The Sayaca Tanager is the southern and eastern replacement of the Blue-grey Tanager T. episcopus to which it is very similar. See the distribution map at xeno-canto. In the few areas where the two might occur together, the Sayaca is told by its blue shoulder while the Blue-grey has a white shoulder. There are many variations of colour on the shoulder. For example, the subspecies of Blue-grey Tanager that I knew in Pereira, Colombia, had a blue shoulder patch.

In south-east Brazil note the similarity with the Azure-shouldered Tanager T cyanoptera. This has a larger bill, a deep blue shoulder (sometimes difficult to see) and a greenish tinge on the flanks.