Garage gulls

The Safari doesn't know the collective noun for gulls but a squabble of gulls could be good.

No proper safari-ing in the mizzle today, to be honest we were too lazy to go out, so we stuck some left overs on the garage roof and waited in the back bedroom for the rucous to begin - it didn't take long.
First down were a few Black Headed Gulls.

Mostly adults but this first winter bird was bold enough to tackle the turkey carcass on it's own.

It wasn't long before the bigger boys came down to investigate. A nice first winter Herring Gull strode purposefully towards the goodies.

This third winter Herring Gull also has its eye on what's on offer.
Then we spotted this interesting Herring Gull, but what exactly is it?
Plenty of white on the primaries, looks dark on the mantle, possible adult argentatus?

But looking at this pic the mantle looks paler than the 3rd win HG in front and the adult BHG behind, so the 'real' tone could be anything really.

The underside of P10 looks to be all white a long way up. Not sure if its an argenteus from north-west of their range or a bona-fide Scandinavian argentatus; we don't think it was dark enough or large enough, any pointers anyone. Couldn't get the wanted open winged shot unfortunately.

Below is a more typical adult argenteus for comparison, with the 1st winter behind in the first pic.

Where to next? A proper safari tomorrow, there's three year ticks within range and only a couple of days to knock em off.

In the meantime let us know what's giving you ID dilemas in your outback.