Movements in North Sutherland – also over the sea?

Canisp moved north from Reay Estate on 4th October and at 1pm was south of Loch Eriboll flying west at 34kph.  At 3pm there was a 2D GPS fix out over the Atlantic Ocean 41 miles north of Strathy Point and 20 miles west of mainland Orkney. This is a remarkable movement but it would have been more certain with a normal 3D fix. Two hours later she was back south of Tongue and then moved to the Ben Loyal/Strathnaver area