🚀 go-pugleaf

I am not sure whether anyone of you have had such encounters but recently, I
discovered that birds would start to sing and chirp as early as three hours
before dawn! They are definitely not owls and would gather in flocks on the   
trees. It is usually still too dark for me to see them and the singing would
stop about an hour before dawn. I do not recognise the singing and therefore
can't identify them. 

Is it normal for birds (excluding nocturnal ones) to be active so early in the
day? Has it something to do with the geographical location (I am living in 
Melbourne, Australia)?
 

           Hong M. L.