Jane Turner
Well-known member
I love the effort you have put in btw...
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Ivory-billed Woodpecker (formerly updates) (2 Viewers)
- Thread starter KC Foggin
- Start date
dave_in_michigan
Well-known member
It's been fun. If I had to do it, I'd probably hate it...
...Nah, it'd still be fun.
Dave
...Nah, it'd still be fun.
Dave
PandionMlt
Well-known member
yeah its the only reason i m still reading... might come in really useful one day
Jane Turner
Well-known member
You know Dave, I'm so tempted to go and video a bird over a reflective surface, in known conditions, and test you out 
If the bird is gaining height while flying, the velocity has to be smaller than in horizontal flight, because the bird needs to spend some work on the increase of its potential energy. As I understand this is the case in the video sample, one has to keep this in mind, when discussing the accuracy and usefulness of velocity estimates.
Jane Turner
Well-known member
To be fair to Dave, his estimate is for the vector (ie including the gain in height) The primary sources of error are the guestimates involved in estimating the height of the camera and the height of the tree.
dave_in_michigan
Well-known member
I see no reason why the bird couldn't be gaining speed while climbing... As Jane mentions, this is just Point A to Point B, straight line and average speed approximation. The actual speed may vary, but will have to be both above and below this calculated average speed.
I think the biggest source of error right now comes from estimating where "zero" is under the camera, and from using visual angles from that reference point to determine distances on the ground (B, C, D). I could be off quite a bit with those values. That's where ground measurements would really tighten things up.
You know Dave, I'm so tempted to go and video a bird over a reflective surface, in known conditions, and test you out
I'd love to see it! I'd be curious to see how you'd evaluate the known conditions to establish the baseline for comparison...
IBWO_Agnostic
Well-known member
Okay, this is fun and all, BUT, let's not forget Mike Collins has spent a LOT of time in this area, and has been unable to adequately document an Ivory-billed Woodpecker. If there are birds as he contends there is NO WAY he wouldn't be able to see the bird repeatedly and obtain photographs. I realize others my differ, but come on people. There is NO GOOD REASON this bird should be so hard to see adequately.
rob stoff
Well-known member
you're not taking into account that they may have rapidly evolved a cloaking device, you can't prove otherwise you know
Rob
Jane Turner
Well-known member
dave_in_michigan; said:I'd love to see it! I'd be curious to see how you'd evaluate the known conditions to establish the baseline for comparison...
I was thinking of mounting a graduated marker pole in reflection pool.... recording the flight of a released pigeon with a couple of reflective makers on them and using a 6 camera high definition 3-d recording system like this
http://www.qualisys.com/default.asp...g=Products&mainpage=templates/Q02.asp?sida=40
in addition to the crappy video I'll give to you... wonder if anyone fancies diverting some of the helicopter budget for this caper!
Vocally
The bird could simply be very rare, you know, like the Slender-billed Curlew. And as someone who posts on this thread has said elsewhere about the Slender-billed Curlew:
The people who seem to be most vocally against it are those who didn't see it it seems.
The bird could simply be very rare, you know, like the Slender-billed Curlew. And as someone who posts on this thread has said elsewhere about the Slender-billed Curlew:
The people who seem to be most vocally against it are those who didn't see it it seems.
dave_in_michigan
Well-known member
Sounds like a good plan. The 3-D modeling info will help with the CG animations for the movie.
You might want to consider this camera for a little better quality. You can pick up one of their current cameras now, and they'll let you trade in for full credit when the new one comes out.
rob stoff
Well-known member
The bird could simply be very rare, you know, like the Slender-billed Curlew. And as someone who posts on this thread has said elsewhere about the Slender-billed Curlew:
The people who seem to be most vocally against it are those who didn't see it it seems.
surely even you can understand the profound differences between the evidence of the SBC and that of any claims of IBWO, i.e. a series of images, videos and notes taken by multiple experienced observers of the same individual bird versus a few blurry images and mainly single observer reports from people with loads of IBWO baggage and/or little birding experience. Think about it!
Rob
Jane Turner
Well-known member
.......and there is current discussion that the multi-observer and well documented/photographed/videoed records of SBC may be in inadequate to prove that it still exists.
rob stoff
Well-known member
Same difference
Yes, there are many uncanny similarities between the Slender-billed Curlew and the Ivory-billed Woodpecker.
With the former, people like Gomphus have said, "I went up as a total sceptic" and of course they came back as believers. Exactly the same happened to Mueller and others in the swamps regarding the Ivory-billed Woodpecker.
People here have talked about the jizz of the Slender-billed Curlew compared to the Eurasian Curlew.
In the swamps they talk about the giss (general impression of size and shape) of the Ivorybill compared to the Pileated.
Comparisons are drawn between the bills of both species.
People have written copious notes until they are blue in the face (say TRE 329 and Dave_in_Michigan for the Ivorybill and Gomphus for the Slender-billed Curlew.
And just as Gomphus observed the Slender-billed Curlew for six hours, so I am reminded of the lady who observed what she claimed was an Ivory-billed Woodpecker for a whole afternoon.
And the arguments rage over both species.
Yes, there are many uncanny similarities between the Slender-billed Curlew and the Ivory-billed Woodpecker.
With the former, people like Gomphus have said, "I went up as a total sceptic" and of course they came back as believers. Exactly the same happened to Mueller and others in the swamps regarding the Ivory-billed Woodpecker.
People here have talked about the jizz of the Slender-billed Curlew compared to the Eurasian Curlew.
In the swamps they talk about the giss (general impression of size and shape) of the Ivorybill compared to the Pileated.
Comparisons are drawn between the bills of both species.
People have written copious notes until they are blue in the face (say TRE 329 and Dave_in_Michigan for the Ivorybill and Gomphus for the Slender-billed Curlew.
And just as Gomphus observed the Slender-billed Curlew for six hours, so I am reminded of the lady who observed what she claimed was an Ivory-billed Woodpecker for a whole afternoon.
And the arguments rage over both species.
Sidewinder
Well-known member
How important is woodpecker body size to flight speed and flap rate? One way of looking at it is to consider the coefficients of determination (r-squared) between these variables, which explain the proportion of variance accounted for in one variable by another. From Fig. 9 of Tobalski (1996), a correlation of r = 0.90 was determined for the relationship between body mass of five woodpecker species (Lewis' Woodpecker excluded) and wingbeat frequency for the flapping phase (if I'm interpreting his methods right) of flap-bounding flight. When squared, this value suggests that body mass explains 81% of the varaiation in mean flap rate values of the species studied. Similarly, the correlation (r = 0.84) between body mass and flight speed suggests that body mass explains 71% of the variation in mean flight speed values of the species studied.
These values (81% for wingbeat frequency, 71% for flight speed) give plenty of wriggle room for unaccounted sources of variance, which can be many (some of which are described in the article, and Mike Collins touches on these as well). With inclusion of Lewis' Woodpecker, the associations with body mass become considerably weaker (71% and a measly 7%, respectively; the r values I converted to r-squared are from the text, p. 163). But also bear in mind that a standard often used for comparative studies is to treat genus as the unit of replication, not species; and Tobalski includes two Picoides species, which might strengthen the associations he reported. Clearly, body size has some but limited explanatory power for the variables of interest.
So just where does the IBWO fit into this picture? This remains a matter of pure conjecture (the real point that Louis Bevier is trying to get across). Some want us to believe the IBWO flaps (and flies) faster than the PIWO, others want us to believe the IBWO flaps slower, and a more realistic possibility would be that there is some overlap. Anecdotal reports from historical sources are a tad bit contradictory on this issue. Tanner's audio recording does not provide a definitive answer, nor do the Collins, Nolin, or Bevier videos, even when considered in light of Tobalske's studies. Bevier is certainly correct in pointing out the sample size limitations for the PIWO data in Tobalske's published studies.
Can the blurry bird in Collins' most recent video be identified? Eventually, it may be to some degree of satisfaction by most individuals. The blurry quality notwithstanding (due to autofocus locking onto branches in the foreground, as he has indicated; give the guy a break), there may be sufficient evidence to rule out (or in) PIWO and other alternative bird species, but we won't know this for some while. For those who remain highly skeptical, consider the prevailing view of others in your camp toward the fuzzy Luneau video, as many are now convinced the bird's ID can be positively established as a PIWO. (I personally don't think the Luneau bird can be identified with certainty; I throw up my hands.) The odds that Collins has videotaped an IBWO woodpecker are vanishingly small, with the likelihood of a firm identification being smaller yet. But I'm willing to sit back and see what transpires before rushing to judgement. By now, I would imagine that plenty of useful PIWO flight videos have become available for analysis to shed light on the birds captured in the Luneau and Collins videos. Perhaps some of this material is already in the hands of Tobalske; who knows? I'm surprised that Collins himself hasn't accumulated a substantial library of his own material. Surely Cornell has a huge set of videos by now. Or is it really that difficult to get this kind of footage?
These values (81% for wingbeat frequency, 71% for flight speed) give plenty of wriggle room for unaccounted sources of variance, which can be many (some of which are described in the article, and Mike Collins touches on these as well). With inclusion of Lewis' Woodpecker, the associations with body mass become considerably weaker (71% and a measly 7%, respectively; the r values I converted to r-squared are from the text, p. 163). But also bear in mind that a standard often used for comparative studies is to treat genus as the unit of replication, not species; and Tobalski includes two Picoides species, which might strengthen the associations he reported. Clearly, body size has some but limited explanatory power for the variables of interest.
So just where does the IBWO fit into this picture? This remains a matter of pure conjecture (the real point that Louis Bevier is trying to get across). Some want us to believe the IBWO flaps (and flies) faster than the PIWO, others want us to believe the IBWO flaps slower, and a more realistic possibility would be that there is some overlap. Anecdotal reports from historical sources are a tad bit contradictory on this issue. Tanner's audio recording does not provide a definitive answer, nor do the Collins, Nolin, or Bevier videos, even when considered in light of Tobalske's studies. Bevier is certainly correct in pointing out the sample size limitations for the PIWO data in Tobalske's published studies.
Can the blurry bird in Collins' most recent video be identified? Eventually, it may be to some degree of satisfaction by most individuals. The blurry quality notwithstanding (due to autofocus locking onto branches in the foreground, as he has indicated; give the guy a break), there may be sufficient evidence to rule out (or in) PIWO and other alternative bird species, but we won't know this for some while. For those who remain highly skeptical, consider the prevailing view of others in your camp toward the fuzzy Luneau video, as many are now convinced the bird's ID can be positively established as a PIWO. (I personally don't think the Luneau bird can be identified with certainty; I throw up my hands.) The odds that Collins has videotaped an IBWO woodpecker are vanishingly small, with the likelihood of a firm identification being smaller yet. But I'm willing to sit back and see what transpires before rushing to judgement. By now, I would imagine that plenty of useful PIWO flight videos have become available for analysis to shed light on the birds captured in the Luneau and Collins videos. Perhaps some of this material is already in the hands of Tobalske; who knows? I'm surprised that Collins himself hasn't accumulated a substantial library of his own material. Surely Cornell has a huge set of videos by now. Or is it really that difficult to get this kind of footage?
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rob stoff
Well-known member
sparrowbirder
Well-known member
Just wondering in these heady times of splitting as opposed to lumping,could it be possible that the Cuban IBW could actually be a different species,if based on todays DNA way of doing things,after all didnt they frequent a totally different habitat,different call,and size differences,not sure if any research has been done on this or if any specimens exist of cuban IBW to obtain any DNA,could be the world lost 2 species as opposed to 1 (sorry ,just thought id complicate things even further)....
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