Saturday, December 12, 2009

Aerial Combat over Lake Tapps--Bald Eagles and a Duck

Photo by Gary Wheeler
A wonderful visual sequence sent in by Robin of Illinois, the original blog link is--
(Correction on the blog address-- )
As per the blog, the narrator and the photographer are Gary Wheeler.

For the original narration check the original blog above. Blogger is having a wee bit of problem these days with copy and paste so I'll give you the general idea and you can go to the link for the details. It concerns a mature Bald Eagle who is attempting to nab a duck.

Photo by Gary Wheeler
But the duck, being no dope, dives into the water and comes up in a different spot just after the eagle flies by each time. This goes on for awhile--and then eventually another eagle appears and that dear readers is the scenerio in a nutshell.

Photo by Gary Wheeler

Photo by Gary Wheeler

Photo by Gary Wheeler

Photo by Gary Wheeler

Photo by Gary Wheeler

Photo by Gary Wheeler

Photo by Gary Wheeler

Quicksilver Gets What He Wants and a Charlotte Update

For those who asked after Quicksilver, he's doing just fine except for his penchant for getting off his play areas and gamboling around on the floor under Pyewackit the cat's stealthy observation. Today he decided he'd stay put if I gave him an unlimited supply of tropical fruit nutri-berries and played the video SWEENY TODD over and over so he could watch it--over and over.

Who knew he'd like bloody musicals starring Johnny Depp.

And nest news from Brett Odom the sharp eyed observer of Charlotte and Pale Male Jr. at the 888 nest--
Yesterday, (Thursday December 10th), Charlotte spent some time just sitting at the nest site on 888 7th Avenue. It was around noon, so she wasn't roosting there for the night. Also, on Wednesday, there were two hawks soaring above the 888 building. One was Charlotte and I am guessing that the other was a foreigner. I doubt it was Jr. since he always disappears during the winter, and Charlotte eventually chased the hawk across the river into NJ.

And in answer to a question of mine--
Oh, and Ziggy hatched April 30. The 2009 egg should have hatched sometime between April 18 - 27 if it had been viable.

Sorry this is a short one, more coming up after I've actually finished shoveling all the 16 inches of snow that is clogging up life.

During the snowfall I was attempting to get some snow off as it arrived so was shoveling at 2 in the morning. It was a very wet heavy snow, which was sticking to all the trees particularly to the conifers. I'd been hearing branches crack around the neighborhood, when an extremely large crack sounded above my head in one of the Spruce trees in the front yard. I dived for the front porch, it has a roof, just as a major branch came plummeting out of the sky near where I'd been standing to a chorus of House Finch danger calls. The House Finches "own" the Spruces in the front yard as the Juncos own the ones in the back.

After deciding no more were coming down, I checked to make sure nobody had come down with the bough. No little trapped birds so I suspect they all made it. And after fleeing likely came back in a few minutes and snuggled back in on another branch.

Donegal Browne

Wednesday, December 09, 2009

The Thunder Snow Storm Plus a Pyewackit Update

I can't stay on long as I'm in the middle of a Thunder Snow Storm and don't want to take the chance of surging out the computer. Thunder Snow Storms just don't or rather didn't happen. They are remarkably unusual here. I've yet to figure out why they don't happen as often as regular thunder storms but will keep looking for the explanation. The first TSS anyone can remember occurred the year before last and this evening there is another huge one going on.

The digital camera takes the flakes and I suspect because it catches the aura of sparkling light around the flake, turns them into something similar in shape and even color at times to soap bubbles--nearly a foot so far.

Earlier I looked out when it was only snowing moderately and noticed a lump up on the Crow's Goodie Stump. I turned on the outside light but it's circle didn't illuminate much. Still a large lump. A raccoon? So I grabbed the camera and went out and I was surprised that what ever it was stayed. Some will remember I originally saw Pyewacket out on the stump eating pasta. And this visitor turned out to be a cat as well, only this one is large and chubby. Whether this is a neighbor's cat out for a snow romp or a stray, I assume will become clear eventually.

Speaking of Pyewackit, here is a much filled out Pye compared with the initial version when she first came in out of the cold. Also giving me a look, she isn't partial to the camera--she is partial to my giving her the catnip that she's asking for, which I'd fully expect from her namesake who lived with a witch in the comic play, Bell, Book, and Candle.
More as weather and electricity permit.
Donegal Browne

Sunday, December 06, 2009

Silent Flight and Owl Feather Structure Plus John Blakeman

Photograph by John Blakeman

When I opened my email box I was very pleased to find this grand photograph from our raptor man in Ohio John Blakeman--

Here's a macro photo of a great horned owl's leading edge left wing feather, showing the structures that silence the wing.

John Blakeman

Thanks John, for the terrific macro shot of the fimbrae, those fringes or serrated looking feather edges on the leading edge of the primaries which are thought to turn big turbulence into any number of mini-turbulences thus decreasing sound. As to exactly how, now there lies a question amongst scientists.

Actually I've been thinking about owl feathers all day, as the deeper you dig on this, like in most science, the more disagreement about what is what, the how, and why, begins to rear its head.

But first some factoids in which I haven't discovered much disagreement--yet.

As we know, birds molt and owls are no exception. They molt in a specific pattern after their young are raised for the season and it usually takes no longer than three months to complete the process ending with all new feathers. Obviously if you are a bird you don't want so many feathers missing at any one time that it affects your ability to do your bird business.

In the case of owls on the U.S. side of the globe, everybody except Barn Owls molt their flight feathers from the inside towards the outside. Barn Owls, always being different, I mean they started out living in caves before barns were available after all, molt their feathers from the center first and replace them on both sides as they go along from there.

As to tail feathers they drop a few at a time. Again the exception, in this case some of the small owls drop all their tail feathers at once. (Now what is the evolutionary advantage of that I wonder?)

Okay, they've got new feathers now but just how do they contribute to silent flight. First off if we're going to be picky, they don't have silent flight, they have flight in which the vibration is more than 2000 hertz so we, the owl, and the prey likely can't hear it, except as pointed out previously-- moths and bats may hear them just fine.

Not only do the fimbrae turn big turbulence from major to any number of mini-turbulences but the secondary feathers across the wing are particularly soft so they may be absorbing sound or turbulence, actually possibly two different things, and the trailing edge of the wing is described as "ragged". Ragged? So far I've not found a macro shot of just specifically in this case what ragged is.

That's really how the digging started.

And, oh dear, the disagreement is major.

First off remember I'd said that owls don't seem to have much in the way of down feathers? That is only true if you decide that the feathers on the legs of Great Horned Owls and the legs and feet of Snowy owls for instance aren't down feathers. Those sections of those owls are certainly covered with fluffy feathers that look like down in the long view, but in some cases they're named by some scientists to be something called something else besides down.

More digging.

So what is the purpose of those feathers? Well, the no-brainer answer by many for the reason Snowies have long fluffy feathers on their feet is they hang out in the Arctic where there aren't a lot of trees to perch on so it helps keep their feet warm while they're standing in snow.

Seems plausible right? And may well be true, but then why do some number of larger owls have extremely fluffy legs as well as some feathering, perhaps of a shorter nature like the Great Horned Owls, on their feet where there are plenty of trees? They don't all hang out in the Arctic after all.

I dig some more.

Another why? Some say, because all that fluffy feathering on their appendages helps decrease sound while in flight. Just how any feather is definitively decreasing the sound of flight is still under hot debate by the way, so that's just one more cherry for the top.

Dig, dig, dig.

Aha! I find an abstract of a paper (a very long abstract) that is comparing the morphology (as it relates to size) of the feathers and their parts of pigeons, Columba livia, and Barn Owls, Tyto alba pratincola. Pigeons being very noisy flyers (not a bad thing for pigeons, being flock birds who practice tactics against predators--my supposition-- or we wouldn't have any) and Barn Owls, being members of the owl silent squad. The two species also weigh about the same so weight isn't a differentiating factor for the feathers. I must say the birds are certainly shaped differently, at least when it comes to birds, but you have to give the science guys a break somewhere.

So far , I've learned that the vanes on those secondary feathers on the owls that supposedly help damp sound and the secondaries on pigeons which one would surmise don't, start out by the skin with the same radius but in the owls, they diminish in size more rapidly as they go than does the pigeon vane.

How might that affect the integrity of the feather in the owl? It makes it less stiff and well--softer, wavier--gulp, dare I say it? It gives the feather the beginnings of FLUFFY.

More as it susses itself out.

Donegal Browne