No interactions present.
This is certainly a Yellow-legged Gull, which would be the most common 'large white-headed gull'(or LWHG!) in the region. As well as the darker back and yellow legs mentioned by Syrphus, there are also some slight structural differences, and differences in the wing tip pattern.
The taxonomy of LWHG's has been in a state of flux recently, and still is!
It is possible to find references to Yellow-legged Gulls under the names Larus argentatus michahellis, L. cahinnans michahellis, and L. michahellis.
Originally they were treated as a subspecies of Herring Gull, they were then treated as separate from Herring Gull - but 'lumped' with Caspian Gull (usually under the name "Yellow-legged Gull, Larus cachinnans"), and now Herring, Yellow-legged and Caspian are all treated as separate species.
There's nothing like a good bit of confusion!
One thing's for certain...it ain't no mammal!
Otherwise...I agree with Roy.
My Flickr photos...
Lat/Lng: 44.1363, 9.685