We rely on the eye test. It requires good optics and patience. Our general rule of thumb is, a moose is 10" across the eyes. After that its math and good judgement. Optics are key!
Ears are tricky. Moose radar. They can be straight up. Flat out. Moose can rotate each ear independently. Ears move a lot. They hear very well. See not so good. Ears, I do not trust to determine antler width.
40.5 Idaho. If you're curious this one scores 138 5/8. For reference. I like knowing what an approximate score when I'm scouting. Not that I care if I books or not. But anything close to that mark is a nice one in my mind. And on a OIL tag I like knowing what "nice" is.
FYI, I didn't get the spreads in on my post. My bull is 43" and my sons is 52"+ both were taken in northern BC. Caution moose hunting is addicting. I'm weighing a third moose hunt!
Very uncommon in my area..a spike fork.
He was eating rose hips in my back yard.
The unit I hunt (interior AK) legal bulls are spike-fork, 3 brow tines or greater than 50 inches.
Here are a few I've taken over the years. it should give you a good gauge on size differences from bulls in the 30" range to bulls up into the 50s and 60s.
Starting with the top bull at 64", second at 57", third at 42" and fourth at 30"