Most of you seem to be describing a few garden birds cheaping away outside the window.
The real dawn chorus only really happens at stupid o'clock in the spring when all the resident birds are well into setting up their breeding territories, and the migrants are just beginning to arrive and singing their heads off to do the same. It can be deafening; it's certainly quite hard to pick out individual voices.
That winds down as singing males snag themselves mates (in many migrants, the females arrive in a later wave and take their pick from among the furiously singing males) and transfer their attention to alternately raping them, making sure no-one else does, and trying to have it away with all their neighbours' mates.
There's sometimes a little peak of singing activity in some species while eggs are incubated and males have less to do. Then when chicks hatch, it's all hands to the pump to feed them for a couple of weeks until they fledge, and then the whole thing begins all over again. Particularly in migrants, this cycle is well synchronised, so you do find that these species' song stops altogether for two or three weeks, and then they all spark up again within a day or two of each other.
By the time we get to July and August, the breeders are worn out - literally. They're typically very thin - they've put all their energy into raising chicks and singing, and not enough into maintaining themselves. Plus as soon as breeding's finished, they start moulting. While moulting, their flight is compromised, because some feathers are missing. Singing takes up a lot of energy that could be spent growing feathers, and it's best not to draw a predator's attention to yourself by singing when your ability to get away is reduced. And there's no point in singing anyway, since the females are also moulting and not interested in mating. So during the moult, birds go very quiet and hide away in the bottoms of bushes quite a lot.
Not only do they re-grow most of their feathers (in small groups in passerines, so that they can always still fly), their reproductive organs shrivel to almost nothing, saving weight. In that state, they produce almost no hormones, so their sex drive declines - until day length triggers those organs to swell (to surprising proportions in some species - you wouldn't believe how sex-mad dunnocks are).
Robins sing almost all the year round. They're one of the few species in which females sing, and both sexes hold territories in the winter. There's a sort of uneasy truce between males and females during the breeding season.
Flocking birds like sparrows and starlings do a lot of sort-of singing and calling all the time, but since they are colonial breeders, it's more about chatting with the neighbours and organising foraging parties than "oi, are you looking at my bird!?"
