The Nature Conservancy has a great article about the efforts to protect and re-establish rattlesnakes in Massachusetts:

http://blog.nature.org/science/2016/04/25/recovery-saving-timber-rattlesnakes-wildlife-recovery-popularity-snakes/?src=e.nature.loc_b1&lu=1572839&autologin=true

The snakes are being bred in a zoo in Rhode Island. The plan is to create a timber-rattler sanctuary on Mt. Zion — an uninhabited 1,352-acre wilderness island in Quabbin Reservoir (Boston's water supply). The island is off limits to the public. It has a lush prey base and a large boulder field for hibernation. No other hibernaculum exists for miles.



There's an interesting page about Springfield Mountain here:

http://www.boudillion.com/oakhill/rattlesnakesong.htm

The writer says that the song is about the 1791 Timothy Mirick. Mirick came from Wilbraham, Massachusetts, once known as Springfield Mountain. Wilbraham is a suburb of Springfield.
Don't know if there are any rattlesnakes there now.

Roger McGuinn has a page on the "Springfield Mountain" song here:

http://www.ibiblio.org/jimmy/folkden-wp/?p=6974

Too rudy noo, too rudy nay
Too rudy noo, too rudy nay-i-ay

-Joe-