Prochorus circles around the rock a few times, then dips down and dives a few meters.
I'll spont Clear Sight of the Naiad and see if I can spot anything out of the ordinary.
(Not within your capabilities when in scaup shape. Sta 1 + Intellego 5 + Aquam 0 - No voice 10 - No gestures 5 = -9)
Nothing is noticeable to Prochorus when he dives in scaup shape without the benefits of a spell.
(Oops. I have subtle magic, though, so it's just -4. I'll life-link it, should be doable right?)
(Ah, yes. I thought so but couldn't find it. Having multiple lines for the virtues makes it harder to locate stuff. Nevermind. He pulls it off, losing 2 Fatigue levels. Nothing noteworthy to be seen with the spell either.)
(Is it deep there? )
(OOC: The rock is located at the limit between deep sea and the shallower area that existed near the Danish coastline at the time. The shallow area gets wider as one moves south, but at this point it is probably 10 to 15 miles wide. So to the south and east of the rock the sea is shallow, less then 10 paces deep -- with many sand banks, marshes and temporary islands -- while to the north and west it is much deeper.)
Prochorus surfaces, floats around for a while resting, and then dives to the base of the rock to look around it.
(If I don't see anything, I head back home.)
While inspecting around the rock, Prochorus notices that it forms an overhang at one spot. Swimming there to get a better view, he sees that there is an entrance below, much like a cave. Further inspection reveals that the small cave is quite shallow as well as unoccupied. There are a few objects lying on the uneven floor of the cave, be he can't see them clearly as sunlight doesn't reach there. Another dive allows him to inspect them more closely, and they look suspisciously like bones.
Prochorus swims in and looks for a piece of bone small enough to carry in his beak. He takes it home with him. Do the bones seem old?
The bones he can take see in the dim light are on the large side. Too large for him to grab in his small beak and curved awkwardly. He cannot find small ones -- they probably get carried away by the tides which pull at him right this moment. The shallow cave isn't protected from the movement of the water.
I'll lifespont a level 5 spell to hear vis. Total -1 without aura.
(OOC: Hear vis, gotcha. But what were the rest of the parameters for the spell? Please be more detailed when you spont a spell, as it saves me from digging up whether the stated spell works. That woul be Base X +R +D +T. I had to dig up the parameter for Hearing before I was sure that the Duration was only Mom. Be nice to your SG! 
)
Prochorus feels a wave of exhaustion come down upon him when he casts his spell (2 levels lost). He is able, for a few moments, to hear the sussuration of raw vis somewhere nearby, but is unable to locate the source of this vis before his spell ends. And his poort scaup body is in bad need for fresh air anyway, so he quickly swims back to the surface.
(Sorry, I forgot duration was a thing in this game :O)
Prochorus floats around resting again. When he's feeling better, he casts formulaic Wizard's Sidestep on himself in case the owner of the bones comes back. Level 10, total 3 before aura. Once the potential fatigue from that wears off, he lifesponts a vis detection spell again, this time at base 1, touch +1 sun +2 = level 4. Total -1 without aura. He rests again, starting to feel bored.
When all that is done, Prochorus dives again and looks for the vis. He begins with the bones, swooping down and touching as many as he can.
His scaup form bobs up and down with the waves of the North Sea as Prochorus rests from his previous spellcasting. After a while, he casts his second vis-detection spell, this time without any difficulty (die roll of 1 followed by a 10).
Swimming down to the shallow cave again, he brushes against bones and stones in search of the vis emanations. After a little while, he touches one object that feels like raw vis. It is one of the curved bones, stuck in a crack in the rocks. Further search reveal that nothing else seem to contain vis.
Prochorus takes a good look around at and around the bone to remember which one it was. He then flies back home. Nothing much to do without a boat.
He can't see much in the darkness of the cave, but by touch he can discern that it is a curved bone about one wing in length, somehow jammed into a crack in the rock. He shouldn't have too much trouble finding it again.
He surfaces, preens his feathers, and flies back to Helgeland. After resting for a bit, he finds Dietlinde.
I hear the locals throw bread into the sea. Doesn't seem like a likely thing to do here, given the prices. Have you heard about that? Do you know who does it? I'd like to see if there's magic involved; could pay handsomely if we are lucky.
Dietlinde indicates that she will inquire about it in town. Might take a few days before she finds anything useful about it, though. Does Prochorus do anything else in the meantime?
While Dietlinde asks around, Prochorus flies around over the marsh to see if he can spot anything unusual there. Dwellings, people, monsters, anything.
Aside from the monastery at the northern edge of the marsh and a handful flat-bottomed boats being used near that same monastery, there doesn't seen to be much extraordinary about the marsh. Lots of ferns, small ponds, stunted trees, small streams. You notice a fox at one point, eating a waterbird.