I'm in South Western Montana. Just curious for two reasons: I'm sort of an amateur wildlife photographer; I also hear that spring bear hunting can be productive in areas where cows are dropping their calves.
I would have to say they will start calving here toward the end of this month for the cows that came into estrus early this last fall...but they should keep calving well into the late part of May and Early June.
When placing a trail camera don't just look for a well used trail. What you want to do is look for a freshly used trail off by itself that goes from a north facing ridge, thick forest, brushy knob or some other similar bedding area to a food source. Don't forget water sources. Especially in the summer months the deer need water so look for a good trail going down too a creek surrounded by thick cover and place the camera 100 yards up from the water source.
Scent control is very important...