Why aren't pheasants will-o-the-wisps?

I think this is one of the weakest Ivory-bill arguments (from "The Grail Bird", page 248):

[John Fitzpatrick] also suggested that perhaps during the years when the birds were hunted extensively by collectors, only the quietest and wariest individuals in a few remnant forests survived to pass on their genes to future generations. This could explain why it is so difficult to find an ivory-bill and record its calls. Perhaps all the noisy and approachable ones were killed off a century ago.

I thought about this argument on a recent pheasant hunt. The pheasants in this area are generally sparse, and they've faced hunting pressure for many years. You could argue that the most approachable pheasants were killed off each year. However, the pheasants have not evolved into will-o-the-wisps that are impossible to shoot or see well.

I completely agree that many birds respond to hunting pressure by becoming more wary. The fallacy here is assuming that the Ivory-bill just continued to become more and more wary until it became unphotographable. In world history, I don't know of any bird species that has become remotely as wary as the postulated Ivory-bill. However, I think the "will-o-the-wisp" theory is necessary to explain how the bird could be seen maybe 18 times in a small area, while not being definitively photographed for 60+ years.

Tanner's book does contain this passage on page 63:

Arthur T. Wayne wrote in his field catalogue a note under April 22, 1892: "I saw and heard four Ivory-bills the day before in California Swamp, but could not get a shot as they were too wild, and couldn't be approached nearer than 300 or 400 yards." This was in an area where several Ivory-bills had been shot, and these birds could have become wary from shooting. The fact that they were pursued so constantly and avidly by collectors is probably the reason for the wary reputation of the bird".

In my own experience, Ivory-bills have not been particularly shy, certainly not noticeably more wary and wild than the Pileated Woodpecker.

In my reading, I don't recall any old-timer describing warier Ivory-bills than Arthur T. Wayne did above. Yet even in his extreme case of avidly hunted birds, collectors got close enough to the Ivory-bills to shoot several of them, and even the remaining birds let one person get close enough to see and hear four Ivory-bills in a single day.