In the role of motherhood, the cuckoo does not incubate its eggs but relies on others to do so. The offspring of cuckoos strike down their competition from the very moment they see the light of day.
The rainy season is a wonderful time for new life to begin its revival in the tropical rainforests. The plants don fresh green coats, and somewhere in the forest, in the wetlands, every patch of reeds and bulrushes stretches out to grow. This is the ideal nesting site for some species of marsh warblers belonging to the genus Locustella. It is also the right moment for the cuckoo to fulfill its “brood parasitism”, a strategy passed down from its ancestors in the struggle for survival.
In the natural world, every creature is born and nurtured by its parents, but cuckoos lie outside that rule. Instead of building nests, laying eggs, incubating, and caring for their young, cuckoos typically seek out the nests of warblers to “deposit” their eggs. This is known as the “cuckoo egg-laying strategy.”
First, a female cuckoo finds a warbler’s nest that already contains eggs and rewards herself with one of its eggs. After gorging herself, that mother lays another egg in the nest. This egg is nearly the same size as the warbler’s eggs and has a very similar pattern, causing the warbler pair to believe it is one of their own.
A mother warbler brings food to the cuckoo chick Endynamis scolopacea. (Photo: Phùng Mỹ Trung)
After the cuckoo chick hatches in the warbler’s nest, although it is newly hatched and still bare, it quickly demonstrates the prowess of a predator. It uses its muscular strength, wings, and back to push the newly hatched warbler and the remaining eggs out of the nest. Its scheme is to monopolize the food resources meant for the warbler’s brood.
Once it has fulfilled its “mission”, the cuckoo grows rapidly and spends its days demanding food from the small warbler parents. To satisfy the gluttonous needs of their much larger foster chick, the warbler couple must work hard to find food.
When the cuckoo has grown enough feathers and is ready to fly, it will leave, abandoning the nurturing parents. One day, it may return to lay its eggs in the same nest of its “foster parents.” The phenomenon of “brood parasitism” among cuckoos is considered peculiar in the natural world.
The mother cuckoo cannot feed her young because she primarily eats caterpillars, including those that are toxic. For fully grown cuckoos, their bodies are immune to the toxins of poisonous caterpillars. However, since the cuckoo chick does not have an immune system yet, consuming toxic caterpillars could be fatal. Thus, the mother cuckoo must rely on other birds to raise her young. This also represents a unique piece in the vivid picture of the struggle for survival and the continuation of species in the wild.
The cuckoo chick cries out and demands food from its “foster parents”. (Photo: Phùng Mỹ Trung)
The cuckoo’s scientific name is Endynamis scolopacea. The male has black plumage with deep blue highlights. The female has pale brown and white mottled feathers. The female’s head is slightly lighter and browner than that of the male. The chick is entirely covered in black down, but after its first molt, it changes to plumage similar to that of the female. The male has reddish feathers for a time before gradually transitioning to adult plumage with red eyes, a grayish-blue bill, a black base of the bill, and slate-gray legs.
Cuckoos are distributed in Thailand, Laos, Cambodia, Vietnam, southeastern China, and Malaysia. In Vietnam, cuckoos are found throughout the lowland and midland regions. During winter, they are rarely seen as most fly south to escape the cold.
Rare moment: An eel tears the throat of a predator while flying in the sky
