The convor was first introduced in The Clone Wars season three episode “Padawan Lost” when Ahsoka Tano is captured by Trandoshan hunters.
They could just be a visual nod to excite fans of Rebels and The Clone Wars.
Whether or not that’s the case with the convorees in Episode VIII remains to be seen, but the possibilities are too tantalizing to avoid speculation altogether.
Has he already spent his time on Ahch-To talking to mysterious birds?