escuchar + noun

Hola David L.

You're absolutely right to wonder about "al canto de los pájaros" — the more natural and grammatically correct phrase is actually "escuchar el canto de los pájaros." The verb escuchar is transitive, so it takes a direct object without the need for the preposition a when the object is a thing (like el canto). Using al canto (a + el canto) would imply direction or an indirect object, which doesn't apply here.

So while escuchar el canto de los pájaros means “to listen to the birdsong”, the sentence escuchar a los pájaros cantar means “to listen to the birds sing” and puts the focus on the birds doing the action.

Both are grammatically correct, but they express slightly different things. The first focuses on the sound, and the second focuses on the action of the birds. The correction you received likely aimed for the structure that best matches the English prompt “listen to the birds sing”, which naturally calls for escuchar a los pájaros cantar.

Hope that clears it up!

Saludos

Silvia