My biggest concern is that investing in my nesting grounds might not be the best place to start for the obvious reason...super high prices and honestly I remember after the 1994 earthquake how this market tanked.

As for the other half of your nest egg, keep a bit out in cash so you have it to deploy quickly if you find something awesome, but take the majority and toss it in a low-fee index ETF to get some low-risk returns - you can pull out what you want, when you want it (unlike a mutual fund), instead of having to refi or sell RE to free up capital.

At this point, I'm thinking I'd like to invest in multiple properties - some for appreciation as a retirement nest egg and some for cash flow for now. 

Time to leave the nest already!

They mate and nest in April? 

If your goal is to maximize long term wealth, holding two houses in San Francisco is probably the better retirement nest egg in 30 years, when compared to buying cash flow rentals in Tennessee.  

Of course you could have mitigated most of this by a simple 48 hour notice to enter after first letter and verified what was going on in the house by 'inspecting' the house.But the majority of posters are correct, ignore her until she starts coming around, she might be a bored housewife too, just looking for a bees nest to poke at.

They build big nasty baby bird-poop and mite-filled nests. 

We did pay for one professional treatment for the wasp nests and told them everything else is in their contract and it is their obligation.

This happens because lint, bird's nests, and other debris can collect in the dryer vent.