Eric, there are two studies in which birds were noted as substantial parts of a ball python's diet - mainly male. One study was based on the gastric contents (I've provided it before to people), the other was a study regarding denning behavior in which the behavior was noted as prevalent. I'd have to refresh my memory as to whether it was associated with breeding behavior - in which males forego denning and ambushing while actively seeking out mates- or some other behavior.