The ones visiting our feeders last year left first week of October. (Just personal observation, I made a note of it in my garden journal.)

The lady at Wild Birds Unlimited in Chattanooga told us that, typically, they start leaving around the 1st or 2nd week in October and arrive the 2nd or 3rd week in April. She also told us leave the feeders out from "crazy day to crazy day" (being April Fool's Day and Halloween). That would ensure plenty of time for stragglers to feed. I can usually tell mine have left by the 10th or thereabouts of October (and I sure do miss them!).

I'm in Seattle working since Sept 12.
My oldest daughter has told me that she is seeing them a lot less often now and the feeders are not being emptied.
She is changing the nectar every 3 days, before I left town they were being emptied by the birds every two.

I havent had any for about 10 days now. Hate to see them go. Really had a lot this year.

Gone from StMtn also........