Maith thú, a Sheáin! That's all correct.
Here are a couple of other forms you might like to know:
Cloistear na héin gach maidin = The birds are heard every morning (the impersonal form of the verb/briathar saor; also Ní chloistear, a chloistear, nach gcloistear, etc.)
Fan go gcloise tú na héin = Wait till you hear the birds (present subjunctive)
Seo an fear a chloiseas na héin gach maidin (relative form which can be used instead of the simple present tense form)