The moorcock is a game bird, the male black grouse, characterized in heraldry by its two projecting tail feathers. It’s a period charge, found in the canting arms of Myddylmore c.1460 [RH], and more famously in the arms of Sir Thomas More, 1478 [Wagner 68]. The moorcock is close by default.
Vostroi Ivanov Kievich bears: Or, a pale bretessed between two moorcocks close respectant gules each gorged of a coronet argent.
Lovell Hastings bears: Argent, a fess wreathed vert between three moorcocks in fess and a patriarchal cross gules.