Pike often are characterized as ambush predators, but that's usually not the case. They hunt with intent. A group of pike move onto a bar and make it a home area until the food gives out. They aren't schooled, although smaller fish often seem to be working the same general areas at the same time. Bigger pike certainly aren't pack fish, although several big pike may be working the same bar, again, until the food gives out.
Bigger pike locations tend to be deeper than smaller fish. So on shallow bars, most of the largest pike run the outside (drop-off) edge of weedgrowth, or are found in weed pockets along or immediately adjacent to the deep edge.
Generally, though, most of the largest pike in most bodies of water don't relate to shallow weedgrowth for long before moving to rocky areas at depths below the level of the first primary drop-off. Some of the best rocky spots usually are along points at the mouth of bays, or drop-off edges along rock humps in large deep bays or in the main portion of the lake or reservoir. In most clear and moderately clear lakes and reservoirs, key depths are 20 to 35 feet, although we have caught many pike as deep as 50 feet.
When ice pike become active, they roam an area, becoming familiar with it, just as coyotes become familiar with the series of fields and wood lots they call home. Pike recognize prime spots where baitfish tend to pass by. So they swim slowly along a weededge, then hold for a while in a particular weed pocket or at a particular weedpoint. They'll move up on a flat, too, to roust baitfish, looking for the weak or injured, or just looking for one of them to make a mistake. Or they might sashay through the edges of heavy weedgrowth and then station for a moment in a weed pocket or along an interior edge.
Few fishermen consider that the same thing transpires in deeper water, with pike keying their movements relative to rocks, using rocks almost as they do weeds, moving along the edges of rock slides, holding along rock points, and holding over sand and gravel patches (pockets) in rocky areas.
Probing shallower cover always has been easier because an angler in a shack usually can see the layout of the land below--the presence of edges and pockets. That's one reason so many anglers concentrate on shallow weedflats. Nothing wrong with that, particularly during the first part of the season. As fishing pressure builds, though, and as pike are caught and influenced by fishing pressure, and as they continue to naturally seek deeper water as the ice season progresses, fishing deeper becomes necessary.
Before the advent of underwater cameras, we probed deep spots by fishing them in conjunction with watching sonar. Maps usually suggest potential areas. Then it's a matter of setting out tip-ups and jigging to discover rockpiles, edges, and pockets, along with the presence of fish. An underwater camera like the Nature Vision Aqua-Vu takes a lot of the guesswork out of where to set baits--makes the process a lot more precise.
The best flats (or bars) usually have a variety of bottom and cover conditions, with weedgrowth an important part of any "shallow" equation, and rockpiles or clusters of rocks an important part of any "deep" equation. With regard to shallow patterns, the largest flats often attract the most pike, but they also usually require the most time to probe. When lots of people are working large bars, small bars often produce better action. You just have to be willing to move more.
Once pike move deep, on the other hand, they much more likely hold in precise areas; that is, their travel areas seem much reduced in size--perhaps no more than half an acre versus the acre or several acres they often travel in shallower water. In deep water, therefore, baits occasionally are moved in order to find pike that may not be roaming far; while in shallower water, baits are moved because pike also are moving and it may take several series of sets (with tip-ups) to discover whether pike are pushed up into pockets or running edges.
The rule also is to move sets more often during early season, leaving them set longer during midseason. Then, during late season, even though pike may be slightly more active, they never seem quite so willing to bite as during early season; so anglers continue to leave sets in place longer during late season.
If I'm not getting bites, I rarely leave baits longer than 45 minutes in a spot during early season. During late season, so long as I know I'm on a good spot, I often let my baits sit for the day. When I say let baits sit, I'm not suggesting leaving the same bait soak for the day. Deadbaits usually work best as the season progresses. And scent seems to be a factor in fishing for pike in cold water. So it makes sense to switch deadbait from time to time to maintain an attractive scent trail.