A couple of questions about house sparrows and multiple broods?

Question

Can anyone tell me how soon after a house sparrow brood has fledged would the parents start on the next brood? The chicks raised by the pair in my nest box fledged on Friday, and as soon as Monday the adults (or so it seemed-more on that further on) were already showing much interest in the box again - they have both been sitting on top/going in and out sporadically since - are they geting ready for another brood already? The fact that neither of them have any great distinguishing features to know if it's the original pair or not brings me to my next question - if it isn't the original pair, would they be permissive of a different pair using thier "home" in this way?

KatTai · Accepted Answer

One pair in my aunts colony are currently on their third brood! They seem to start pretty quick after the chicks have gone, plus I think they get fed by other adults not just the parents as I sat and watched fledglings being fed by two or three males, which may mean the female can start sitting on the next clutch much quicker as the females aren't seen that much, definate housewife sparrows! Saying that, there are more males than nests (9 nest sites, but one has been abandoned now the chicks have gone as the male got his head stuck as he tried to get in through the hole and had to be rescued) so perhaps a lot of the males haven't been able to pair off. 
 With most birds, the idea is to start on the next brood asap so they will start on the next lot as quickly as is possible.