Can anyone enlighten me on the migratory patterns/behavior of robins?

Honestly, I never thought much about it. All robins looked the same to me. How was I to know that they come and go? Until this partially albino robin started showing up in my yard about 6 years ago. She comes around about the same time every year, the first week in April and stays for about six weeks. Hangs out in a territory of about 4 suburban front yards, maybe a little more than an acre plus, though if she’s hanging out in the back yards too, I don’t know because I can’t see that so I can’t say for sure how big an area she “hangs out” in. Six years now she’s been coming back. Where might she go when she leaves here or where might she have been before she comes here? How long would she stay in one place?