When a buck "blows," it means that it is forcibly expelling air through its nostrils, creating a loud, snorting sound. This behavior is typically a response to detecting danger at a distance or something that is out of the ordinary. The sound is meant to alert other deer in the area. It can be a sign that the deer has detected a potential threat, such as the presence of a predator or a human. This behavior is not limited to bucks, as does can also exhibit this behavior. It is often associated with a sense of alarm or distress and is a way for the deer to communicate with others in the area. The blowing sound is a natural defense mechanism that helps deer to stay safe in their environment