Killdeer nest on open ground, often on gravel. They may use a slight depression in the gravel to hold the eggs, but they line it only with a few stones if at all. Since there is no structure to stand out from its surroundings, a killdeer nest blends marvelously into the background, and the speckled eggs look like stones as well. Both parents take turns sitting on the eggs to incubate them as soon as they all have been laid. The killdeer embryos inside the three first-laid three eggs do not start developing while the eggs are sitting out in the cold. But when they feel the warmth of the parent killdeer, all four embryos start developing at the same time. So even though the first-laid egg spends a longer time in the shell than the last-laid, all the chicks have the same development period (24 to 28 days). Although adult robins and killdeer are the same size, a killdeer's egg is twice as big as a robin's, so there is more nourishment in it to sustain the embryo; therefore, a one-day-old killdeer chick is actually two weeks older than a one-day-old robin nestling. They hatch with their eyes open, and as soon as their downy feathers dry, they start scurrying about on their overly-long legs, following their parents and searching the ground for something to eat. They are clumsy at first and can't fly yet, and they need their parents for protection and guidance, but they are a lot closer to independence than most baby birds. Like chickens, ducks, and quail, killdeer chicks are precocial (Latin for "ripened beforehand"); most birds, however, are altricial (from th Greek word meaning "wet nurse") -- the hatchlings are blind, naked, and lie helpless in their nests, relying on their parents to bring them food and push it down their throats. It takes two weeks or more before they are mature enough to leave the nest, and even then their parents feed them. If a potential predator approaches, the chicks hide in the grass or flatten themselves on the ground without moving. Meanwhile, the parent sruggles ahead as tthough it can barely walk, with one or both wings dragging on the ground. When the predator pursues the easy prey, the killdeer manages to stay just out of reach as it leads its pursuer away from the chicks, then will suddenly fly away, jeering a loud "KILL-DEER."
ReplyDeleteKilldeer nest on open ground, often on gravel. They may use a slight depression in the gravel to hold the eggs, but they line it only with a few stones if at all. Since there is no structure to stand out from its surroundings, a killdeer nest blends marvelously into the background, and the speckled eggs look like stones as well. Both parents take turns sitting on the eggs to incubate them as soon as they all have been laid. The killdeer embryos inside the three first-laid three eggs do not start developing while the eggs are sitting out in the cold. But when they feel the warmth of the parent killdeer, all four embryos start developing at the same time. So even though the first-laid egg spends a longer time in the shell than the last-laid, all the chicks have the same development period (24 to 28 days). Although adult robins and killdeer are the same size, a killdeer's egg is twice as big as a robin's, so there is more nourishment in it to sustain the embryo; therefore, a one-day-old killdeer chick is actually two weeks older than a one-day-old robin nestling. They hatch with their eyes open, and as soon as their downy feathers dry, they start scurrying about on their overly-long legs, following their parents and searching the ground for something to eat. They are clumsy at first and can't fly yet, and they need their parents for protection and guidance, but they are a lot closer to independence than most baby birds. Like chickens, ducks, and quail, killdeer chicks are precocial (Latin for "ripened beforehand"); most birds, however, are altricial (from th Greek word meaning "wet nurse") -- the hatchlings are blind, naked, and lie helpless in their nests, relying on their parents to bring them food and push it down their throats. It takes two weeks or more before they are mature enough to leave the nest, and even then their parents feed them. If a potential predator approaches, the chicks hide in the grass or flatten themselves on the ground without moving. Meanwhile, the parent sruggles ahead as tthough it can barely walk, with one or both wings dragging on the ground. When the predator pursues the easy prey, the killdeer manages to stay just out of reach as it leads its pursuer away from the chicks, then will suddenly fly away, jeering a loud "KILL-DEER."