Southern Black-backed Gulls

It’s lively out there on the shoreline as the Southern Black-backed gulls breed from September through to March but mainly now, in November.  They’re a robust species, dominating the shoreline and top of the pecking order when it comes to muscling in on opportunistic feeding.  I was intrigued to see two adults tussling in a ‘beak pulling’ contest.  I wondered if it was a play for dominance or perhaps a mating ritual.  Anyone have any knowledge on gull behaviour?

Two Southern Black-backed gulls square up for a game of beak pulling.
Two Southern Black-backed gulls square up for a game of beak pulling.
And the battle is on, engaged and hooked.
And the battle is on, engaged and hooked.
Here in the line-up are the juveniles in their mottled plumage while the mature adults are black and white. Their legs and feet are a bluish-yellow, which is a useful identifying feature from the Lesser Black-backs which have bright yellow.