Why are there so many crows in Tang poetry?

Clear sand. melancholy autumn thoughts

Dead vines, old trees, faint crows,

Small bridges and flowing water,

The ancient road, the west wind and the thin horse,

The sun went down,

Heartbroken people are at the end of the world.

In China culture, crows are ominous animals.

We often see it on TV, before the danger comes, or before.

There were crows when Xing was executed.

The crow in the poem mainly reflects the author's sad mood.

In fact, the most common words in Tang poetry are: poetry, wine, flowers, moon and sorrow.