Kyoko Mori answers in One Bird (1995):
I raise my left arm and begin to wave as the birds disappear over the neighbor’s houses, and my eyes ache from staring into the sky. I know they will be back among the flocks of sparrows in Dr. Mizutani’s yard–eating the seeds from the feeders, splashing noisily in the birdbath. Only I will never again be able to tell them apart from all the other young sparrows, the hundreds of this spring’s babies with their streaky breasts and pinkish legs. So even after I can no longer see my sparrows, I keep waving in the direction of their flight. If they could look back, they would see the blurred motion of my arm–a rough, repeated outline in the air, the closest thing I can manage to a wing.