Uh... No, the maximum range can span across areas. I had mine sense when I was in the Sea of Despair, when the diamond was along the river north of the wasteland.

My apologies - let me rephrase. If it is not within 25 rooms, but it is within the local area, it will show as such. Checking for 25 rooms trumps local area, though.

Ah, gotcha. Does that mean that the only time a feather will twitch is when it is outside the 25 room radius but within the area? That'd explain why my feather turned and never twitched, while others twitched before it turned.

That is correct.

I suspected, but couldn't be sure. That'll be highly helpful for locating it in UV. Thank you for the notification.

So that's what that means.

The Hifare Hills scythe room. And even when standing in the room right above it where the puzzle is, the feather only unfolded/twitched.

For something that has do be done 21 times in the month, that seems excessively frustrating. Time for bed.

That's why this knowledge is so useful. With a twitch, you know that the item is in the area. And if it is a small area, you'll know that it is in a room that you usually have to quest open. Sure, questing open rooms can be a bit lame, especially if you don't know how to open it, but at least you know that you're in the correct location.

The only one that didn't make sense for the feather that made me wonder if it might be buggy is Faragan's feather twitched in Illwater Lake and his feather was on Spectre Isle. That really made me want to punch someone in the face by the time I finished it.

There's a pathway straight down from the Sea of Despair into Illwater lake. I think it's one-way only though.

it's not, it's the taerin passages

Yes... it goes through the Taerin passages and ends up in the Illwater lake. Just because it passes through another area first doesn't that change the fact that you can go down from the Sea of Despair into Illwater lake.

A glittering snow feather floats into the air and spins about energetically. this mean I'm close?

Yeah, it's the second-to-closest message (aside from the message of it being found).

I meant it's not one way, not that it didn't go down from the Sea of Despair to the Illwater.

Ah. Yes, that's probably correct. I haven't used the passage in forever.

I'll relate a story to help out.
I was helping someone with a twitching feather in Zoaka. As soon as we opened sealed off lava caves, the feather went back to normal. The diamond was inside

It seems the twitching means 'path blocked'

No, the twitching means that the diamond is in the area, but cannot be reached in 25 steps. This could, of course, mean that the path is blocked, but could also mean that it's simply too far away.

Last night/this morning I covered the entire basin in a search grid with each node no farther than 20 from another and got absolutely no results. The only area I couldn't reach was Mt. Dio. If the diamonds can spawn there I will be a very sad panda.

PS: Yes, I checked the UV, too. The total search took about 3 hours, and I still don't have a diamond to show for it

Did you get different feathers at any point? A new feather has a new node (you would have to revisit areas).