Today this French-based term isn’t about a tableau for the birth of Jesus, or a British daycare or nursery. This is about animal behavior and the communal care and raising of young. This is a behavior that is exhibited by some bird species, particularly aquatic-based birds such as ducks, geese, eiders, penguins, and cormorants.
So, how does this even happen? Well, in some cases it’s just parents feeding the wrong kid, like in the case of cliff swallows who are colonial nesters. In other cases, there could be a territory dispute between females with young in tow, and a mix-up of children happens, and they end up with a different mother than they arrived with. However, sometimes it’s just moms teaming up and taking the “it takes a village” approach to parenting. Sometimes even non-breeding females will assist with the care of the young. I observed an example of a creche in D.C. when I was in town for the National Geographic BioBlitz, when a female Mallard had three ducklings in tow, and one of them was decidedly younger than the other two (not pictured). A National Park Service ranger informed me that it’s very common in the Constitutional Gardens to see that sort of thing, and that it was probably poor parenting on the other hen’s part that led to the hen I saw with the mixed-ages young.
So, this is mostly a bird behavior, but there are mammals, such as humans (ever drop know a kid dropped off to a daycare center?) and lions, that exhibit this behavior. It’s pretty cool to see instances of what could be considered adoption and/or daycare in species outside of Homo sapiens.
A little more information and examples: