emperor goose
... that the head of the emperor goose frequently turns from white to reddish-brown in summer, due to its feeding in tidal pools with iron oxide?
... that the head of the <b id="mwA2U"><a href="./Emperor_goose" id="mwA2Y" rel="mw:WikiLink" title="Emperor goose">emperor goose</a></b> <i id="mwA2c">(pictured)</i> frequently turns from white to reddish-brown in summer, due to its feeding in tidal pools with <a href="./Iron_oxide" id="mwA2g" rel="mw:WikiLink" title="Iron oxide">iron oxide</a>?