Welcome back Brown Thrasher. Typically the Brown Thrasher is the second breeding season resident to show up in my yard. It normally follows the Towhee every year so when I see my Towhee, I knowhee that the Thrasher isn't far behind. Thrashers are one of our migrant Mimics, along with the Mockingbird (year round resident) and the Gray Catbird who is also a migrant. Of the three, the Thrasher has the purest voice.
The three mimics can be identified by voice most of the time. Here is a breakdown of their song traits.
Northern Mockingbird - Sings frequently and usually repeats the same song 3 or 4 times. If you watch the Masters and listen, you can hear the Mockingbirds in the background especially around "Amen Corner."
Gray Catbird - The Catbird has the least accurate imitations of the other bird songs. It can be told apart from the other two because it mixes in the "mew" sound of a cat.
Brown Thrasher - The Thrasher has the most accurate renditions of the three.
If you hear the songs and are trying to figure out which of the three it is then try this. This method will help you correctly identify a singing hidden mimic over 95% of the time.
Does it repeat each song about 3 times? If not you can almost always eliminate the Mocker.
Does it mix in the "mew" sound? If not you most likely are hearing a Brown Thrasher.
The one stumbling block with these steps is that you could hear the 'mew" sound and if you are unfamiliar with the voice quality, assume that the singer is a Catbird but it is really a Thrasher mixing in the songs of a Catbird. It has happened to me a number of times.