity of carrion (sigh).

For most of us, finding carrion before a vulture does is not easy — except possibly during a seasonal die-off, such as what happens with spawning Kokanee. The carcasses of spent fish attract bears and birds for weeks on end.

However, merely spotting vultures does not guarantee that they will be seen in their horaltic pose, and that is what I set out to see. The horaltic pose of vultures (and a very few other large birds) involves perching in the sunlight with spectacularly spread wings. There are questions about this pose, none of which is easy to answer.

• Why do vultures do this?  Speculations are that the pose might facilitate: drying the wings, raising the temperature of the bird after a cold night, baking parasites. At one time or another, the purpose probably involves any of the three reasons.

• Why is the pose given the odd designaton, horaltic? The etymology of the name is obscure, although I suspect that it refers to the Egyptian god, Horus, which is sometimes represented by spread wings.

• Why did I want to see it? Well, it is an unusual pose for any bird and a spectacular one at that. It is certainly worth seeing.

I finally learned when and where to look in the trees above a local spawning creek.

A hint as to forthcoming vulture scavenging is the sighting of a kettle of vultures.

The dorsal surface of the Turkey Vulture looks black from a distance, but is actually a deep brown. Along with that, the adult vulture’s head is red and its hooked bill is ivory.

The underside of the vulture’s flight feathers are light, making the ventral surface two toned. 

A Turkey Vulture strikes a horaltic pose as it rests on the branch of a red cedar. It is early morning, and this pose seems to be struck to warm the bird with the first rays of sunlight following a cool night.

Sometimes the brownish dorsal surface of the wings is exposed, sometimes the two-toned ventral surface is exposed.

Here a juvenile vulture (grey head) warms its dorsal surface, while an adult (red head) exposes its ventral surface in a somewhat different stance. The adult’s pose is reminiscent of that of a heron, which sometimes uses this stance to raise wing temperature so as to allow sunlight to kill its parasites. Indeed, the adult vulture on the right was seen to be picking things out of its feathers.

An adult Turkey Vulture faces the sun and adopts a pose apparently used to cook its parasites. 

 

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Osprey harassed

 

This has been a really good year for wasps — not so good for the rest of us. Ospreys feed on fish, and wasps really like that.

An osprey has taken a fresh fish to the top of a piling to devour. However, wasps quickly gather around, behind, and on the fish. A bite into the fish holds the risk of downing an angry wasp.

Frustrated, the osprey vents. (OK, it was probably just lightening the load before takeoff, but it is pleasant to imagine that the wasps were being targeted.)

“I’m outa here, and you guys just cannot keep up with me.” 

 

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Young bucks

 

I am so used to seeing white-tailed does and fawns, that seeing a buck is unexpected — let alone three of them. But, there they were along the water’s edge.

The buck in the front is the only one still in velvet. But, the rather sparse growth of the antlers of the two behind suggests that they may be in their first-year as adults. Can anyone tell?

A close shot of a Janus buck gives a comparison between antlers in velvet (left) and those without.

 

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Ecotone walk

 

I could have merely spoken of a walk along the beach, but, I wanted to emphasize something subtly different than such a stroll.

An ecotone is a place where ecologies are in tension (in Greek, the word is tonos). It describes the boundary between two communities of plants or animals with differing characteristics. The ecotone is where the disparate communities meet, allowing an ecotone walker to witness the variety that comes with different wildlife communities. In particular, a beach walk can enable wildlife sightings of creatures that favour the lake, the shoreline transition, adjacent grasslands, and even the forest. The creatures shown, all seen this last week, are but a sample of the rich life to be seen on such a walk.

First, a view over the water.

The osprey and its captive Kokanee are both endemic to the lake. 

 

Then there are the creatures of the ecotone, those that live and hunt in the boundary between water and land.

A Lesser Yellowlegs Sandpiper grabs arthropods from the shallows along the shore.

A killdeer hunts along the shore side of the water’s edge.

A Northern Rough-winged Swallow forages for insects on the wing, sometimes doing so over the water and sometimes over the adjacent land.

 

One can also see creatures that specialize in the land side of the ecotone.

The Cooper’s Hawk is a forest raptor that eats small birds. Here it is hunting in the grasslands between the water and the forest. 

And a peek into the forest reveals the dark eyes of a fawn looking back.

 

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Iconic osprey shot

 

The West Arm of Kootenay Lake has an unusually large warm-season population of ospreys. As such, they have become a symbol of the Lake, with both a ferry and a community foundation named after them.

Ospreys feast on fish caught live. But, just try to capture a picture of an osprey lifting a fish from the Lake. The problem is that it happens amazingly quickly somewhere over a rather large area.  I have only managed to record the event once before.

Consequently, this morning’s shot of a (male) osprey lifting a (male) Kokanee from the Lake is one of my most satisfying shots of the year.

An Osprey and its catch.

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Fledged osprey

 

It seems maybe a week early, but juvenile ospreys have started to fledge.

A juvenile osprey — identified by wing feathers looking as if dipped in cream — flew by early this morning.

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Juvenile heron

 

This is the time to see juvenile birds. Although as large as adults, they often look somewhat different.

Today, I saw a juvenile Great Blue Heron standing on a deadhead. The signs were clear that it was this year’s chick. 

This Great Blue Heron hatched this summer. It lacks: the pigtail on the back of its head, a white crown, long shaggy neck feathers. And it has a well developed yellow patch in front of its eye.

This is the same bird flying off. Yet, its colour seems different. The hues here are closer to what would be considered correct for the bird. The previous shot was strongly influenced by yellowish light transmitted through a pall of smoke from distant forest fires. 

 

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Baird’s migration

 

The migration of shorebirds is underway. We have seen the killdeer pass through, however, the killdeer also breeds here. Not so, the Baird’s Sandpiper. It breeds in the high arctic and winters in South America. Baird’s visit to the Lake is brief.

A Baird’s Sandpiper flies to the shore of Kootenay Lake during its migration south. 

Its first act was to bathe and preen.

Then it is time to eat. It seems to have found a yummy dragonfly nymph.

 

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Killdeer migration

 

First there was one killdeer, then two, finally there were five of them.

These killdeers were on the move, probably merely stopping here for refuelling as they migrated from farther north to farther south. While killdeers breed locally, this group was probably just passing through — part of the annual migration of shorebirds.

A lone killdeer was spotted along the shore.

Soon more were seen, but never clustered tightly enough for a good group picture.

They fed. This one seems to have found a caddisfly larva. It was quickly downed.

Looking one’s best.

 

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