Korczak always knocked on the door to his empty room at the attic before entering the room just not to getting sparrows afraid by his sudden appearance! Korczak was also feeding the sparrows which flocked to receive their groats on a specially constructed for this aim board (o)at his window at the attic. He also rebuild a window so sparrows could warm themselves there during cold days.
Igor Newerly, Korczaks secretary for many years, told us that Korczak loved to watch the sparrows and wrote two note books about them.
