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Hornbills' nesting strategy involves the nest protected and hidden, incubating eggs and brooding chicks for about 76 days, during that whole time the mum stays at home and food is provided for the family by the father

93,544 просмотров • 1 год назад •via X (Twitter)

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Parrots care for their chicks in a remarkable way, you know. They do not spoon-feed them. They also have no mammary glands the way mammals do. And yet a chick still grows from a naked, blind, soft-beaked creature into a bird that can fly, mimic, and live a very long life. The secret lies in an organ that seems, at first, to be nothing more than a food pouch: the crop at the base of the neck. A newly hatched parrot belongs to the group of helpless young. It cannot keep itself warm, cannot find food, and certainly cannot crack a seed. If the parents merely brought whole seeds back to the nest, the chick would starve before their eyes. Evolution chose another path: the parents eat first, process the food inside their own bodies, and then regurgitate it. The process begins away from the nest. The father, and later the mother as well, searches for seeds, fruit, flowers, and sometimes insects. The food is swallowed into the crop, an elastic muscular sac in the esophagus. There, saliva, mucus, and body heat turn hard seeds into a warm, mash-like mixture. Cells lining the crop also slough off and mix into the food, adding a thick substance rich in protein and fat, rather like the “crop milk” of pigeons. It is not milk in the mammalian sense, but it is enough for a still-developing digestive system to absorb. Back at the nest, the scene changes completely. The chicks stretch their necks, gape, and call without pause. A parent locks its beak into the chick’s mouth in a crosswise grip, then contracts the crop in rhythm. Food is pumped in bursts. The chick answers with a pumping reflex, opening its throat at the right moment to swallow and closing the glottis so it does not choke. The motion looks rough, but it is extremely precise. This is not vomiting. Vomiting forces stomach contents outward without control. Regurgitation delivers a prepared portion, aimed and timed. In the first days, the work is clearly divided. The mother hardly leaves the nest because she must brood. The father forages, returns, and feeds the mother; she then feeds the chicks. Once the young can regulate their own temperature, both parents go out to forage and both feed the chicks directly. Each return to the nest is not a ceremony. It is a work shift, repeated through the day and, in the earliest stage, sometimes through the night. This way of feeding also explains why parrots lay so few eggs. A clutch is usually only a few. The eggs hatch on different days, so one nest always holds larger chicks with wider gapes. The first-hatched are easily favored. In some species, such as macaws, if a youngest chick hatches several days too late, the parents may feed it less, or even abandon it. That is the cold side of an expensive strategy: invest heavily in each individual, rather than spread care evenly across the brood. As the chicks grow, the meals change. The thick mash of the first days becomes coarser, with pieces of fruit and softened seeds. Near weaning, the parents deliberately space out the feedings. They do not indulge. They push the young to eat on their own, to fly, and to recognize what can be eaten in the wild. This stage lasts weeks to months, depending on the species. Large parrots may still be guided long after they have left the nest.

Nature 🦜and Music 🎶

44,845 просмотров • 2 месяцев назад