ну и если копать, то в оригинале там "peacock".
a это мог быть и фазан:
The yew hedges muffled the sound of the men’s footsteps. There was a rustle somewhere to their right: Yaxley drew his wand again, pointing it over his companion’s head, but the source of the noise proved to be nothing more than a pure-white peacock, strutting majestically along the top of the hedge.
“He always did himself well, Lucius. Peacocks...”
Yaxley thrust his wand back under his cloak with a snort.
update
ниже в комментах выяснилось, что насчёт фазанов я прокололся :-(