Rank Your Strut Benches by Morning Sun, Not by Gut

By mid-morning the roost hunt is over and a different game has started. The birds are on the ground, the hens are feeding, and a tom looking to be seen has a choice of openings: a log landing, a field corner, an old skid trail, a bench where the timber thins. On aerial imagery these candidates are nearly indistinguishable, and most hunters pick among them by feel or by whichever one they can reach quietly. There is a measurable difference between them. Openings do not warm at the same rate in April, and in Edgar County the sunniest benches bank more than double the first-two-hours sunlight of the shadiest ones.

Full-day April insolation ranks openings by total daily energy, which is the wrong question for a turkey hunter. A bench that is shaded until eleven and then blazes until dark can carry a strong daily total while being cold and wet exactly when the birds are choosing where to spend the morning. The hunt happens in a narrow window, so the measurement should live in the same window.

The two hours after sunrise are when hens come off the roost and begin feeding, when the ground is still giving up the night's cold, and when a strutting tom is deciding where to set up shop. The differences between openings are also at their largest then, because low sun angles interact hardest with terrain shading. By noon the sun is high enough that most openings are lit and the distinction collapses.

Two things separate a measured sun-hours surface from a shadow overlay. The first is accumulation: a shadow layer answers “is this spot in shade right now,” while sun-hours answers “how much sun does this spot collect across a defined window,” which is the quantity that actually relates to how fast ground dries and warms.

The second is horizon-awareness. The surface is computed against the terrain horizon on 24 compass bearings per cell, so it accounts for the ridge across the drainage, the timbered edge on the south side of a field, and the general skyline the opening sits inside. A south-facing bench tucked under a tall ridge can collect less morning sun than a flat opening in the middle of a field, and only a horizon-aware computation will tell you so. This is the same engine and the same terrain data behind our companion paper on roost benches, asked a different question: that paper asks when direct sun arrives at a bench, a timing question about fly-down, while this asks how much sun an opening accumulates through mid-morning, a warming question about strut zones.

Two openings that photograph the same on a map can differ by more than double in the sunlight they bank before the birds settle.

For Edgar County we walked the April 8 sun across the first two hours after sunrise (6:31 to 8:31 local, in five-minute steps) and at each step marked every bench sunlit or shaded by comparing the sun's height to the terrain horizon in its exact direction. Summing the sunlit minutes gives each bench a first-two-hours sun-hours value. Restricting to real slopes of four degrees or more, a median bench banks 1.83 hours, the range runs from under fifty minutes to the full window, and aspect explains most of the variation.

A parcel with a mix of openings will contain most of that range, which is what makes a ranking worth having: the difference between the best and the worst opening on the same ground is not marginal. One honest limit on the method as run: it uses the terrain-only horizon surface, so it captures the ridge across the draw and the general skyline but not fine-scale shading from an isolated stand of timber at an opening's edge. Where a lone tall tree line matters, the terrain figure is an optimistic ceiling.

The output is a gradient, not a pin. It ranks which openings on a piece of ground warm first in the morning; it does not say a bird will be standing in the top-ranked one. A tom's choice of strut zone is driven by where the hens are, by sight lines, by pressure, by what happened there yesterday, and by things no terrain layer records. Sun is one input among several, and on a warm still morning in late season it may be nearly irrelevant.

Where it earns its keep is triage. If you have a new parcel and six candidate openings and one morning to hunt it, a ranking gives you an order to check them in that is better than arbitrary. That is a modest claim and it is the true one. Two limits are worth naming: canopy changes through the spring, so an opening that is genuinely open in early April may be substantially shaded by the third week of May, and the surface models terrain shading rather than fine-scale vegetation, so a bench under a tall isolated stand can be colder than its terrain says.