Having various sizes of woody plants for them to build their own homes in can go a long way to attracting
native birds. Every year we find several nests in shrubs in our
yard. Most of our birds seem to prefer mid to low branches rather than high trees.
Keeping fresh
water available can be just as important. If you don't have some kind of water feature near your fruit trees it might be worth maintaining a bird bath near the trees would attract both birds during the day and bats at night. Damaged serving dishes can get a second life this way. Settling them near the ground makes them accessible to other critters like lizards and toads to give you even more helpers. Just be sure you have a plan for how to avoid mosquitoes.
I do have a couple of anecdotes concerning how effective bats actually are. One story is spending all night fishing on a fresh water pier under a light. Bats kept dipping and diving in the air around me but I never saw so much as one mosquito or moth. They were that effective at hunting. In comparison there was the year of record cricket numbers. There were so many that the bats never had to leave the caves. Without their regular hunting, walking outside each night you would be pelted with insects. The moths made it look like a blizzard and walking sounded like playing with bubble wrap.
Bats have very specific needs for both housing and location. Despite the tendency to simply nail a house up in a tree, most bats prefer a house located in full sun like the top of a cliff or a dead tree with no leaves. Pole mounting or against a high wall can simulate this. On top of that, you may need some patience. Even with a great house in a good spot it can take more than a year to attract a colony. You can probably tell I think a bat house is a great thing.