Spider and fly

 

“Will you walk into my parlour?” said the Spider to the Fly.

And set his her table ready, to dine upon the Fly.

The text adapts Mary Howitt’s 1829 parable, The Spider and the Fly.

Posted in bugs | 2 Comments

Harrop

 

Another sunny day, another panorama from high on a Forest Service road. Previously a panorama was centred on Queen’s Bay. This view was taken a little to west and only shows a bit of the Main Lake and the Purcell Mountains on the left. Besides Harrop, on the far side of the West Arm, one can see the peninsula with Kokanee Creek Park on the far right. The Harrop cable ferry is crossing the Arm.

Move the cursor to (mobile: tap image at) various places across the frame to see the whole picture.

Posted in scenes | Leave a comment

Alulae or not

 

Alula: A structure on a bird’s wing occasionally deployed to limit stalling at high angles of attack.

It is fun to discover something on one’s own — even if it is already in the literature. Such was the case this morning while I watched a hummingbird: I realized it lacks alulae.

Most birds have and make good use of alulae. However, alulae are unseen when a bird isn’t flying and only momentarily seen when it is. Consequently, the lack of visible alulae would normally merely be a sign that they aren’t deployed, rather than that they don’t exist. Well, that is my excuse for having taking so long to realize that hummingbirds lack alulae.

Hummingbirds have a different style of flying than other birds. Most birds only obtain lift when their wings are extended during a downstroke, not when wings are somewhat folded during an upstroke. Hummingbird wings are extended during both downstroke and upstroke. During downstroke, most of the lift is obtained, but during upstroke lift is increased by a further third when wings are twisted. 

Most birds must have a rapid flow of air against sloping wings to stay airborne. But, when such a bird lands, it must slow. This requires an increase in the slope of the wings (the angle of attack) for it to remain airborne at the lower speed. However, this increases the likelihood of a stall. A solution to this problem is to deploy the alulae which force the airflow back over the wing’s upper surface allowing continued lift and control.

As a hummingbird’s flying style enables it to hover, it does not need to constantly move through the air. It has no need of alulae to prevent stalling, and being extra baggage, evolution has removed them.

It was the juxtaposition of watching an osprey deploy its alulae and a hummingbird not do so that finally made me suspect that the latter actually lacks them. A literature search confirmed the insight.

An Osprey deploys its alulae (the small extra feathers at the bend of the wings) as it lands at its nest.

A hummingbird can hover and so is unconcerned with stalling. It lacks alulae.

Posted in birds | 4 Comments

Bird collisions

 

Do birds collide in flight?

Yes.

Unfortunately, this question is often begged (question’s answer assumed rather than sought), so it is often phrased as: Why don’t birds collide when flying close together? A responder then must struggle with the daunting task of explaining the truth of something that is false. 

Now, birds are remarkably good at avoiding collisions and this fact does merit an explanation. However, they are not perfect at it. While avoidance is important, equally important seems to be the rapid recovery from inevitable collisions.

This shot into a flock of Snow Geese shows two collisions. In the upper centre right, two birds are colliding, while in the lower centre, three birds are.

Earlier this week, I was watching Cliff Swallows coming and going from the nests they had built on a human structure. While ascending to adjacent nests two of them collided.

Interestingly, a fifth of a second later each bird had recovered and continued on its way.

Of course, I have been discussing inadvertent collisions. During an attack, a raptor frequently collides with another bird. Indeed, falcons will purposely collide with prey so as to kill it. I lack a picture showing this, but do show one of an eagle about to collide with an osprey in its (successful) attempt to steal the osprey’s fish.

Posted in birds, commentary | 1 Comment

Eagle chick

 

Three weeks later, I revisited the nest of Bald Eagles. Earlier, no chicks were visible. Now, a couple of chicks occasionally peered out. This is a picture of one of them. 

Posted in birds | 3 Comments

Osprey loyalty

 

If this issue has been settled, I don’t know about it. The issue concerns an osprey’s fidelity. Certainly, an osprey seems to mate for life, but is it being loyal to its mate or do both partners merely return to the same nest site each summer?

The question of osprey loyalty is one that might take many observations or experiments to answer. The answer is of interest around Kootenay Lake, which has an unusually high summer incidence of ospreys.

Today’s observations merely attests to osprey loyalty. It gives no insight into the reason for this loyalty, for an osprey had returned to the same nest as the previous year. 

I took this picture beside one of my favourite osprey nests in May of last year (2015). This osprey bears a band on its left leg — something rarely seen on local ospreys.

Today, I visited the same nest and photographed an osprey with, presumably, the same banding on its left leg. There is a loyalty to something.

Posted in birds | 2 Comments

Dipper chicks

 

For many weeks, I have been watching a dipper nest as I wait for the chicks first to arrive and then be old enough to peek from the nest as they are being fed. 

By displaying their yellow gapes, the chicks tell a parent: feed me. 

Posted in birds | 2 Comments

Human predators

 

We are all depressingly aware of recent vicious attacks made by individuals who believe they know the ultimate truth and that anyone who might think differently should be either cloistered or killed.  

My recent experiences fall well short of this level of megalomania. Yet, they are a symptom of the same mindset: destroy rather than build.

In the last two days, my blog has been under continual attack by those who would subvert it to their own sleazy purposes. Not content to promote their ideas or products on their own merits, they prefer to co-opt the work of others. 

I note that my blog is at most only of minor local interest. It discusses the wildlife, natural phenomena, and scenes around Kootenay Lake, Canada. Yet, in the last few years, it has been hacked twice and forced to (temporarily) promote irrelevant pharmaceuticals. At present, it is experiencing a third, ongoing, widespread, and coordinated attack, presumably with the objective of similarly turning it to the dark side. 

The attack on blog.kootenay-lake.ca is impressive in its scope. In two days, there have been over three hundred attacks and that number is still climbing. Here is a list of the countries (internet jurisdictions) from which attacks have so far arisen:

Abu Dhabi, Albania, Algeria, Argentina, Armenia, Australia, Austria,
Bangladesh, Belgium, Bolivia, Bosnia and Herzegovina, Brazil, Bulgaria
Cambodia, Canada, Chile, Croatia, Cyprus, Czech Republic,
Denmark, Dominican Republic, Dubai,
Egypt,
France,
Georgia, Germany, Ghana,
Hong Kong, Hungary,
India, Indonesia, Ireland, Israel, Italy, Iraq, Ivory Coast,
Japan,
Kenya, Korea (Republic of),
Lebanon, Lithuania,
Macedonia, Malaysia, Mauritius, Moldavia (Republic of), Montenegro, Morocco,
Nepal, Netherlands, Nigeria,
Oman,
Pakistan, Philippines, Poland, Portugal,
Qatar,
Romania,
Serbia, Singapore, Slovakia, Slovenia, South Africa, Spain, Sri Lanka, Switzerland,
Taiwan, Thailand, Tunisia, Turkey, 
United Arab Emirate, United Kingdom, United States, Ukraine, Uzbekistan,
Venezuela, Vietnam,
Zambia, Zimbabwe.

Three things are worth recognizing:

• Computers in many of these countries are responsible for not one, but multiple attacks
• It is likely that the attacks are coordinated from one location and that the owners of the compromised machines have no knowledge of what is going on
• The attacks are undoubtedly incidental to my blog’s specific content, arising only because the work of others is deemed exploitable. 

 Sigh. 

Posted in commentary | 6 Comments

A moose swims by

 

I watched a moose swim along a shoreline in the rain. Previously, I have only ever seen a moose swim across a lake. However, moose are comfortable in water and have been known to swim for twenty kilometres. This male only swam about 500 metres before coming ashore.

By the time it climbed out, the rain had nearly stopped.

It then wandered off through the brush.

Before climbing out, it stopped briefly to stare at my camera. However, a moose’s poor vision probably prevents it from understanding digital photography.

Posted in mammals | 4 Comments

Cedar Waxwings

 

Locally, we get two species of waxwings: Bohemian Waxwings in the winter; Cedar Waxwings in the summer. Bohemians course about in large flocks (see, waxing alliteratively, Bohemian Waxwings). Cedars are here to breed and so don’t move about in the same numbers.

The first Cedar Waxwing spotted yesterday was a fledgling. It lacked the silky feathers of an adult.

An adult flew in.

Cedar Waxwings are not seen locally in large flocks, but a few hang out together. Easily seen are the red waxy tips to the wing feathers after which waxwings are named.

Posted in birds | 4 Comments