I’ve changed three diapers in my life. One belonging to my niece. Another belonging to my nephew and one belonging to a monkey. I’ve done an excellent job of avoiding the task for all of these years but from my limited experience I can offer this advice: Once the baby is changed, get as far away from the dirty diaper as possible.
Birds understand this concept and many species of birds have developed their own style of diaper change in the form of a fecal sac. Newly hatched birds have little control over where they defecate. Feeding stimulates the production of a gelatinous sac from their cloaca, which they soon fill with poop. Parents can then wrap up the sac and carry it away from the nest.
The fecal sac keeps chicks out of their own mess, reduces any stench that might attract hungry predators and eliminates the allure fire ants and other insects might find in investigating a nest. Open air nesters have the benefit of better ventilation and cleansing rains, but tree cavity nesters, such as Tree Swallows (Tachycineta bicolor), Eastern Bluebirds (Sialia sialis) and even Downy Woodpeckers (Picoides pubescens) have a contained space that requires good housekeeping. In a crowded room, I’d be quicker to notice the need for a parent to change their baby’s diaper.
Some bird parents will go so far as to eat their hatchling’s fecal sacs. Fresh from the egg, newborns do not fully digest their food and parents can still glean some nutrition from the leftovers.
While fecal sacs are beneficial to certain species, they have their downsides too. Sacs cost chicks energy since they require proteins to produce them. In areas of high predation, parents have been shown to fly the sacs further from the nest which increases their energy expense to the process.
As the young develop, they have better control over where they poop, reducing the need for fecal sacs. Eventually they can be bribed with a toy tractor if they use the potty. No, wait. That’s my nephew.