 More material evidence exists for the ecology of "B. advenus" than for any other member of the Hesperornithes, with the possible exception of "Hesperornis regalis", but still much is left to conjecture.The loon-sized bird was of middle size among its relatives and had a markedly elongated neck.Presumably, it thus behaved in a manner similar to today's darters, hunting smaller, more mobile prey than its larger relatives.