Okay, so this phrase is a take-off from a classic bumper sticker. But I just couldn't resist posting this interesting, but not psychiatric at all, article which was in the same PNAS issue as the VEGF article.
Cowbirds are one of those bird species that are too lazy to raise their own kin, so they sometimes sneak their own eggs into other species' nests, hoping that the unsuspecting host will raise the birds as their own.
TURNS OUT that after they add the foreign egg, they will hang around to make sure that the new host doesn't dump the imposter. If they do, the connected cowbirds will push the host parents' eggs out of the nest.
Otherwise, if the surrogate parents accept the offer they can't refuse and raise the little calfbirds, then the avian mafioso lets them be. Now that's a made egg.