Cache River area combed VERY thoroughly

Cyberthrush asked a key question here:
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...do the skeptics fully appreciate the size/vastness of the territory involved!?
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Actually, I do appreciate the size of the territory. In fact, that's one reason that I'm a skeptic--Cornell's paper says their 8-18 sightings were grouped very tightly in an area only four square kilometers in size. That's equivalent to a square that's only about 1.25 miles on a side.

I believe the area in question is near the center of this Google map. Note that the habitat near the Highway 17 crossing is really just a strip roughly one mile wide.

Once again, the question is "How could you glimpse the bird 8-18 times in such a small area, yet never get a good look, and never hear it call?". The small area where the sightings occurred was combed and recombed--please see this snippet from Cornell's paper for some details:
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Between 12 March and 10 May 2004, 30 individuals spent about 2500 party-hours surveying 15 [square kilometers] of swamp forest in the vicinity of the initial sighting. Observers wore camouflaged clothing and made slow, quiet movements or remained stationary for periods at lake edges and powerline cuts. Between 25 May and 20 December 2004, T. Barksdale spent portions of 165 days (9 to 12 hours per day) observing from a 25 m elevated boom at the forest edge. Between December 2004 and April 2005, we worked in the Cache-White-Arkansas river area with 20 full-time observers and an average of 2 additional rotating volunteers. We devoted 4750 party-hours to searching 145 [square kilometers] of forest for foraging signs and roost or nest cavities by walking global positioning system–guided parallel transects spaced 50 to 55 m apart. Cavities of suitable size were watched from 85 min prior to sunset until 10 min after sunset. Our searching was focused in areas of mature forest that contain concentrations of dead and dying trees. On 2–4 March 2005 we conducted a "saturation search" with 23 observers spaced across the 4 [square kilometer area] of forest in which all the sightings had occurred. We also used eight video-camera traps, which were placed at possible foraging sites over various intervals. Broadcast playback of ivory-billed woodpecker vocalizations was used sparingly.
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The snippet above may give you some perspective on the magnitude of the effort to date. During the "saturation search", depending on how the observers were spaced, it seems to me that it would be difficult for the bird to remain more than about 250 yards from any observer at any time. Doing some math, if 23 observers spent 12 hours/day searching for 3 days, that would be 828 total search hours. If Cornell spent 20,000 total hours searching, that would be equivalent to 24 instances of these all-day, 23-person, 3-day searches.

The search team hasn't yet obtained a single good look at an Ivory-bill, but it seems that they've already made a truly massive effort.