Seed heads

Can anyone tell me why when seedheads are ready for collecting, I should store and save the seeds rather than sow them now?
Anything sown in the spring will be eaten by bunnies but as there are fewer bunnies around now I'm thinking a September sowing will have a better chance.

 

Wouldn't birds or squirrels eat them if sown now?

Also if sown now, maybe they might germinate then die.

 

Depends what you are collecting. Some annuals , such as cornflowers, calenduals and larkspur can be sown now and overwinter. But they would still be small come spring when the bunnies would e3at them.

 

Surely a self-perpetuating annual would set seed now and flower again next year?