To specify further: technically the boy's not carrying a cow bell but a trychel (Treichel in German, Treichle in Swiss German). Wikipedia puts the difference thus: "As opposed to regular cast metal bells, trychlen are made of hammered sheet metal. This results in a less clean, clanking sound, but at the same time results in a bell that is less heavy and thus easier to carry".
What are little kids doing wearing masks and carrying cow bells on New Years Eve? Find out at TYWKIWDBI. Link
(Image credit: Hans Peter Klauser)