For most of the fall they'll be on the flats around the mangroves and oyster bars on the high tides, and in the potholes on the low tides.
(they; 'll be; on the flats around the mangroves and oyster bars on the high tides; T:For most of the fall)
they
'll be
on the flats around the mangroves and oyster bars on the high tides T:For most of the fall