[Of the goose] The goose marks the watches of the night by its constant cry. No other creature picks up the scent of man as it does. It was because of its noise, that the Gauls were detected when they ascended the Capitol. Rabanus says in this context: ‘The goose can signify men who are prudent and look out for their own safety.’ There are two kinds of geese, domestic and wild. Wild geese fly high, in a an orderly fashion, signifying those who, far away from earthly things, preserve a rule of virtuous conduct. Domestic geese live together in villages, they cackle together all the time and rend each other with their beaks; they signify those who, although they like conventual life, nevertheless find time to gossip and slander.
All wild geese are grey in colour; I have not seen any that were of mixed colour or white. But among domestic geese, there are not only grey but variegated and white ones. Wild geese are the colour of ashes, that is to say, those who keep apart from this world wear the modest garb of penitence. But those who live in towns or villages wear clothes that are more beautiful in colour. The goose, more than any other animal, picks up the scent of a someone happening by, as the discerning man knows of other men by their good or bad reputation, even though they live far away. When, therefore, a goose picks up the scent of a man approaching, it cackles endlessly at night, as when a discerning brother sees in others the negligence that comes with ignorance, it is his duty to call attention to it.
The cackling of geese on the Capitol once helped the Romans, and in our chapter-house daily, when the discerning brother sees evidence of negligence, his warning voice serves to repel the old enemy, the Devil. The cackling of the goose saved the city of Rome from enemy attack; the warning voice of the discerning brother guards the life of his community from disruption by the wicked. Divine providence would not, perhaps, have revealed to us the characteristics of birds, if it had not wanted the knowledge to be of some benefit to us.