For comparison, I had one bird, same species, a White-throated Sparrow, spend the winter in my front yard. This was a little unusual but 3 other people on the MOU listserve also reported that they found other individuals in various locations around the Twin Cities this winter. Another difference, "my" sparrow had tan stripes on his head instead of white. See Dan Tallman's blog for more about this.
After Carpenter, I went to Afton State Park and checked bluebird boxes. I have several assigned to me but only one had a nest last week. This week, it has eggs !
The parents were near and not happy so I quickly left. I hope we have good luck !