Thunk

 

It seems that you are never too young to start a career of colliding with windows. Following a resounding thunk, this juvenile robin sat motionless on a porch roof below the offending window. After about ten minutes, it flew off. 

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Fawn not seen

 

A doe in my yard is clearly eating both for herself and another. I have yet to see the fawn.

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Lizard’s tail

 

When I was a small child, I chased a lizard across a scree slope. I caught it by the tail, which promptly disconnected and was left wiggling in my hand. The lizard made its escape; it had autotomized.

Autotomy (Gr: auto- “self-” and tome “severing”) or self amputation is the behaviour whereby an animal sheds an appendage, usually as a defence against a predator’s grasp. The lizard has a zone of weakness in its tail allowing it to break cleanly. A new tail is then grown.

When spotted yesterday, the Western Alligator Lizard had already shed its tail in response to who knows what. 

Initial views of the head of the lizard revealed nothing unusual.

A full view shows the lizard to be truncated. The coppery coloured back reveals that the lizard is young.

As the lizard walked, three sinews (tendons?) extending from the break whipped about as if still controlling a tail.

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Local Nature Tasting

 

This posting is shamelessly promotional.

At 7:30 p.m. on Tuesday, August 5th, I shall give a presentation at the Visitors’ Centre of Kokanee Creek Park (BC Parks’ map, Google’s map). Part of a weekly series, Science in the Park, my offering is entitled

Local Nature Tasting

It will mimic a celebration of local vintages at a wine tasting. 

Often for wine tasting, a theme is chosen and participants are invited to make new distinctions among subtly different varieties. As my tastes run to observing local nature, I have chosen themes from among my own pictures. Some themes feature colourful bears, dancing devils, perplexing bows, and, ta-da, local ogopogoes. Within each theme, assorted images encourage savoury distinctions; following each theme, a palate cleanser clears the way for the next. The local constraint is easy as most of my pictures were taken within or near the Park.

The title slide shows Trumpeter Swans at Kokanee Creek Park.

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Bat feast

 

It was an amazing experience to sit amidst a horde of hunting bats.

Derek Kite alerted me to the shoreline feast. For an short intense period in the late evening, the air above a tiny stretch of beach became filled with swift, silent bats feasting on hundreds of mating mayflies. Abruptly it all ended, only to be replayed the next evening.

Derek and I adopted different photographic strategies. He tried to record bats as they approached and left the feeding area; I tried to capture the action just offshore. Each approach had a remarkably low yield. We were, after all, attempting to photograph small, dark, swift flyers in unknown positions at night. His percentage of somewhat acceptable shots was about 1%; mine was even lower.

But, what fun.

In Derek’s first two pictures, the bats seem to follow a line of rocks as they leave the feeding grounds.

I managed one head-on shot over the water.

And while the bat (and its reflection) is soft, it does show one hunting amidst the crowd of mayflies.

Derek Kite’s pictures are used with permission.

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Alula landing

 

A bird’s deployment of alulae is a remarkably transient event. If you blink, you will probably miss it, for each event lasts less than half a second. Yet, it is fun to spot these bits of aerodynamic wizardry which perform the same function for a bird as do the slats on an aircraft.

Half way along the leading edge of bird’s wing there is a bend that is analogous to a person’s wrist. An alula corresponds to a bird’s thumb. It is usually held flush to the wing to minimize drag during normal flight, and so passes unnoticed. Yet, birds have the same problem as do aircraft. To land, they must slow, but doing so decreases lift and control. To minimize this loss of lift, the bird tips back to increase its angle of attack. This can lead to a stall as the air ceases to flow smoothy over the upper surface of the wing. A bird’s deployment of alulae forces the airflow back over the wing’s upper surface, allowing the maintenance of adequate lift and control.

I was watching a heron hunting in a marsh. And although I felt that my twenty-five metre distance would not be threatening, the heron thought otherwise and flew farther away.

It flew low over the grass to a spot about double the distant. The Great Blue Heron cruises at about 40 km/hr and now must come to a graceful stop. If it were landing in a tree, it could approach from below and use gravity to slow. However, on a level surface, its wings need to do all the work.

It begins to tip back. The increased angle of attack increases drag slowing the bird and also partly compensates for the decreased lift at the lower velocity. Alas, it also increases the likelihood of a stall with its loss of control. At this time the alulae are deployed. They are the raised feathers halfway along the leading edge of the wing (at the wrists).

With its alulae still deployed, the heron tips back even further. The ruffled upper coverts (feathers that cover the wing) probably play the same role as vortex generators on aircraft wings.

Alulae are no longer needed as the heron swings its feet forward to alight.

And all of this was seen because the heron apparently wanted to double its distance from me. Successive landing pictures were separated by about a fifth of a second and the alulae were deployed in two pictures—about the time span of the blink of an eye.

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Shore patrol

 

The darner season is upon us. 

Darners are a group of large, colourful, dragonflies that relentlessly patrol shorelines for insect prey. Happily, they are voracious eaters of mosquitoes. Unlike some groups of dragonflies that hunt from a perch—and so are fairly easy to photograph—darners are almost always seen on the wing. Photographically, they constitute a small rapidly moving target many metres off upon which framing and focussing is difficult. Many shots are taken; few are successful.

This Paddle-tailed Darner is patrolling the shoreline. To ease flying, its legs are tucked out of the way. 

When the darner turned roughly in my direction, its sunlit wings flashed like a burst of fireworks.

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Wood Duck chicks

 

I don’t suppose that any local birder would doubt that Wood Ducks breed around the Lake. Yet, they are remarkably secretive about doing so. Frequently seen are the chicks of Mallards, Common Mergansers and Canada Geese, but not Wood Ducks.

At least, this is the first time I chanced on Wood Duck chicks. Curiously, despite the large number of campers at Kokanee Creek Park, this skittish species was secreted not far from a busy campground.

There were at least four chicks, but only the mother and two of them appear in this grab shot taken though foliage just before they all vanished, presumably as a rebuff to my presence—although, I really wasn’t all that close. 

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Sapsucker

 
Male Red-naped Sapsucker, 2010

 

For a week I have been visited by sapsuckers. 

Early one morning a week ago, I first heard and then spotted two sapsuckers on a utility pole, but managed a picture of only one of them before they both flew off. That bird, posted to recent birds and reproduced below, is a male now identified as a Red-naped Sapsucker.  

Since that time, I have heard a sapsucker a half-dozen times but only managed a few more pictures, always of a female Red-naped (one of which is below).

The odd thing about this is that sapsuckers drill holes in trees and then sip the sap that flows. Certainly, that is how I have seen them before, as in the shot of a male working his way around a mountain ash (on the right). This time the sapsuckers seemed to confine themselves to the utility pole, something that clearly lacks sap. They were probably drumming on it to communicate, rather than feed.

This is the first sapsucker (male) seen a week ago.
Its partner went unrecorded at the time.

This is one of a few pictures of the female captured over the subsequent week as it hammered on the pole. Although it was primarily in the shade, there was a moment when shifting leaves allowed sunlight on its red crown.

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Anise Swallowtail

 

In Acorn and Sheldon’s book, Butterflies of British Columbia (Lone Pine Publishing, 2006), the Anise Swallowtail is described as

the most common swallowtail west of the Rockies.

Locally, I have had frequent views of both Western and Pale Swallowtails: e.g., butterfly love, yard delights, butterfly symposium. Yet, it was not until a couple of days ago that I saw my first Anise. Further, another long-time butterfly watcher at the north end of the Lake, saw her first Anise only a month ago. 

How is it possible that what the experts claim is common goes substantially unseen by keen local observers? I don’t know, but a clue might lie in the fact that we live in a well treed region and, as Wikipedia notes:

The Anise Swallowtail is a butterfly of fairly open country….

Could it be that those authors were more familiar with the open countryside of the central southern regions of the Province than they were of the forested West Kootenay?

This Anise Swallowtail rarely opened its wings after it alighted, so it was difficult to get a classic shot of spread upper wings. However, this picture provides a definitive view of the top of two of the four wings.

Male butterflies often sip moisture in wet sand. The accompanying nutrients apparently increase fertility.

An Anise Swallowtail Butterfly sets out to increase his fertility.

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