Immediately, you look around for the killdeer babies. You may see one disappearing into the grass or flattening itself on the ground and freezing. Two types of baby birds Baby birds that hatch with their running shoes on are called precocial . Other precocial birds besides killdeer are chickens, ducks, and quail. None of these precocial babies lies in the nest and gets waited on.
Robins are altricial, as are blue jays, cardinals and most other birds.
The hatchlings lie helplessly in their nests, relying utterly on their parents to bring them food and push it down their throats. It's two weeks or more before they mature enough to leave the nest, and even after they leave it, their parents are still feeding them. Precocial birds stay in the egg twice as long as altricial birds, so they have more time to develop. Although adult robins and killdeer are the same size, a killdeer's egg is twice as big as a robin's. There's more nourishment built into the killdeer egg, to sustain the embryo for its longer time in the shell.