Unless you desire to get up at 4:30 in the morning, you're going to have to invest in some curtains either way. At that point, the exact time of sunrise doesn't really matter.
Using wall clock time as the measure, this would mean the birds sleep later. The hour we used to call 4am would be called 5am. Birds will wake up at the same physical time, but what matters is what our clocks say.
[0] https://www.rspb.org.uk/birds-and-wildlife/advice/how-you-ca...