@Deb2022,
Hi! I am a bit envious that you have so much fresh fruit each season...
I don't know much about fruit trees (though we have guava, papaya, and banana trees growing in our yard) but I don't think you increase the number of fruits by pruning the tree into a dwarf height or a big bushy thing. So I believe the number of pears you harvest is the same -- whatever is within arm's reach, or by ladder. I could be wrong.
Next, will you be depriving the birds of a food source that has been there for the past several decades? That's generations of local birds depending on a reliable natural source of food. Are they somehow being a pest?
And -- the size of the tree supports the health and growth of a reasonably extensive trunk and root system. The tree sap required to keep the whole system healthy is equal to the task, but if you reduce the foliage and supply of tree sap that supports the trunk's and root's health, will a fruit tree begin to slowly die off?
"Balancing nature" is always tricky... My personal feeling is to let the birds have whatever they will eat, and harvest what is within reach. If you prune the tree, you can still only reach so high anyway. I can't eat 100 pounds of pears, though my wife could can some and share a lot. But we wouldn't begrudge the birdlife some food, either.
If you are set to prune it anyway, maybe best to visit a local orchard and ask the owner about pruning a fruit tree -- how, how much, when, and the outcome. Of course, the birds will find another source of food elswhere, and some will die, too.