Objective: Obtain irrefutable evidence

Here is a notable paragraph from a recent Washington Post article (the bold font is mine):

But scientists such as Cornell's Ron Rohrbaugh, who directs the ivory-billed woodpecker research project, have a more urgent task. Rohrbaugh lists it at the top of his PowerPoint presentation on the group's objectives: "Relocate the bird and obtain irrefutable evidence."

Isn't that an admission that we don't already have irrefutable evidence? If we don't have irrefutable evidence now, then I don't understand the "dead solid confirmed" announcement in April, with the resultant massive media splash that moved many to tears...

Shouldn't these T-shirts say something like "Possibly found!"?