Supplemental material for “Putative audio recordings of the Ivory-billed Woodpecker (Campephilus principalis),” J. Acoust. Soc. Am. 129 (3), March 2011.


Audio Files

Audio S1. High-pitched calls that were recorded during the first two minutes of the 2006 video. The recording also contains the calls of two American Crows that appeared to be harassing the bird.

Audio S2. A putative double knock from the 2008 video, which is immediately followed by a digitally superimposed putative double knock that was recorded in Florida (Ref. 6). The brief time interval between knocks is about the same for these recordings.


Movie Files

Movie S1. Rared-back posture, large bill, and unusual movements of the large woodpecker in the 2006 video. The movie is sampled at 30 frames per second and plays at full speed. It has been deinterlaced, cropped, and enlarged. Individual frames have been scaled and translated in order to remove the effects of camera movement and zooming.

Movie S2. Flapping leap by the large woodpecker in the 2006 video. The movie is sampled at 60 frames per second and plays at half speed. It has been deinterlaced, cropped, and enlarged.

Movie S3. Takeoff with ponderous and heavy flaps by the large woodpecker in the 2006 video. The movie is sampled at 60 frames per second and plays at half speed. It has been deinterlaced, cropped, and enlarged. Individual frames have been scaled and translated in order to remove the effects of camera movement and zooming.

Movie S4. Video of the encounter on February 20, 2006, from just after the bird was observed until the flapping leap more than ten minutes later. This footage documents the author turning the kayak, drifting back down the bayou while tracking the movements of the high-pitched calls, and then backing the kayak into an observation position on the opposite side of the bayou. Note that the field of view was nearly centered on the location of the bird just before the camera zoomed in on the bird a little over 10 minutes into the movie. Resolution has been reduced in this movie, which is not intended to show details of the bird.

Movie S5. The bird approaching the observation tree in the 2008 video. Both the bird and its reflection from the still surface of the bayou are visible. The bird has a distinctive flap style in which the wings are folded closed in the middle of the upstroke. The movie is sampled at 60 frames per second and plays at half speed. It has been deinterlaced and compressed into mp4 format.

Movie S6. The bird continuing up the bayou beyond the observation tree in the 2008 video. Both the bird and its reflection from the still surface of the bayou are visible. In frame 28, the wings appear to have a high aspect ratio in the reflection of the bird off the water. In frames 59 through 68, large white patches are visible on the dorsal surfaces of the wings (dark plumage apparently blends in with the dark mud in the background). In frames 96 through 117, the wings can be seen folding closed in the reflection of the bird off the water. The movie is sampled at 60 frames per second and plays at half speed. It has been deinterlaced and compressed into mp4 format.

Movie S7. A putative double knock in the 2008 video. Immediately after the putative double knock, which occurs about 24 s into the movie, the camera pans toward the direction in which the bird was detected about 101 s into the movie. Note the overcast sky, the still surface of the bayou, and the apparent lack of wind (strands of moss appear to move only when the author moves). The movie plays at full speed and is sampled at 30 frames per second. Resolution has been reduced in this movie, which is not intended to show details of the bird.


Supplemental Figures



Figure S1. The wings of the bird in the 2008 video. The top row shows two consecutive frames in which the wings are extended and then folded against the body. The other image in the top row is a photo obtained by James Tanner in 1939 of an Ivory-billed Woodpecker in flight with the wings folded against the body (this photo is in the possession of the U.S. Fish and Wildlife Service). The second row shows the reflection of the bird off the water in three consecutive frames that provide a different perspective on the folding of the wings against the body. The third row shows the reflection of the bird off the water in two consecutive frames in which the wings appear to be narrow. The other image in the third row (which was obtained by the author) illustrates the relatively broad wings of a Pileated Woodpecker. The bottom row shows three consecutive frames in which large white patches are visible on the dorsal surfaces of the wings (dark plumage apparently blends in with the dark mud in the background). The white patches cannot correspond to solar specular reflection since the video was obtained on an overcast morning. The center image appears to show white on the back/neck, which is consistent with the dorsal stripes that were observed in the field.



Figure S2. Wingspan of the bird in the 2008 video. The tips of the fully extended wings are poorly resolved when the bird was flying toward the camera; they are well resolved in a reflection just before the bird passed below the observation tree, but the reflected image corresponds to a position below the surface. An approximate bound on the wingspan was obtained using frames from both parts of the video. An image from the video (A) shows the bird with the wings partially extended. A reference image obtained from the same position in the observation tree (B) was rotated and scaled in order to line up the two large trees, the fallen tree and small tree behind the two large trees, and other objects (a small branch was removed from the observation tree before obtaining the reference image). The horizontal position of a stake with 24-inch crossbars was determined using the mid-point between the direct and reflected images of the bird, which corresponds approximately to the projection of the position of the bird onto the surface. The top crossbar, which is just below the position of the bird, was used to obtain the black length scale that appears below the bird in A. The images in C and D show reflections of the bird in consecutive frames that were scaled by assuming that the partially extended wings in D are extended by about the same amount as in A. This comparison suggests that the wingspan is greater than 24 inches. There is a significant non-vertical component to the bending of the wings in D and in the photo of an Ivory-billed Woodpecker in E that was obtained by James Tanner in 1939 (this photo is in the possession of the U.S. Fish and Wildlife Service). This factor would make it difficult to obtain a reliable estimate of the wingspan only from A.



Figure S3. Position of the bird as it passed the observation tree in the 2008 video. In an image from the video (top), arrows mark the direct (1) and reflected (2) images of the bird (difficult to see in the isolated image but easy to see when perusing the video frame by frame). In the reference image (below), an arrow marks the location of a stake (3) that was positioned near the mid-point between the direct and reflected images by lining up branches of the observation tree. Some small branches were missing and the appearance of the moss was different when the reference image was obtained.



Figure S4. Flight speed of the bird in the 2008 video. In an image from the video (right) that corresponds to 4.38 s earlier than the image in Figure S3, arrows mark the direct (1) and reflected (2) images of the bird (difficult to see in the isolated image but easy to see when perusing the video frame by frame). In the reference image (left), arrows mark the positions of stakes at 33 m (3), 51 m (4), and 66.5 m (5) from the stake that appears in Figure S3. The stakes at 33 m and 51 m correspond to published values (Ref. 12) for the minimum (7.5 m/s) and maximum (11.6 m/s) flight speeds of the Pileated Woodpecker in cruising flight. The stake at 66.5 m corresponds to a flight speed of 15.2 m/s and is at about the same distance as the mid-point between the direct and reflected images (the slight offset to the right should only have a small effect on the flight speed estimate). The image from the video was scaled and rotated using features of the large tree on the right and the reflected images of trees in the background (the slight difference in water level should only have a small effect on the flight speed estimate).



Figure S5. The 2006 (1) and 2008 (2) videos were obtained at locations that are separated by less than a kilometer along a winding bayou, which is partially hidden by trees of a relatively bright shade of green.