In Honor Ridout’s ‘Cambridge and Stourbridge Fair’, she describes a number of the entertainments, from human freaks to exotic animals, plays and musicians. But,
“A different sort of catastrophe befell an exhibitor of animals when his ostrich died. The loss of so distinctive an exhibit must have been a blow… However, the death provided an opportunity to dissect the bird, and the paper reported the interesting collection of ironware and coins found in its gizzard.”
I have read various stories of birds eating all sorts of strange things, often blamed on the birds’ stupidity or curiosity, but the mention of a gizzard suggests something else. Swans and similar birds do not have teeth, so they have no way to break down their food into small pieces in order to allow digestive enzymes to break them down. In the wild, they swallow small pieces of stone and gravel, which, when squeezed in various directions by the muscles of the gizzard, are able to grind the food down. Such small stones are often passed out of the animal, so need to be replaced, but an animal in captivity had little access to stones etc, so they swallowed whatever they could find that might work. Not such dumb birds after all.