Exploring Kootenay Lake

The Belted Kingfisher may be the largest bird in North American capable of (true) hovering.

Hovering flight is energetically expensive and only small birds can manage it. To stay in one spot in still air, the bird must generate lift solely by flapping its wings. Regular flight, where lift results from the bird’s forward motion through the air, requires only half the power of hovering. Large birds (with their lower ratio of power output to mass) just cannot sustain the energy output needed to hover. Sometimes a large bird appears to be hovering, but is actually holding a fixed ground position by flying into a strong wind.

I regularly watch hummingbirds hover—they are the masters of it. I knew that the significantly heavier kingfisher occasionally hovered when fishing, yet I had only ever seen it hunt from a perch. Hovering is exceedingly hard work; why do it when it isn’t needed?

Sunday, I watched a female Belted Kingfisher hover.

There was no wind, but the bird stayed fixed in space over the water. To enable details to be seen, separate images were first combined and then displaced—time moves like text on a page. One interesting detail is the bird’s use of alulae (Latin, for winglet). The kingfisher only deploys them on the downstroke, but retracts them during the upstroke. Unlike a hummingbird, the kingfisher is incapable of generating lift on the upstroke, only the downstroke.

Ten pictures in two seconds. Wings are folded during upstroke and spread during downstroke. The alulae are the extensions midway along the leading edge of the wing. They perform the same function as slats on an aircraft and allow the wing to achieve a higher than normal angle of attack. This maintains lift without resulting in a stall.

A detail of the final image is included to make it easy to spot the alula along the leading edge of the right wing.

The following composite does not show a kingfisher hovering but landing on a tree branch. The bird flies upwards using gravity to slow itself (images get closer together). At the last moment, when it has a particularly high angle of attack, the alulae are deployed.

There are no Harlequin Ducks in Kootenay Lake.

Gaining its name from the male’s almost comical plumage, this small diving duck prefers a cold turbulent stream to a warm tranquil lake. Although the harlequin does not visit the Lake, it can be seen from a road that links West and South Arms. Well, all of this is true in the summertime; in the wintertime (and in drabber plumage see comment, below), harlequins head to Pacific coastal waters.

The plumage of the male harlequin is almost gaudy—it is important to look good.

And this is true whether one is seen coming or going.

The White Pelican is huge, endangered, and here.

The White Pelican has an impressive wingspan of 2.4 to 3.0 metres, greater even than that of the Trumpeter Swan. Mind you, the swan outclasses the pelican in weight by about forty percent. However, a bird sighting reveals size not weight, so when the White Pelican flies low overhead, you know you have encountered an aerial giant.

This North American bird is not broadly endangered, but it is so in British Columbia where there is only a solitary breeding colony. That colony is in White Pelican Provincial Park, about 70 kilometres west of Williams Lake. Indeed to help survival, the Park is closed to the public during the pelican breeding season.

The White Pelican sometimes passes through our area during its migration. This May, it has been seen around the Lake from Creston north to Lardeau, and west to Nelson.

White Pelicans in the distance appear blurry and wiggly as a result of the intervening turbulent air.

Although the pelicans in the above picture were distant, fourteen others obligingly flew overhead.

You have to be impressed when one giant flies low overhead, but when a flock of giants does—wow.
I am indebted to Peter Mciver for showing me where I might see some White Pelicans.

No sooner than you think you are beginning to get the hang of watching nature, than an unknown species appears and sets you adrift. This was the case yesterday when I noticed that a black hawthorn tree had become alive with the twittering of small, plain, but melodious songbirds.

But, what was the bird? I took pictures (of course) and posted them to a birding group. It wasn’t long before Stanley Walens (in California) explained: “warbling vireos. They should be migrating into your area about now.”

And so it was. Here are two of my pictures of the Warbling Vireo as it entertained Kootenay Lake—what is missing is the delicious singing.