The first rule about the Cornell Ivory-billed Woodpecker Search is you do not talk about the Ivory-billed Woodpecker Search. The second rule about the Cornell Ivory-billed Woodpecker Search is you do not talk about the Ivory-billed Woodpecker Search...Now, of course you wouldn't want people posting GPS coordinates on the net if they ever found an Ivory-bill roosting location. However, putting a lid on all speech seems excessive.
Regarding Cornell's claimed Ivory-bill rediscovery, the "cat is pretty far out of the bag" already. After all, Cornell has already published a detailed map (North American Birds, Dec '04-Feb '05, page 199) showing exactly where each claimed sighting occurred.
If you put excessive secrecy measures in place at this point, people might justifiably wonder whether you have something to hide.
Some of the following could conceivably be among the "hidden items":
1. Original field notes, sketches and videotaped interviews describing all possible sightings
2. Information about (and pictures of) abnormal Pileateds in the area
3. The Imperial Woodpecker video
4. Candid observations about how much of the area has been searched, and how "inaccessible" it truly is
5. Information that privately, not all searchers may leave Arkansas as "true believers"
6. Information about the "dead branch"/"six-pixel ivory-bill" in the Luneau video
7. Maybe Cornell has video that shows a Pileated briefly flying at greater than 7.5 flaps/sec
8. Maybe Cornell has video of a fleeing known Pileated that looks uncomfortably similar to the Luneau bird
9. Information about Pileated Woodpeckers observed doing double-raps in the search area
10. Information about the true birding experience level of some of the observers
Right now, many skeptics feel that Cornell is releasing information selectively (heavily favoring information that can be spun in favor of the Ivory-bill rediscovery story).
In my opinion, good science demands that the countervailing information also be released.