where have all the sparrows gone??

One of my fondest early childhood memories is associated with sparrows- the little birds which were so commonplace not very long ago. They used to set-up their nests somewhere up the walls, in the windows or bushes or some other equally conspicuous part of the house- always accessible! So we’d pile-up the chairs or other pieces of furniture, one above the other and reach up to peep into the little birdie’s nest. And then, what we saw was some strange looking creatures- baby birdies- extremely delicate! So, we’d pick up one or two of them, touch them lovingly, gaze at them in wonder, and then put them back in their cozy little home. But to our surprise, we’d later find them lying on the floor, dead! How did they fall? We’d wonder...and then we were told by elders that sparrows are touch-sensitive, i.e. if you touch a sparrow and leave it free, it gets excommunicated by the sparrow society- they never accept it back into their fold as one of their own.
Humans don’t kill sparrows. Still, one hardly spots them flitting about in the front or backyard of the house these days. There seems to have been a steep decline in their number over the last one decade or so. Are they on the verge of extinction?