They will hit very aggressively right up to spawn and then again a couple weeks after.
They don't all spawn at the same time so that doesn't mean some can't be caught.
It may be a larger percentage of males during the spawn.
Bluegills spawning on beds is pretty cool. It's also cool to let a few of the big spawners go.
Each person has to decide what that size may be. Latest info is the lakes need the biggest gills.