seamew
The common gull (Larus canus).
The flocks are whiter down the vale, And milkier every milky sail On winding stream or distant sea; Where now the seamew pipes, or dives In yonder greening gleam, and fly The happy birds, that change their sky To build and brood
Now dance the lights on lawn and lea,
Where it comes from
From Middle English semewe, semawe (“seagull”), equivalent to sea + mew (“gull”).
Adapted from the Wiktionary entry seamew (CC BY-SA 4.0).