One of the most satisfying things a scientist can do is to predict something based on existing data and then have the prediction confirmed by new data. After obtaining video clips of an ivorybill taking short flights, I was initially puzzled by the extremely deep flaps (described as ponderous by Julie Zickefoose), which didn't seem to be in line with the classical reports of a pintail-like flight. The flaps are very deep when the bird hops across the fork and when it flies off to the left. There is also a violent flap as the bird takes off and flies through a gap in the vegetation earlier in the video. When I visited Cornell, someone mentioned that deep flaps aren't consistent with ivorybill, but then I realized that, in fact, an ivorybill must use deep flaps on short flights and just after take-off. Since this species is relatively heavy, its relatively long and thin wings don't provide enough lift until it gains speed. After figuring this out, it dawned on me that the flaps should transition into pintail-like flaps as the bird gains speed. Jan Swart, a fellow mathematician and birder from the Czech Republic, drew my attention to the fact that Brian Rolek has observed this behavior (as reported in his field notes for February 1, 2006, but not made public until a few months ago).
Some of our members have taken great pains over the years to examine bark scalings and feeding cavities in order to shed more light on the species' feeding habits. Tanner et al wrote a great deal on insect species and breeding behaviour. This thread should provide a format to discuss and key in on IBWO diet throughout its range as well as flight patterns and general behavior.
"After obtaining video clips of an ivorybill taking short flights, I was initially puzzled by the extremely deep flaps (described as ponderous by Julie Zickefoose), which didn't seem to be in line with the classical reports of a pintail-like flight."
Cinc:
Do you happen to have a link to Zickfoose account of wing size and any other valuable information that she has on the species?
Do you happen to have a link to Zickfoose account of wing size and any other valuable information that she has on the species?
I think she basically just has all that information in her mind's eye, having painted the cover of Jackson's book, the cover of an issue of The Auk, etc.
On December 31, 2005 I found a dead young tree [some type of pine?], likely worked on by a large woodpecker, in a swampy area at Lake Waccamaw State Park, NC [photos A and B in the attachment]. I estimated the tree to be about 6in DBH with the scaling starting about 8ft above ground and extending for about 5ft. I couldn't reach the tree to measure it though. The close-up photos were obtained by digiscoping.
Photo C shows a bark chip still attached to the trunk. The chip was produced by a single glancing blow as can be deduced from the position of the single beak mark at the top. If my size estimate for the trunk is accurate then the chip is at least 3 inches long. Photo D is a close-up showing shallow pits from where, presumably, the bird removed beetle larva that were boring under the bark. Photo E is a close-up showing fibers of the bark and stem dislodged by the bird.
A few things struck me about this example of woodpecker feeding sign. The first is
that I had never before encountered anything like this. The second is the similarity, specially
of the details in Photos C and E, with a photo of IBWO work in the article by Allen & Kellog [[The Auk, Vol. 54, April 1937, pp. 164-184; see bottom photo in Plate 11, specially the pine in the right side, background]. The third thing is the similarity of the work in Photo D with some of the examples of woodpecker work found in the Choctawhatchee search which Prof. Hill suspects were made by IBWOs.
Last edited by Dacol : 11-17-2006 at 11:17 AM.
Reason: posting mishap
This sign is indeed quite interesting. Although it is of course a subjective impression, the bark looks tight to me. I encourage everyone to try to get measurements of bark adhesion on scaled trees. The Cabela's digital scale is only $20, but I imagine most any fish scale would do the job. A picture hanging hook can be slipped under the bark and pulled with the fish scale. To match the methods of Hill et al., pull the bark until a clearance of 1 cm is achieved.
[quote=Dacol;40]On December 31, 2005 I found a dead young tree [some type of pine?], likely worked on by a large woodpecker, in a swampy area at Lake Waccamaw State Park, NC [photos A and B in the attachment]. I estimated the tree to be about 6in DBH with the scaling starting about 8ft above ground and extending for about 5ft. I couldn't reach the tree to measure it though. The close-up photos were obtained by digiscoping.
Dacol this is a wonderful example of how digiscoping can provide a great tool for the researcher. Intriguing photos and I was curious what primary type of habitat you were in in Lake Waccamaw SP. Also how large is the Park with regards to potential IBWO useage?
I cant help but think that a lot of information is going to be revealed in the future in areas that would have been not even considered IBWO habitat as little as 3 years ago.
Thanks again for the post and its great to see that the thumbnail image feature works on the forum. Yours is a first and I hope one of many to come!
I have a few more thoughts to add about deep flaps.
There is an exception in which an ivorybill doesn't need to use deep flaps on take-off. If it drops out of a tree and uses gravity to accelerate, it doesn't need to use deep flaps. This is apparently what happened in the famous photo of an ivorybill leaving a nest cavity on outstretched wings and viewed from below.
The massive body and long, thin wings also make landing awkward. There are classical accounts of ivorybills swooping up gracefully to land. I'm pretty sure that I observed this on November 18, 2005, which was my first possible sighting. The bird flew across the Pearl from the Mississippi side and swooped up without flapping just before landing. It then apparently moved immediately to the back side of the tree. I have never heard this discussed before, but an ivorybill can also land by fluttering to decelerate. I observed this during my sighting on October 21, 2006. The bird landed high in a tree without swooping upward and vigorously fluttered its outstretched wings in order to decelerate and make adjustments in its position and orientation. I saw the bird from behind early on a clear morning with the sun to my back. It was very dramatic to see the motion of the white trailing edges of the fluttering wings.
The ivorybill in my video kept an eye on me for more than ten minutes after it flushed. During this time, it took two short hop-flights and spent a lot of time peaking around at me from behind its perch. I don't understand why it made the hop-flights. Perhaps it wanted to get a better look at me than it could get by peaking around. These hop-flights were only a fraction of a second, apparently because the bird wanted to remain hidden as much as possible. The use of hop-flights might be a habit of the particular bird in my video. If other ivorybills do this, however, it might be a useful way to find ivorybills in a way that they can be easily photographed. Most of my sightings have been of birds flushed from near the ground that immediately took off and were out of view within a few seconds. The hop-flights occurred high in distant trees. If I had actually seen the bird, I may have gotten a good photo because the bird remained in the tree (for at least 90 seconds in one case). I have recently been keeping my eyes open for hop-flights. Without focusing on any particular point, I concentrate on the treetops in the distance. If something does one of these hop-flights in the distance and then disappears behind a branch, there is a good chance it's an ivorybill. This hop-flight behavior suggests that the ivorybill is a very wily bird, perhaps as intelligent as a corvid.
I would speculate that these "hops" serve to help each bird of the pair locate the other before they leave the area. It stands to reason that these birds, with their tendency to form strong pair bonds and cover large areas, are very visually attuned to each other. Tanner noted that "occasionally they traveled quite silently, following each other by sight through several flights."
The ivorybill in my video kept an eye on me for more than ten minutes after it flushed. During this time, it took two short hop-flights and spent a lot of time peaking around at me from behind its perch. I don't understand why it made the hop-flights. Perhaps it wanted to get a better look at me than it could get by peaking around. These hop-flights were only a fraction of a second, apparently because the bird wanted to remain hidden as much as possible. The use of hop-flights might be a habit of the particular bird in my video. If other ivorybills do this, however, it might be a useful way to find ivorybills in a way that they can be easily photographed. Most of my sightings have been of birds flushed from near the ground that immediately took off and were out of view within a few seconds. The hop-flights occurred high in distant trees. If I had actually seen the bird, I may have gotten a good photo because the bird remained in the tree (for at least 90 seconds in one case). I have recently been keeping my eyes open for hop-flights. Without focusing on any particular point, I concentrate on the treetops in the distance. If something does one of these hop-flights in the distance and then disappears behind a branch, there is a good chance it's an ivorybill. This hop-flight behavior suggests that the ivorybill is a very wily bird, perhaps as intelligent as a corvid.
Cinc: my theory on this is simply that these are birds that are highly agitated at seeing a "predator" and actually torn between fleeing the area and staying put. So in quick summary I compare this to any bird species that has located danger and is both facinated and fearful. Perhaps even the smaller woodpecker species do this but since they are small their "hopping" from one tree to another may be less spectacular.
I am extremely interested in learning if any historical data describes an actualy predator/prey interaction with the ivory-bill. Afterall it doesnt seem like the ivory-bills short heavy flight on long wings leads itself to being mobile quickly to avoid avian predators.
...I was curious what primary type of habitat you were in in Lake Waccamaw SP. Also how large is the Park with regards to potential IBWO useage?
The photos were taken at boundary of a large swampy area and the sandy pine ridge that makes up most of the southern and eastern rim of the lake. The state park is small, a bit less than 2000 acres, most of it in the form of pine groves with dense understory on a sand ridge, typical of the pocosin formations of the Carolinas, the southern edge of the park is within a large area (~20000 acres) with bald cypress-tupelo swamps and hardwood bottomlands. There is also a large swampy area to the north, of the order of 10000 acres, which is a NC WMA [Gamelands]. The south edge of the park includes the headwaters of the Waccamaw River which drains the large lake. Beyond the headwaters bottomland the river has at least ribbons of forest along it and as it approaches the NC-SC border the amount of forest increases substantially, eventually the river joins Winyah Bay in SC and thus it connects to other great rivers such as the Great and Little Pee-Dee and the Lumber. Soon after the headwater's bottomland narrows down the Waccamaw is joined by Jennifer Creek which drains swampland to the east, This creek is actually larger than the Waccamaw at the junction and traverses another large NC Gamelands and one of its tributaries, Driving Creek, originates in the large Nature Conservancy Green Swamp preserve (~15000 acres, mostly long-leaf pine savannah with swamps mixed in). The rest of the great Green Swamp has been converted to pine plantations. Those pine plantations while not providing great habitat do provide cover as they tend to be managed in such a way as there are aways trees around. It was near Rt 211, between the TNC property and Lake Waccamaw that 2 fisherman reported to Cornell having seen a pair of IBWOs flying along a forested creek.
I have a few more thoughts to add about deep flaps.
I observed this during my sighting on October 21, 2006. The bird landed high in a tree without swooping upward and vigorously fluttered its outstretched wings in order to decelerate and make adjustments in its position and orientation. .
Cinc for the benefit of others would you be so kind as to list some data on wingspread length? Also having such long wings and IBWO movements would seem from viewpoint to put the bird at a slight disadvantage as far as avoiding predators. What do we know about predation? Thanks for your imput here as always!
Cinc for the benefit of others would you be so kind as to list some data on wingspread length? Also having such long wings and IBWO movements would seem from viewpoint to put the bird at a slight disadvantage as far as avoiding predators. What do we know about predation?
I'm in the Pearl and don't have access to reference material. Perhaps someone else can provide this data. I don't believe the ivorybill is particularly vulnerable to predators.
It would be nice to have an estimate of the width of the chisel mark in C. It looks like an ivorybill left an impression of its bill in plaster of paris.
After studying the video, it is my impression that the purpose of hop-flights is to get a better view of a threat either while in the air or from a new position. Before the hop-flight at the 10.5 minute mark in the video, the bird hid behind the branch and repeatedly peaked around at me, briefly rotated into view, and climbed up to a higher vantage point. It was clearly watching me, probably had a partially obstructed view of me, and seemed to be adjusting its position to get a better view. After the hop-flight, the bird remained in the new position for nearly a minute before flying off to the left. The other hop-flight at the 2 minute mark was similar, but you can't see what it does before and after.
On the CLO web site the aspect ratio of the pileated wing is given as 1.4-1.9, taken from video frames of birds with outstretched wings. There is as yet only one clear photo showing the aspect ratio of an ivory-bill wing. This was estimated at 2.4.
As far as predation goes, Tanner saw no indication of predation. Lamb's contacts in Cuba told him firmly that Cuban crows attacked ivory-bill nests, although he never saw this himself.
There is as yet only one clear photo showing the aspect ratio of an ivory-bill wing. This was estimated at 2.4.
Are you referring to the photo from the 1930s that shows the bird from below as it flies from the nest? That is my favorite ivorybill photo. Frame 04 in the "Wing length, shape, dynamics" section here should give a pretty good estimate of aspect ratio. It appears to be greater than 2.0, but it's hard to be sure since the wing may not be orthogonal to the line of sight. This is the first thing that jumped out at me about this video.
It would be nice to have an estimate of the width of the chisel mark in C. It looks like an ivorybill left an impression of its bill in plaster of paris.
A totally speculative answer as I couldn't measure the diameter of the tree.
If the diameter is 6in as I guessed then (see attached figure) the length of the red line is (assumed) 6in = 15.2cm, the length of the blue line is 2.1in = 5.3cm and the length of the green line is .46in = 1.2cm. The lengths of the bloe and green lines overestimate a bit the actual dimensions of the marks.
In image C, I see what appears to be a massive chisel mark that is oriented vertically. A mirror image of this mark appears in the piece of bark that is dangling below. If that really is a chisel mark, then I would bet the farm that it's ivorybill work.
That is my favorite ivorybill photo. Frame 04 in the "Wing length, shape, dynamics" section here should give a pretty good estimate of aspect ratio. It appears to be greater than 2.0, but it's hard to be sure since the wing may not be orthogonal to the line of sight. This is the first thing that jumped out at me about this video.
Cinc this footage is amazing. For those of us who only dream of seeing an IBWO I can only say I would be high for days having had this opportunity! Thanks for sharing this link to your website!
In image C, I see what appears to be a massive chisel mark that is oriented vertically. A mirror image of this mark appears in the piece of bark that is dangling below. If that really is a chisel mark, then I would bet the farm that it's ivorybill work.
It is hard to tell whether there is a vertical blow. My initial impression was that the first strike at top left was quite powerful and displaced the piece of bark. Starting form the top there is the blow indicated by the blue arrow. It seems [specially in the original, higher resolution, picture] that there are two other blows, apparently of lesser intensity, but the same orientation as the blue arrow. These two blows seemed to uncover two small pits. Below the two pits one sees more clearly what you interpret as a chisel-like mark. Eye-balling it, at the widest it seems to be comparable to the green line and a bit longer than the blue line. Thus at least one other interpretation is possible: first blow along the blue line loosens the top of the bark chip, a second blow, downward and nearly vertical, flips the chip off the trunk. The weaker blows, more or less parallel to the blue line, uncover whatever it was that the woodpecker was looking for.
Dalcio
Last edited by Dacol : 11-21-2006 at 06:08 AM.
Reason: typos
After studying the video, it is my impression that the purpose of hop-flights is to get a better view of a threat either while in the air or from a new position. Before the hop-flight at the 10.5 minute mark in the video, the bird hid behind the branch and repeatedly peaked around at me, briefly rotated into view, and climbed up to a higher vantage point. It was clearly watching me, probably had a partially obstructed view of me, and seemed to be adjusting its position to get a better view. After the hop-flight, the bird remained in the new position for nearly a minute before flying off to the left. The other hop-flight at the 2 minute mark was similar, but you can't see what it does before and after.
cinc do we know if this kind of "hop-flight" behavior is documented anywhere in historical literature? Simply curious ...
cinc do we know if this kind of "hop-flight" behavior is documented anywhere in historical literature?
I'm not aware of any documentation of this type of behavior. It probably wasn't observed in the Singer Tract since those birds were acclimated to humans. On the other hand, I'm sure that the transition from deep flaps to pintail-like flaps was observed many times, but such a detail probably didn't seem worth documenting. I would bet that any of the researchers in the Singer Tract would immediately identify the bird in my video based on the deep flaps and other clues that weren't documented. As I have said before, studying the ivorybill is going to be like studying a new species.
three that I have seen have "hopped" around the tree they were on or to a nearby tree.... sounding nearly like a tree rat jumping from tree to tree -
after watching nearly 40 hooded mergansers zoom by on yesterday's duck hunt - I am amazed at how much they look like (wing beat and flight pattern wise) like an IBWO..
__________________
"the first time you quit it's hard, the second time a little easier and heck son the third time you don't even think about it"
The ivorybill in my video kept an eye on me for more than ten minutes after it flushed. During this time, it took two short hop-flights and spent a lot of time peaking around at me from behind its perch. I don't understand why it made the hop-flights. Perhaps it wanted to get a better look at me than it could get by peaking around. These hop-flights were only a fraction of a second, apparently because the bird wanted to remain hidden as much as possible. The use of hop-flights might be a habit of the particular bird in my video. If other ivorybills do this, however, it might be a useful way to find ivorybills in a way that they can be easily photographed. Most of my sightings have been of birds .......
I plan to come out in early January, first stop is the Pearl River, then I hope to join the volunteer group at Nokuse Plantation and assist them with measuring inaccessable roost holes with my Impulse laser and do some searching there in the big timber just to the South of Nokuse. Those trees are huge in there. I then plan to explore lower Escambia extensively, assuming I can get access and do a roost hole inventory with my laser, feeding sign search and if I am lucky also get some audio evidence or even better yet see the bird and get video evidence. How is access to Escambia?
Michael C, any advise for searching the Pearl? What about video and/or digital camera? Which model and brand is best suited for capturing the enigmatic ivorybill? Please advise......
Michael T.
Last edited by hyperion380 : 11-24-2006 at 06:38 PM.
Reason: spelling errors, condensed text, overly wordy
Ivory-bill Feeding Patterns and Behavior
Linear Mode
