Scarlet Tanager is a vibrant songster of eastern hardwood forests, although it can be hard to get a look at the brilliant plumage of the male which sings from high treetops. Widespread breeders in the East, they are long-distance migrants that move all the way to South America for the winter.
Their spring return is in April and early May, when they surge northeastward and can be quite common in the extensive deciduous forests of the East. Their fall departure is in September and October, but is much less pronounced. This is a common pattern with these maps: spring migrants are colorful and vocal and readily detected by the throngs of birders. Although more birds are moving in fall (the adults plus all their young!), our eBird usage during September and October is actually vastly lower than it is for April and May. The STEM map accounts for this, but it does not yet account for the changes in detectability of the migrants themselves.
As a classic trans-Gulf migrant, seeing Scarlet Tanagers is a highlight of a visit to Gulf Coast migration hotspots like South Padre Island or Boy Scout Woods in Texas, Peveto Woods in Louisiana, or Dauphin Island in Alabama. Often they can be found feeding on ripening mulberries at sites like this, setting the tree ablaze with color along with other colorful fruit-lovers Baltimore Orioles, Summer Tanagers, and Rose-breasted Grosbeaks. Seeing this map cycle through brings back memories like this, since in April there is a brilliant and well-defined strip of color along the Gulf Coast (especially in Texas) which indicates this arrival of birds. Coastal areas are concentrating areas for birds for several reasons, but primarily because birds that find themselves over water while on migration head directly for land and concentrate there until it is safe again to migrate. We are pleased to see this effect showing up for many species (see Blackpoll Warbler on the Great Lakes and Northeast coast in fall) and we expect with time this phenomenon–and how it varies across species–will be better understood.