I'm curious, what's your source? Other than that, I'm suprised that the Saabs would be heading to more-temperate climates, as these seem to be good winter-weather birds and have served the north-central states well over the years.

Perhaps a well-deserved, "retirement" to warmer weather? Nevertheless, not sure what DL+NW will or can replace them with at the smaller airfields they usually serve. Let's hope that this doesn't spell the end of Airlink/Connection scheduled service to small stations like ABR, etc.