I looked for a couple of seconds and then quickly moved closer hoping to sit down to study and sketch this rare find, only to discover that it was gone. Not only was the shrike gone, I couldn't even find the post it had been on! In place of both was a Great Egret calmly hunting the grassy edge of a pond.
Such is the power of suggestion. I thought I might be rewarded that morning with a sighting of a Loggerhead Shrike, and I managed to create the vision I desired out of the pattern of shadows on a Great Egret, complete with dark mask, long tail, and the right shape and posture.
If the situation was different and I was only able to see it from a distance for those first few seconds, it's very possible that I would have convinced myself that what I had seen was real and that I would have reported seeing a Loggerhead Shrike. And if anyone had questioned it I would have said I was absolutely certain. After all, I was an experienced observer and I saw multiple diagnostic field marks. What else could it have been?
This is the fundamental problem with all of the recent Ivory-billed Woodpecker sightings. Claims of certainty and lists of diagnostic field marks are simply not as meaningful when they are based on such brief views.
Proponents still emphasize the number of sightings and the fact that some auditory and visual encounters are clustered. They ask "What are the chances that all of those people were mistaken?" Referring to one of his own brief sightings, Geoffrey Hill asks "What are the chances that just as I was misidentifying a Pileated Woodpecker as an Ivory-billed Woodpecker, I would hear another pileated give a double-knock?"
First of all, these questions are spurious and attempt to shift the burden of proof to the skeptics. It is not up to the skeptics to show how all observers could be mistaken. The simple answer is "Yes, that is possible." There is no proof and whether these observations are more likely to be correct or incorrect is simply a debate over percentages.
I would argue that the chances are very good that one misidentification led to another, since these events are not independent. Here's a possible scenario:
An observer hoping to see an Ivory-billed has an ambiguous view of a bird flying away. In the moments after, while processing the flickering black-and-white pattern of the wings and while most susceptible to suggestion, a single double-knock-like sound is heard. The sound (even though it too was ambiguous and was clearly not produced by the bird that flew away) helps cross a decision threshold - that Ivory-billed is likely, that the white really did seem to be on the trailing edge of the wings, and that the bird that just flew away must have been an Ivory-billed.
That decision in turn influences the perception of the double-knock-like sound, which then seems less ambiguous and "must have been" a second Ivory-billed. And as the observer reconstructs memories of the event and adds other subtle impressions to support the identification ("that was no Pileated Woodpecker!"), a circular reinforcement occurs. The retrospective perception of the wing pattern and sound actually change as positive elements are replayed and negatives ignored. The more certain the wing pattern seems, the better the double-knock sounds, which reinforces the interpretation of the wing pattern, and so on.
This may not be exactly what happened in this case, but all of these effects are well-documented in psychological research.
No intentional falsification or fabrication is needed, simply a subconscious selection of evidence supporting the favored conclusion, and a subconscious omission of refuting evidence. This generates false confidence. Once the perception is formed and "confirmed" it becomes nearly immune to question or revision. Claims of certainty and "multiple field marks seen" must be judged in the context of the situation. Longer and better views of a bird require less interpretation and give the observer more information and more opportunity to correct mistakes. Views as poor as all of the reported Ivory-billed sightings are far from certain.
This does not mean they should be ignored, and they have not been ignored. The reported sightings have inspired and guided massive search and conservation efforts in the last three years and before. Sightings should continue to be carefully reviewed and followed-up, but we have to be realistic about the strength of those sight records. If unprecedented search efforts fail to find what a few people glimpsed three years ago, it might indicate that those observers were mistaken.