Why is zijn used here and not liggen?
Because the birds are not lying down?
Should "waar staan de witte vogels" be accepted, or am I doing it wrong?
Also, what about "waar zitten..."
And waar zitten means where are they sitting
Waar staan woud be the verb to stand. Whereas waar zijn is the verb to be.
No the birds are not standing or lying or sitting. You just want to know where they are