Is a mockingbird brown thrasher?

No, a mockingbird is not a brown thrasher. While both mockingbirds and brown thrashers are songbirds that frequent North America, they are separate species and belong to different families of birds. Mockingbirds are members of the family Mimidae, known as mockingbirds and thrashers, while brown thrashers belong to the family Passerellidae, referred to as New World sparrows or American sparrows.