Pan-American migrants

Species from South America have been migrating toward the Adirondacks for a very long time: 2.7 million years, to be as exact as a biogeographer can.

Not quite 3 million years ago is when South America, which had been drifting around the South Atlantic and South Pacific disconnected from other major land masses for tens of millions of years, collided with its immediate neighbor to the north. The result was Central America, including the isthmus