Robins and the Great Backyard Bird Count

In recent years, it has dawned on me that the first American Robins (Turdus migratorius) of the year appear in my backyard sometime during President's Day weekend, coincident with the Great Backyard Bird Count. Is that merely because I spend more time in the backyard on the alert for whatever birds might be about, or does it reflect an actual influx of robins into the neighborhood. This graph from ebird (which shows the frequency with which American Robins are reported in West Virginia) indicates a major influx of birds into the State between mid-February and the first of March. This trend leads me conclude that these are not birds that have lingered undetected in the neighborhood all winter, but are in fact early-arriving migrants that have wintered further south.