Just learned that Richard Sivertsen died from a FB post by Jennifer Beth. As privacy settings don't show it when I just link it, here is the text:
Sharing the very sad news of my uncle Richard Sivertsen's sudden passing. Much of my appreciation for acoustic music and wildlife is because of him. We will be having a memorial gathering at Vasa Park in NJ on Sunday 8/6/17 at 2pm. All friends are welcome to join us to share memories, pictures and stories of his life. Anyone who wishes to may donate to Longwood Gardens in his name.
This is sad news for all who knew him. R.I.P. Rich.