What's that about? New led street lights this autumn and springtime temperatures...
I even had a may bug in the porch last week.
Birds singing in the early hours has bugger-all to do with LED streetlights, but the milder temperatures may have something to do with it; I've heard three robins singing their little heads off at 3am recently, each from his own territory, and there are no LED streetlights of any significance locally, only one behind the flats out the back from me, all others around are sodium.
And I've heard birds, usually robins, singing at 4am, even when it's colder; it does seem to be urban lighting that's the issue, not the nature of the light, or temperature.
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Probs the wind woke them up, then they got hungry. They'll be back in bed before you..
It happens. Birds can't tell the time so if they wake up they will sing.
That'll be a "Blackbird singing in the dead of night..."
Somebody told me once that the birds aren't greeting each other - they are checking who made it through the night to see if they can snaffle some territory. Or something. Good story, anyway.
This would also explain why my cat is leaving for her morning patrol a lot earlier than she usually does in winter.
Weather may also influence them, I went outside last night around 1.30-ish, no birds singing, but it was very windy, compared to the other night when it was calm and quiet. Robins do seem to be the most vocal, but they're aggressive little buggers who'll defend their territory literally to the death, so I guess it's a 'come on if you're hard enough' set to music.