@hightor,
The big one near the house was an oak.
The ones that were dying were pines and some were quite tall and we would watch them sway in the air whenever there was a high wind.
Sadly one of our holly trees had to go - it wasn't too big but they couldn't get to this incredibly big tree that was very obviously dead with out getting that out.
Our land is on a couple acres about half or more is wetlands and wooded. The tree guys assured us they could remove any trees from wetlands that were a danger to us - these were more the one on the edges of the wetlands and our yard.
I think the squirrels are particularly angry with us.