I was interested in reading a recent paper called "the dispersal and migration of northern gannet morus bassanus from Channel Islands breeding colonies" by P.K Veron and M.P Lawlor in AW Seabird number 22.
They looked at where ringed birds from the Channel Islands go in winter.
The older birds very rarely venture into the Mediterranean. More even disperse northward than make it into the Mediterranean. I wonder if this is a function of where their preferred food is though I am a self-confessed novice when it comes to the habits of Atlantic birds?
What I found interesting was that younger birds seem more likely to fly into the Mediterranean up to (but not much further than western Libya). This could be a statistical fluke because there are less records of young birds but it does appear that they see going into the Mediterranean as a mistake that many of them don't repeat when they get older.