Bonis Avibus Under favorable signs. This isn't the standard post for the religious phrases section. It's about Roman religion rather than Christianity. Literally, the phrase translates as "under good birds". The Romans relied heavily on augury, the practice of interpreting the flight, entrails and other bird behavior to look for omens. Funnily enough, this practice isn't as esoteric as it may seem, as many cultures still use birds for omens or signs (consider the allusion of ravens or crows to death). Several other cultures have their own superstitions and auguries (in the Philippines we have one about how if a hen keeps scratching behind your bedroom, somebody in your house in pregnant. It has happened to me although me without being pregnant but only people gossiping that I was because of course chickens never lie). And there are also many incidents in Roman and later literature where augury occurs besides the one starring the drowning chickens (if you know what I mean).