According to Todd A. Farmerie, Ernicule de Boulogne is not an alias for Baudouin, but represents an alternate ancestry for Eustace. Todd gave the ancestry which I have for Baudouin. This differs from Turton, who has Baudouin as son of Gui Comte de Boulogne, Gui as son of Ernicule Comte de Boulogne (d. 972), and Ernicule as 2nd son of Guillaume I de Ponthieu, who is in my files. Todd Farmerie says that Ernicule is diminutive name for a young Arnoul/Arnulf, and probably refers to Arnulf II of Boulogne, or maybe Baudouin as the son of Arnulf II.