Hornbills are a group of large, extraordinarily long, curved beaks found in Africa, Asia, and the Pacific Islands. Hornbills have a very peculiar breeding habit, that is, the female will close herself in the hole of the tree during the egg-laying period, leaving only a small opening, and the male is responsible for feeding until the chick grows up and flies out of the nest hole. This behavior is very rare in birds, what exactly is its meaning and function?
First of all, hornbills' burrow-sealing behavior can enhance the relationship between males and females and prevent the occurrence of extramarital mating. Hornbills are monogamous birds, with males and females forming long-term mate relationships. But in nature, extramarital mating is a very common phenomenon because it allows individuals to pass on more genes, or obtain better genes. Both males and females will try to stop each other's attempts to have an extramarital match. By sealing herself in the hole, the female can ensure that her offspring are all male, and it can also cost the male more and have to faithfully take care of himself and his offspring. Male birds can also prevent females from mating with other males by sealing holes, ensuring their own gene transmission. Some studies have found that there are no extramarital matings in the nests of hornbills, indicating that the sealing of holes effectively maintains the loyalty of males and females.
Secondly, hornbills' burrow-sealing behavior can reduce the risk of predation by natural predators and improve the survival rate of offspring. The nest hole of hornbills is generally located high in the trunk of a tree, and the hole is small, making it difficult for other animals to find and enter. The hornbill seals the hole with dirt, leaves, and other materials, leaving only a small opening, which adds to the safety. Females are always in the burrows to protect themselves and their offspring, and males patrol outside to keep out intruders. Some studies have found that the probability of the hornbill's nest eating is very low, much lower than that of other nesting birds, indicating that the sealing behavior effectively protects the life of the hornbill.
Finally, the hornbill's burrow sealing behavior can prevent other hornbills from encroaching on their nests and ensure their reproductive rights. Hornbills do not dig their own holes to build their nests, but only choose natural tree cavities. Due to the large size of hornbills, suitable nest resources are limited in a forest, so hornbills that do not occupy nests often try to invade and destroy the nests of other hornbills. Hornbills seal their holes to better defend themselves against attacks from other hornbills and maintain their territory and nests. Hornbills have been observed to have invaders throughout the breeding season, and males have to spend a lot of time chasing out invaders, and sometimes females will break out of their holes to fight, and then quickly return to their nests to seal the holes. These observations illustrate that the act of sealing the hole can better defend one's nest.
Hornbill burrowing is a unique breeding strategy that strengthens the relationship between males and females, reduces the risk of predation by predators, and prevents other hornbills from encroaching on their nests. This behavior is the result of natural selection and has important implications for the survival and reproduction of hornbills. The burrowing behavior of hornbills also demonstrates the diversity and adaptability of birds, which deserves more attention and research.
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