I'm not using fly. I'm not entering Lumiose city...I'm biking around trying to reach him, and each time I enter a new zone, he enters a new zone. It is literally impossible to be in the same area with him, despite doing everything that google search is telling me to do.
I don't don't if the runners work the way they used to, but you can find an area where the map change triggers and just cross the map over and over until its in your area, use a repel, and force the encounter.
Don't chase it, let it come to you.
"Which is worse - The sleep which never ends or that which never comes?"
If I sit in one spot, he sits in one spot. If I move forward one zone, he moves forward. If I fly, he moves somewhere randomly. If I leave a zone and come back to it right a way, he stays in the same spot. There is nothing I'm able to do to get close to this stupid bird.
Find a route that connects to another route. Cross between them several times, check each time to see if the bird has entered your route. It will eventually, it might take several tries though. Make sure the routes have grass nearby, and any HMs necessary.
Inside there was a bread roll! ...But it bread rolled away