Migration Starting?

February 2023

I have started colour ringing Black-headed Gulls in my local parks.  On Saturday 11/02/2023 I recorded one at Bull Island.  What is unusual is that the Southside ones usually roost on Sandymount Strand. Daily travel is East-west. No record of going north south or south north before.  Movement usually starts late Feb.  Is this one on the move to its breeding ground already?

The movement distance is not significant.  I have ones from my Local Park from St Petersburg and Ukraine and everywhere in between.  The significance or oddness is the direction.  1,000's of Black-headed Gull ring reads and this is a first.