Autumn is a peak time for migration. Increasingly, birdwatchers are aware of ‘visible migration’, AKA vis mig, when birds can be seen (and/ or heard) in the actual act of migration. Migration ceases to be a theoretical concept and appears as an observable reality. Most vis mig watches consist of observing birds flying over a prominent spot. But you can also observe birds on the move at places like mud-fringed gravel pits and the like. Birds such as waders may be on the move, often in small parties, at different times of day, and seek out such sites for a bit of a wash and brush up, a drink and perhaps a brief refuelling feed. If you check such a site first thing in the morning, you may leave having recorded no waders. Come back a bit later though, and there could be a few waders dropping in before heading off. Come again even later and there could be a whole new set of passing birds popping in and out. Only by repeated visits (or a long, continuous vigil) will you be able to gauge what is really appearing at your favourite local site.