One way to survey the ant activity is to place a dab of peanut butter on index cards and place six or more cards in every room of the house in areas suspected of greatest activity. Place the cards along known ant trails, on windowsills, near electrical outlets and cracks, by doors, etc. The cards should be left undisturbed for several hours and then the number of ants on each card should be noted. Then place ant bait stations in the locations having the greatest ant activity. You should use from four to six bait stations in each room.
Baits exploit the natural foraging behavior of ants to find and share food.
The bait is spread throughout the colony by this behavior. On the negative side, baits tend to be slower acting than sprays or dusts requiring patience by a homeowner. Also the shelf life of bait is limited by the susceptibility of the food component of the bait to spoilage. Once the bait begins to spoil, the ants will reject it. There are numerous baits available.