Aw, love those sparrows, too...so quick and flighty and like you, robins appear here in the spring, have their little ones then who knows where? We seldom see them here in mid-summer. At least I don't and we spend a lot of time in the great outdoors. In summer. Not winter. Hate it already and it's not even here. And I have to order a new winter jacket. Blah.
HOWEVER!!!....
https://www.youtube.com/watch?v=s3Biuo0MwEE