Birds have various ways of blinking depending on the species and the circumstances. Like us, they have upper and lower eyelids, though the upper lid only moves down in parrots, owls, pigeons, and a few others. The lower lid rises with drowsiness and when the bird is preening. Birds blink when they turn their heads using a ‘third eyelid’, the nictitating membrane that moves horizontally from the inner part to the outer part of the eye.
Source: Animals 2023, November 26, 2023. Link.
Blinking evolved as a way of keeping the cornea moist when fish first left the sea and is an neglected marker of vertebrate evolution.