What would decapitate a house sparrow?

Decapitating a house sparrow could occur due to various factors, such as predation by larger Birds of Prey, collisions with Windows or vehicles, or injury from machinery like lawnmowers or other equipment. Additionally, intentional harm from humans or accidents involving sharp objects could also result in decapitation. It's important to note that such events are generally unfortunate and can highlight the vulnerabilities of small birds in urban environments.