Subtle Encroachment

I've noticed through observation that Mittens has a very sneaky way of getting other cats to vacate places she wants to be.  Where Puff or Romana will either complain to me or just go up and start swatting, Mittens simply goes over and claims just a little part (the edge of the Basket or a corner of a bed) then gradually stretches and moves over until she crowds the other cat out.  The other cat has a choice between accepting her company (and having her sprawl on top of him/her) or moving.  Even Finn is not immune.  She managed to crowd him off Di's bed last night.  With Fred, it depends on how determined he is.  The other night, she worked her way into the Basket with him, but he refused to budge.  Last night, she ended up pushing him off the bed as well.  Strangely, it rarely results in an actual fight.