Hi,
This sounds like something a predator would do – but probably not a natural predator. Feral cats or even an African Wild Cat/domestic cat hybrid might do something like this. Rats will also do this. It’s highly unlikely to be another bird. A bird of prey would consume the kill, not just remove the head. If this was another species, a territorial dispute between pairs of the same species could be the cause. But I don’t know of any dove species that would be that aggressive, or have the ability to remove the head. And parasitic species aren’t going to choose doves to raise their young, because doves have a unique feeding style that wouldn’t work on other species. Also this isn’t how brood parasites dispense of the host’s chicks. This is more likely an animal that kills out of partial instinct, but not so much for food, and a feral cat is the most likely suspect.
Thank you for asking Lafeber,
Brenda