Great! I too, am a "birder". If you have a water source near you, you will get purple martins if you put up the houses. It may take a few years, but you will get them. A martin consumes 3X as many insects as a bat per unit weight, so they are very helpful.
Indigo buntings are beautiful. In southern Mo, we are lousy with indigo buntings and the whole spate of warblers. There are actually scarlet tanagers, summer tanagers, and pileated woodpeckers here as well. The whole area used to be swampy (there are cypress swamps nearby) that tends to attract such birds. We have about a dozen feeders in our backyard to attract different birds and are also graced by an albino deer.
I would suggest getting the ap on your phone which identifies birds by thier calls. It is called "song sleuth". It is somewhat hit and miss, but it at least gets you in the right ballpark.
Too bad on the apple treatment. Again, call your county agent and have them come out and take a look; that is what they are paid for and you would like the information.
Yes- I have all the "geezer" hobbies. One of my big ones is rebuilding old "woodie" cars. I have several (I sold all the rest of my car collection) and have given a few to my kids. I just bought a 41 international K3 woodie, which was parked in a barn for 50 years. I will get to restoring it in a few weeks. I love doing the woodwork and making replacement parts. The dilemma is that most of these were grossly underpowered and have non-synchromesh shifting which requires "double clutching"; one must either suck it up and drive 45 mph or install a modern engine, tranny, rear end, suspension, and disc brakes. I have a ww2 halftrack that requires "double clutching" and it is a pain in the ass to drive. The purists hate "resto-mods", but I am not a purist. This one will take me about four years, as I cannot devote the time to it that I would if I was retired. Nonetheless, such a hobby is nice, in that it consumes tons of time in planning and then implementing the process- you learn something new with every car. I also have a collection of ww1 and ww2 weapons, military medals, and watches. All those things keep you occupied when the kids are gone.