Fruit Tree CSI Needed

I am mystified by two problems with my native fruit orchard, in my back yard in Minnetonka.

1. The currants are going missing, long before they ripen. They are tiny, hard and green. The plants are young and I didn't notice fruit last year, the first summer I had them.

2. Leaves on the top of a mulberry tree are disappearing, but the fruit remains. If it were deer, I would expect them to take the lower branches first. I don't see any worms. The tree is surrounded by a 4' high hardware wire cage so I don't think the woodchucks are climbing up to eat the leaves. They seem too clumsy to manage that. We also have opossums in the yard, who might be more agile.

Does anyone know of any reference books or websites to native plant pests?

Should natives be pruned? One of my Serviceberry bushes shot up tall, but has very few berries. The short bushes have good crops. My currents sprawled out almost flat when I took away their hardware wire cages because they outgrew them.

Thank you for your help.
Peggy Kvam