American Tree Sparrows -- Spizella arborea, winter well south of their breeding range. For them, eating like a bird means consuming around a third of their weight in food and a similar amount of water daily.
‘Who sees with equal eye, as God of all,
A hero perish or a sparrow fall,
Atoms or systems into ruin hurl’d,
And now a bubble burst, and now a world.’ ~ Alexander Pope, "Essay on Man", Epistle I.