Black headed Gull thinks it's a Gannet! (1 Viewer)

Walking past the local river the other day I noticed a Black headed Gull dive bombing vertically at great speed from a considerable height-just like a Gannet.
It repeated this action at least three times.
It looked like it was trying to catch fish but was ,in fact, merely bathing and washing itself.
Maybe it was reared near a local Gannetry and learnt this behaviour from the Gannets.
A drinker in the beer garden of the adjacent pub looked as astounded as I was.!
Never seen a gull behaving like that before.

Guess it depends on what 'considerable' height means! I've often seen BHGs bathe like this with dives from a metre or so above water level. But if it was 10 metres, that'd be distinctly unusual.

Perhaps it was trying to dislodge parasites, or thought it was?

It was dive bombing from the same height as the old,two storey pub next to the river.
After dabbling around in the water it flew up to the same height,did a short hover,took aim and dived vertically again[repeated three times].
Very odd!

I've seen Gulls ( Herring, Lesser Black Backed and Black Headed ) dropping pebbles from a large height and then diving to try and catch them. Even diving underwater to get them after missing them on the drop!