Layer position changes when attaching it to a path.

[Reindeer]

I am trying to attach a bird to a circular path so I can make it fly round an round. This bird has some animation prior to this part (he flies in, rests on a tree branch an then I want him to fly again to begin a circular loop).
I created a vector layer beneath the bird layer (which is a bone layer) and drew an oval path. Then I went back on the bird layer, clicked on the path tool and pointed to my starting position on the oval. Here's where stuff goes wrong: I get a path position keyframe on the timeline but the whole bird layer totally changes position, thereby including all the animation prior to this point. If I go back to the beginning, now he flies in from another position and doesn't rest on the branch anymore. He's off register.
I've tried everything in my (still raw) knowledge, including unchecking Relative Keryframes and enclosing the bird layer in a group (thinking this would trick the software into giving the bird a new reference point). Nothing doing, as soon as I click on the path, the whole thing goes out of whack.
I'm sure it's some obvious thing, I suspect the Origin point has something to do with it but as of now I'm stuck. Mumble....

[slowtiger]

Try to reset the origin of the topmost bird layer in frame 0 (cmd-0), correct the bird's position in frame 1, and go on from there. Don't put it into another group.

[Reindeer]

I tried what you suggested, thank you. It unfortunately didn't work, but I'll iron it out: I put the origin of the bird on its feet (which is the point of contact I want with the oval path) on frame 0. This of course changed the rest of the animation's positions, so I selected all Keyframes and turned on Relative Keyframing (this was not in your suggestion but I figured out I'd need it to move all positions at once) and moved him back to register.
I then jumped to my oval path situation and tried attaching the bird's feet to the path (with the new Origin) but no, it jumps again and still moves all previous keyframes.
I may have to override this problem by duplicating the layer and continuing the animation by switching to the old layer (with visibility off for the old one and on for the new one). I don't like this solution because it creates more layers and divides up an action in two different segments but I can't see any other one in sight.

[Reindeer]

On the side, one strange thing I notice in using paths is that attaching a layer to a path will work only a couple of times. Meaning that undoing will not let you redo forever.
Say, you attach to the path and you don't like the way it worked. So you do Undo and try again. Still not right, so you Undo a second time. But now, after two undos, trying to attach will not work anymore. I mean it just won't do anything, I click on the path but no kayframe is created. The only way to go on is to create a new path vector layer.
Weird, that. It kind of looks like a bug.

[synthsin75]

Changing the layer's origin will change any animated keys if layer scale or rotation have been changed.

You can undo and redo follow path down the tineline so long as there is a frame zero 'connection' to that path.

[Reindeer]

[quote="synthsin75"]Changing the layer's origin will change any animated keys if layer scale or rotation have been changed. /quote]

Hi, thank you. Yes, I understand that changing the Origin will change keys. But here I'm not touching the origin. What baffles me is that the Layer moves when I use the Follow Path tool. As soon as I click on the first position on the path, everything shifts. This happens independently from where the origin is placed.