I wouldn’t say a “consensus” exists on the issue. Without taking a poll, it would be hard to say what the majority of ornithologists think at this point.
I think that a lot of ornithologists thought the Arkansas records indicated there was a high probablity there was a bird or birds in the Cache Creek area. There were initially a few prominent skeptics, who became convinced once they heard the recordings of calls from the area. More recently there has been another critical article published in the Auk, the journal of the American Orinithologist’s Union, and a rebuttal published shortly after.
Some people who were originally open to the Arkansas sighting being correct have now become skeptical because of the lack of additional sightings from the area, and the failure to obtain pictures. Personally, I suspect that those sightings pertained to a wandering bird, and that they have not yet identified the area where the real population exists. This also goes for the Lousiana sighting a few years ago.
My sense is that the ornithological community would like to believe these reports. They do remain skeptical to some extent, however, since everyone is familiar with how unreliable sight records can be.
I listened to the calls and taps played by Hill at his presentation. He says the frequencies match the one known recording made in 1935. As I said, these keent calls, which sound like a flat toy-trumpet note, sound like something that a Blue Jay *could * make, but I have never heard a Blue Jay actually make such a call. Many of these calls were recorded by automatic microphones in a part of the swamp where Blue Jays were not seen by the researchers in winter, and where no more typical Blue Jay calls were recorded. So you would have to believe that Blue Jays were giving only these highly unusual calls, and not giving any of their more typical calls, for several months, while avoiding being seen by the observers. As far as the double taps go, these of course be produced by two branches knocking together, or other causes. However, because they recorded so many such taps - which sound to me like those made by other members of the genus - makes it probable that these actually were made by Ivorybills, especially since they were recorded in the same areas as the keent calls.
I have also seen the field sketches produced by various observers. Although amateurs can easily confuse Pileateds with Ivorybills, the distinction is not a difficult one for an experienced observer. It is not just one of size or proportion, or of minor color variations, but whether a prominent part of the plumage is black vs white, or black vs red. I do not think experienced observers would make such errors, unless they were outright delusional.
Individually, none of the lines of evidence are absolutely unassailable. You can find fault with any one of them, by assuming some highly unlikely circumstances (such as Blue Jays only giving unusual calls in the same area as a lot of tree limbs happen to produce double knocks and where a bunch of delusional observers are wandering around). But if you put them all together I think they add up to a very high probablity that there are Ivorybills in the area.
