Wednesday, August 30, 2006

Goose confusion...

When I lived in Fort Collins, I paid a moderate amount of attention to the Canada Goose diversity, discovering like everyone else did that it is confusing. Now that the species has been split, it's a much bigger concern for the birding community as a whole. And I'm now even more confused, not so much about what I saw myself, but about what other people are reporting.

As I recall, the large majority of the small Canadas I saw looked to me like parvipes birds, the "Lesser Canada Goose." I saw only a small minority of birds that struck me as hutchinsii birds. Andrews and Righter reported that on a statewide basis, hutchinsii birds were "very rare."

Now comes the split, and I look at the most recent years' Colorado CBCs, and I see that about 1/3 of the "Canada" Geese are now being reported as Cackling Geese. This is similar to the proportion that used to be reported as "Canada Goose (small forms)" before the split. But but but but...

The parvipes birds, which seemed to me to constitute the greater part by far of the "small forms," were NOT split off as Cackling Geese! These are still considered Canada Geese. The subspecies that were split off as Cacklers had looked to me like only about 1% of the total birds, not 30%.

So this is what I am wondering now: was I wrong in my evaluation of the most common "small form" subspecies, or are Front Range birders now MASSIVELY overreporting Cackling Geese by including all these parvipes Canada Geese in the totals? What's the scoop from those out in the field there now? What do the specimens have to say?

Thursday, August 24, 2006

Puppy progress

The pups will be four weeks old tomorrow. They are cuter than the human mind can fully comprehend; they are also growing teeth. So this evening they had their first supplemental meal, a yummy (to their palate) gruel of oatmeal, dry milk, and dry dog food all blended up into a runny mess. They figured out this new game almost immediately. The first few stepped in it, looked down to investigate, licked some of the goo off their feet, and obviously thought "WOW!" In a flash there were ten pups gathered around two pie pans slurping and munching away. The only trouble was keeping mamma from eating their food; I gave her a portion of her own mixed with her dry kibble, which seemed to satisfy her and convince her to leave the babes alone to eat their own supper.

Tuesday, August 22, 2006

Luneau postings index

I'll try to keep this current and near the top of the pile, to make it easier for those who might be interested in tracking my analysis here:

Wingbeat graph
Animation of idealized flying Pileated
Animation of idealized Luneau bird
Luneau in 3D (estimated distances and angles)
Frame-by-frame animation of first 0.6 second of Luneau
Black and white, blurring, pixels, and underwing patterns

In all of this, please try not to comment anonymously. Thank you.

Monday, August 21, 2006

Luneau: Basics and the The Underwing

Jumping ahead a bit here, but there are some fundamentals about this that are rolling loudly in my head...

First, some starting points for understanding the black and white of the video:

White bleed, focus, etc.: Much reference has been made to the video exhibiting "white bleed," a contamination by excess white of the pixels surrounding a bright white pixel. But look at the edges of the tree trunks as they pass in front of bright sky, then gray background trees, and you will see that there is not really any white bleed. It has also been said that the video is poorly focused. Close up examination of the patterns of tree trunks shows that this is not the case, either. What the video is, pure and simple, is pixelated, nothing more. The illusion of poor focus is an artifact of the video presentation, in which the pixel edges are softened to make the image look less jarring and jagged. The pixels on that bird are HUGE, about 3 cm across early on, and larger later. This simple pixelation is plenty adequate to account for all the crappy resolution of the images. The other factor killing resolution is plain-and-simple motion blur. This is what causes the white expanse on the underwing to appear larger than it actually is, and obliterates details of the underwing. Go through the arithmetic:

The pixel resolution is about 3 cm or worse. To this add motion blur of several more centimeters on the wings (more than 10cm near the tips in some frames). We're not going to see things narrower than 5-10 cm that are aligned perpendicular to the wing's motion. Now look at the sizes of the underwing features that would differentiate the two species: The Pileated black trailing edge is about 3-5 cm wide; the Ivorybill medial black bar is of similar width. And these wings are not oriented face-on to the camera, so the apparent width of these features is even less than this. So of course these features are completely unresolvable in this video. Either species would be expected to show a big white blur under its wing and nothing else. In the CLO analysis they argue that the Ivorybill black bar would be obliterated, but the Pileated black trailing edge should be visible. Given that the two features are of similar width, this is argument does not hold up.

The one black feature of the underwing that is visible consistently is a black wingtip. This is especially clear in the second half of the downstroke of many frames early in the flight sequence, where it is smeared into a consistent black arc. Bevier and others have argued that this is a specific Pileated characteristic, and its presence is a key point they use to conclude that the bird is a Pileated. This makes no sense, however. Both species have black wingtips when viewed from below. The distance from the wingtip to the distal end of the underwing white is quite similar in both species, comprising about 20-25% of the total wing length. I do not understand, therefore, why the presence of a visible black wingtip provides any information at all to identify this bird.

Conclusion (and starting point for further analyses): The underwing pattern of the flapping wings in the Luneau video does not provide any information at all to help determine the species of the bird. Both species would be expected to show white underwings with black wingtips and no other markings under these conditions.

But what about the black wing edges that are visible in these early frames? Other than the wingtips, they are artifacts. They are not consistent between frames, and they appear both on the trailing and leading edges of the wings with approximately equal frequency (neither species should show black on the leading edge of the underwing except at the tip, where both should show it). They also frequently align with darker areas in the background. The blurred wing images are semi-transparent, and they often meld with the background deceptively. The black spots on the wing edges are garbage, noise, useless; not information.

So, I have just thrown out the most prominent plumage characteristic in the video, the big fat white underwing with a black tip, concluding it is useless for identifying the bird. What is left? Good question. I don't think (yet) that the answer to that is "nothing;" but I make no guarantees.

Wednesday, August 16, 2006

Atlas memories

Continuing to archive my field notes into e-bird, I'm now reliving my South Carolina Breeding Bird Atlas days. Those were some really nice days of summer birding -- peddling around the dirt roads of the flatwoods and swamps on my mountain bike, listening to all the voices of the woods. I had Georgetown and Horry Counties almost to myself, it seemed. I vividly remember finding all those unexpected warblers nesting in the bottomlands -- Redstarts, Black-and-whites, Worm-eatings, Ovenbirds, etc. Plus the occasional Swallow-tailed Kite sailing overhead... and the Black Bear tracks in the trails. I do enjoy atlas work. Online summaries of the results are available in several places, including:

The BBA Explorer
South Carolina Breeding Bird Atlas

The blocks I covered were Bucksville #2, Cedar Creek #4, Dongola #6, Georgetown North #4, Georgetown South #4 and #6, Horry #3, Outland #6, Plantersville #2, Rhems #6, Wadboo Swamp #1, and Walterboro #4

Where the Luneau stuff is going...

I still have a lot to do on it, so it will be a while before I put up the final postings. But I am already getting a sense of where this seems to be taking me. I have a feeling I'm probably going to wind up pissing everyone off. Don't expect to see my results featured on either Tom Nelson's blog or the Cornell website...

Tuesday, August 15, 2006

More Luneau chicken scratches

The de-interlaced, 4x magnified digital video clip from which these animations are derived is copyright 2004 by David Luneau, and is available from Science Magazine Online, among other sources.

This is rough, some frames (like field 316) are real clunkers and need major reworking. But here is my rendition of the first 0.6 seconds of the Luneau video flight sequence. I show only the bird, always centered in the frame. I primarily focus just on the wing shape, with less attention paid to the body. The sketches are estimates/interpretations of the wing positions at about mid-exposure, without motion blur. Other penciled annotations include the field number as assigned in the original Science publication, and a little arrow beside the body showing its apparent direction of motion relative to the background. The size of the bird's image is kept the same, I did not draw it shrinking with distance. Once again, this is a rough first cut...

344kB Quicktime animation

Notes --

The bird's positions and postures while it is behind the tree are of course conjecture. Yes, I realize the bird looks like a cross between a pigeon and a grouse in my drawings of these frames. The main point is to approximate the missing 1.25 wingbeats while the bird launches and rolls into flight attitude while remaining entirely concealed behind the tree.

I have rejected Cornell's closed-wing interpretation for fields 33 and 50 (the second and third frames) in favor of the extended-wing model shown. I agree with many commentators that this fits better with the rhythm of the visible portion of the flight sequence, the relative sizes and positions of the exposed parts of the bird, and the documented actions of Pileated woodpeckers launching in to flight from near-vertical perches. There are, of course, no movies of Ivorybill launch sequences available for reference. Note that, in my interpretation, the visible wing in field 33 is extended both upwards and away from the camera, hence its apparent length is forshortened. This behavior is demonstrated well in several of the Pileated comparison videos posted by Cornell on their Luneau video analysis web pages; plus it just makes sense that the bird will extend its wings away from the tree to prepare for the first power stroke that will carry it into clear space.

This sequence covers up to the point that the bird becomes more or less stationary relative to the background, just before it curves left and upwards. In the final frames of this animation, the bird is travelling almost exactly away from the camera. There is no point in this sequence at which any dorsal surfaces of either wing are definitely visible during a downstroke. This issue is not entirely clear for the left wing in the early downstroke frames of the first wingbeats (fields 233-250, 350-383) and has been the subject of controversy; I'll discuss that more in later postings. It is clear that the inner portion of the left wing in these frames is viewed close to edge-on; any slight shift could reveal dorsal or ventral surface. Again, more on this later.

Monday, August 14, 2006

Big Rig Birding: "A big 10-4 on that Phainopepla, Good Buddy"

[Actually, truckers don't call each other "Good Buddy" any more. That term has acquired a whole new, not G-rated, meaning. It's been replaced with "Good Neighbor;" but really, we mostly just call each other "Big Truck" and "Driver" or whatever company name happens to be scrawled across our trailer this week.]

In 1999, I ditched the Academic thang, went to trucking school, got my CDL, and became a long-haul trucker. I worked at this full-time through most of 2002, and part time since then when my primary job became farming and restoring the house. I've never regretted the career change for a second. I've rolled down nearly every mile of every primary Interstate in the lower 48, plus a hell of a lot of the 3-digit ones and untold legions of other two-lanes, four-lanes, city streets, and country roads... many of them over and over and over. I used to have the run from Denver to Grand Junction via the Eisenhower tunnel and Vail Pass for breakfast three days a week; I picked up 20 tons of Coca-Cola practically in the shade of Shea Stadium; you get the point. Like the song says, "Up to the Colorado mountaintops / down to the desert where Reno stops / north to the green of Couer d'Alene / there ain't no road that we ain't seen"

One of the things that all this driving produced was tons and tons of scribbled bird notes. With the time demands of the job, birding was done on the fly: 15 minutes in the woods behind a rest area in Oregon, trying to sort out gulls while dealing with traffic on I-880 along the east shore of San Francisco Bay, an Anhinga soaring over I-95 in South Carolina, etc. And no, I never hit anyone. Birding is always secondary to the job; no Glaucous Gull is worth a squished family in a station wagon or a mangled motorcyclist. But there are many many miles of quiet time on long rural runs, and ticking off what you can manage to identify out the big wrap-around picture window of your mobile office helps keep the odometer rolling.

I came up with a fairly organized scheme for records. I just kept lists of species identified along stretches of road that were mostly defined by changes in the landscape. For instance, the run on I-70 from Denver to the Eisenhower tunnel splits up as piedmont (the plains), foothills (oak/pine/grass/scrub), lower montane (ponderosa), upper montane (lodgepole/aspen), and subalpine (spruce/fir too high for aspen). As you can imagine, each list was often only a few species long. It's only been this summer that I have finally compiled all these years of teeny little lists, and the results were very surprising to me:

My "Truck List" stands at 271 species! I was astounded at how high the tally ran when I combined all these single-digit lists of mostly common species, all across the continent. Top THAT out of YOUR office window! Unless you are a professional bird guide, of course...

I counted birds seen from the truck, or anywhere that I walked to from the truck. And of course I pool together all the dozens of different trucks I have driven. When team driving, all time counts regardless of who is behind the wheel. As you'd expect the list is heavy on birds like corvids (12 species) and raptors (21 species), and light on woodland passerines (17 wood warblers, mostly gotten at rest areas and the edges of industrial parks). And in all that, only one lifer: a Common Black Hawk in Arizona. For comparison, my Truck list is higher than all but two of my State lists. And actually, there are still some notes missing that I might find as I continue to organize, so there might be a few more species added still.

Sunday, August 13, 2006

I just realized...

...a clever person should be able to deduce what ocean that is behind me in my profile photo, given that I was standing on the US mainland when it was taken (which I was).

Saturday, August 12, 2006

Attack of the killer Lorikeets

Took visiting family to the Nashville Zoo yesterday. One of their exhibits is a small aviary where you can be mobbed in a friendly way by hoards of Lorikeets. The birds are quite sociable, climbing on ears, hands, clothes, anything they can get a grip on. Some of them enjoyed climbing up and down my beard braids (which are about 18 inches long). It was terribly tempting to smuggle some of those cuties home. But, I tell ya, I have a new sympathy for Australian birders now. They had 7 or 8 species in there, and even at point-blank range it weren't no easy task to sort 'em out! I sure hope that in the wild they diverge in range and habitat, or there must be a lot of "Lorikeet, sp." entries in Australian field notes.

In another exhibit, they also have a Pileated Woodpecker, the only one of those and one of very very few woodpeckers of any sort I have seen in captivity. There was no docent handy to ask, but I guess it might be a rescued bird. Interestingly, it had white blotching visible on the wing coverts when perched, just like that shown in some of the photos of mottly Pileateds that came out or Arkansas. It looked like a result of either moulting or feather damage (from the confined environment, perhaps?)

Thursday, August 10, 2006

Cute puppy picture

The ten pups will be two weeks old tomorrow. Their eyes are just opening. This one wanted to say hello:

A little German sea chanty...

...if you're in a bit of a Viking mood


Alle die mit uns auf Kaperfahrt fahren,
müssen Männer mit Bärten sein.
Jan und Hein und Klaas und Pit,
die haben Bärte, die haben Bärte.
Jan und Hein und Klaas und Pit,
die haben Bärte, die fahren mit.
Alle, die Wale und Robben fangen,
müssen Männer mit Bärten sein.
Jan und Hein und Klaas und Pit,
die haben Bärte, die haben Bärte.
Jan und Hein und Klaas und Pit,
die haben Bärte, die fahren mit.
Alle die Hölle und Teufel nicht fürchten,
müssen Männer mit Bärten sein.
Jan und Hein und Klaas und Pit,
die haben Bärte, die haben Bärte.
Jan und Hein und Klaas und Pit,
die haben Bärte, die fahren mit.

Wednesday, August 09, 2006

Free and Clear!

Peggy did the closing today on a refinance of our farm. She got us a better loan that uses only the 30 acre tract that the house is not located on for collateral. This means we now own the house and the 8 acre tract it sits on free and clear, no loans, no leins, no nuthin!

Yee haw!!

I've never truly owned a house before; they've always been owned by a mortgage company that let us live in them so long as we kept up the payments.

Tuesday, August 08, 2006

Shorebirds and butterflies...

...have lousy taste in habitat.

Many butterflies, as anyone who indulges in the time-honored country pleasure of "watering the trees" in his own yard is aware, are especially drawn to urine and other "waste products." And shorebirds, well, we all know the sorts of places THEY like to hang out when migrating through the landlocked regions (nose plugs, anyone?).

I finally found a local shorebird hotspot today. I've been questing for one since July. First I checked out the Busseltown unit of the Tennessee NWR for the second time -- nary a one, not even a Killdeer. Last time there was at least one single Least Sandpiper. Later today on the way to shopping in Columbia I checked out the phosphate tailings areas northwest of that town. The facility is now owned, posted, and fenced off by "Solutia." Once they had a wildlife viewing area, but we are in a brave new world of strip mining now, environmental consciousness be damned. There were still two roadside pullouts where ponds could be glimpsed -- some Great Egrets, cormorants, a Great Blue, no shorebirds. Then, wandering the backroads looking for anything promising, I came suddenly across a horribly muddy hog-filled farm pond; an oversize hog wallow, really. With a ton of Canada Geese on it. And a shoreline bedecked with Killdeer after Killdeer. And, sure enough, in the smelliest, yuchiest spot in Maury County other than the MacDonalds in the Super Mall-Wart... Pectoral, Western, Solitary Sandpipers, Greater Yellowlegs... all lined up for easy viewing.

At least it is in a pretty hollow along a scenic backroad, since I'll be visiting it now every time I go to Columbia!

A p.s. about all the video stuff

My goal here is to create a frame-by-frame animation of all of the 60 or 70 or so fields of the Luneau video that show the Mystery Bird with any sort of resolution of color and shape. I want to be able to use reasonable, consistent dynamics on the wings, hence these preambles and sketches of idealized birds in level flight. I then want to see if the bird can actually be matched in every frame, frame-by-frame, with either a Pileated or an Ivorybill, or if in fact BOTH species can be made to match with small aerodynamically, anatomically, geometrically, and behaviorally realistic and consistent tweaks to the interpretation. Not gonna happen tomorrow, but I'll work along at it and post updates as I go.

The general impression in the mass mind is that this video has already been argued to death. True, it has been ARGUED extensively, and single frames have been analyzed intensely. But overall, as a MOVIE, not just as selected stills, it has not been thoroughly examined with the individual frames in the context of all the others frames, as an integrated sequence. It should have been, long ago, but no such analysis has been published either in the literature or the blogosphere that I have ever seen. And I got tired of waiting for it So, this longhair backwoods chicken farmer is taking a crack at it.

Monday, August 07, 2006

Luneau in 3D

Much argument about the Luneau bird has centered on whether or not any dorsal surfaces of the bird's body or wings are ever visible, and no consensus has been reached. It seems to me a key factor in this is to actually try to determine what the bird's trajectory is through space -- where it is gaining or losing altitude, and how much. Understanding that a bird is neither a missile nor an airplane, its body is not necessarily aligned perfectly with its direction of motion, its wings are not planes, it is still an important clue to know what the bird's motion is relative to the earth's surface and relative to the camera.

Many things make this difficult: the video is shot from a tilted camera in a rocking, moving boat, there is no fixed reference point at great distance, the lack of focus and unknown size of the bird make precise determination of its distance from the camera impossible, etc. But I did the best I could. For a reference I used one of the black blobs in the distant background of the upper left portion of the zoomed in frame. For distance determination I used Cornell's estimate of 20 m as the initial point, and watched how the "white spread" (horizontal spread of the white band along the wings in mid-downstroke, whatever part of the bird this white represents) of the image declined over time. I also used Cornell's number of 30 cm as the diameter of the tree trunk for a calibration. To correct for tilt I looked at the water surface and moss bands on the tree bases where they are visible in the bottom of the frame, and aligned my frame of reference accordingly.

I came up with an estimate of 10-12 m/s as the speed at which the bird is moving away from the camera. This seems like a reasonable speed for a fleeing large woodpecker. I wasn't able to resolve changes in speed over time given the bluriness of the images.

An important point that came from this is that it appears the bird is never really losing altitude. The impression that the bird is dropping initially is an illusion caused by the tilt of the camera and its travel away from the observer. It starts about 1.3 meters above the water, and remains at nearly this same height for the first 0.25 second or so. It then ramps upwards gradually, and in the latter part of the segment before it passes behind the next tree trunk about 1 second later it is climbing upwards at roughly a 10 degree angle. At that point it is about 4 degrees above the invisible horizon, thus its line of travel is tipped upwards towards the camera at a 6 degree angle. At that viewing angle, it seems rather likely to me that you will indeed see some dorsal surfaces on the bird's back and on its secondaries (at least the inner ones) during the downstroke. The bird's angle of ascent significantly exceeds the camera's viewing angle beginning about 0.5 second after it first launches from the tree. While the forward rotation of the distal portions of the wing in flight probably precludes ever seeing the upperside of the outer portions of the wing, the same is not true for the proximal (and trailing) sections of the wing. I think it is unreasonable to assume a priori that the upper side of the bird's inner secondaries could not be visible in these frames. I think it rather likely that they will be visible in some frames. In fact given what appears to be a quite strong forward "twist" to this birds wings in flight, it is quite conceivable that we would simultaneously see dorsal surfaces of the inner secondaries and ventral surfaces of the outer primaries at the same time on the same wing when viewing from slightly above the plane of travel.

Animation of Luneau bird

EDIT August 9 '06 -- watching real birds fly these last few days (pileateds, great blue herons, etc.) it's clear that I missed one detail in both these movies: the way the tips of the outer primaries flex smoothly upwards during the downstroke. That will be incorporated into future sketches.

My original intent of putting together the Pileated animation was to then paint it up like a Pileated and fit it to the Luneau video frame-by-frame and see if it really can be made to match. I hit the first bump immediately. The flight mechanics and wing postures of the Luneau bird don't match up with that Pileated animation. So, I put together a new animation of the Luneau bird:

232kB quicktime movie

As before, the animation is at half speed so it will match a deinterlaced 30 fps digital video. It shows one "typical" wingbeat repeated three times; download it and play it in a loop, click through frame by frame, etc. The Luneau video provides no actual side views, so the side views in the animation are based entirely on interpretation and extrapolation from the rear views. As with the Pileated, at all positions in the downstroke it is the ventral surface of the wing that is visible in the rear views. This is going to be true of most any bird that is flying exactly away from and on level with the observer. And of course the Luneau video does not actually resolve any of the particulars about the shape of the bird, so I have used a normal Pileated body as the model to fit the flight mechanics to.

The stumbling blocks I hit when trying to match this bird up with Pileated flight:

Most glaring is the shape of the wings early in the downstroke. In every wingbeat, the Luneau bird holds its wings with a strong downward bend at the wrist from nearly the beginning of the stroke. The Pileateds sometimes showed bowing of their wings, but primarily in the first flap or two after launching from a tree while still making the transition from perched to flight; and most notable late in the downstroke. In contrast, the Luneau bird shows bowing strongly and early in each wingbeat. Indeed, the Luneau's birds wings appear to straighten towards the bottom of the stroke, at the same point where a Pileated's wings are most likely to bow.

The apparent length of the white underwing at maximum upward extension (frame 1 in the movie) is considerably shorter than the apparent wing length in the other frames. This patern repeats on every wingbeat in the video. I interpret this to mean that the wing is not fully extended in its uppermost position at the start of the downstroke. This consistent with the wing bowing observed in the frames immediately following this. During a rapid upbeat with the wings close to the body (as shown by both the typical Pileateds and the Luneau bird), the upstroke consists of two stages. First, the humerus (innermost wing bone) is raised whle the rest of the wing remains folded close to the body, oriented downwards. Then in a quick rotation, the outer wing is raised and extended. In the case of the luneau bird it appears that this second stage is not carried out to full extension; rather the outer wing reaches outwards (and probably forwards) to begin the downstroke without having been raised to a full upright position.

A final point is difficult to judge because of the fuzziness of the video. However, it appears that the Luneau bird might show a more pronounced rotation of the outer wing on the downstroke (probably a direct result of the bowing of the wings) than does the "typical" Pileated. When the bird is positioned most nearly in direct line away from the camera, the amount of white underwing exposed on the downstroke increases dramatically away from the birds body, sometimes giving the impression of two white orbs suspended in space on either side of a wingless body. This could simply be a function of motion blur which would also increase distally on a moving wing; it is hard to say.

Overall, the differences between the flight of the Luneau bird and that of the typical Pileated are of a magnitude similar to differences routinely used in the field to distinguish seabirds on pelagic trips; perhaps comparable in degree to the differences between Cory's and Sooty Shearwaters, or Wilson's and Band-rumped Storm Petrels. They are perhaps similar to what one might expect to see in two large woodpeckers that are superficially similar but in fact are in two different genera. Alas, differences of this magnitude per se are not generally sufficient to document high-level rarities without other supporting evidence. But they sure are suggestive and make it hard to simply agree with a declaration that the Luneau bird is a perfectly ordinary Pileated showing nothing at all that is inconsistent with this identification.

More to come, someday...

Friday, August 04, 2006

Meanwhile, back in the holler...

What a quiet time of year. The birds are out there, but we're into the season where it takes pishing and perseverence to find most of them. The passerines are moving around, but so far I haven't seen any signs that they are moving any long distances. Just post-breeding dispersal; I haven't yet seen anything but a few shorebirds that isn't a breeder within a county or two's distance from here. Nearby NEXRAD isn't showing consistent against-the-wind nightime movement of anything yet either.

Purple Martin roosts have been impressive on the radar in the morning in recent weeks, though. For a while we had birds from the huge Wheeler roost (northern Alabama) arriving here every morning around 7:30, with a few dozen sticking around to ornament the dead trees and flycatch over the pond all day. The haven't shown up in recent days, though, and the radar images are suggesting that the roost is thinning out, too.

Animation of flying Pileated Woodpecker

An aid for interpreting videos of large flying woodpeckers...

I studied the Pileated flight videos frame-by-frame, which actually give a quite good study of the species at every stage of the wingbeat from multiple angles. I also examined references on bird flight mechanics. From this I created this sketchy, hand-drawn animation of a pileated in flight. This shows a bird flapping continuousy, as the do initially when just flushed from a tree, viewed from the side and behind, at HALF SPEED. It compares directly with a de-interlaced 30 fps digital video, such as the Luneau video from Arkansas. It is slow motion (1/2) when compared to a regular interlaced 30 fps video such as the Nolin video and most of the Cornell videos. The loop shows two wingbeats (the same 10 frames played twice); download it and play it as a loop, or click through it frame-by-frame, as you please.

220 kB quicktime video here

Notes --

The flight mechanics in these videos were actually quite consistent during the segments after the immediate post-launch stroke (where the bird is rotating and attaining proper attitude), and before the bird begin its approach to the next perch. The wingbeat I animated is one of typical speed; both faster and slower ones occur.

In the rear views, the wing surface visible in every frame except for the two upstroke frames (numers 9 and 10), and including the full upward extension frame (number 1), is the underside.

Actual woodpeckers are of course never positioned exactly like this relative to observers or cameras.

When I have a chance I will put together some additional animations that relate directly to the 2005 Arkansas "Mystery Bird."

Same comment rules as before; thanks.

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