A cuckoo bird lays its eggs in the nest of its host bird crow and lets the host incubate them, it is a classical example of:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Brood parasitism
(1) Commensalism — Incorrect. In commensalism one species benefits and the other is neither harmed nor benefited. An orchid growing on a mango branch is an example. Here the crow is harmed, so this is not commensalism.
(2) Brood parasitism — Correct. This is a kind of parasitism: one species benefits and the other is harmed. The cuckoo gets its eggs hatched and raised free. The crow spends its effort on another bird’s young. Over time the cuckoo’s eggs have come to look like the crow’s eggs in size and colour, so the crow does not throw them out.
(3) Amensalism — Incorrect. In amensalism one species is harmed and the other gains nothing. The cuckoo gains here, so this is not amensalism.
(4) Mutualism — Incorrect. In mutualism both species benefit, as in lichens (a fungus and an alga living together). The crow gains nothing.
NCERT Extract:
Population Interactions – “… Brood parasitism in birds is a fascinating example of parasitism in which the parasitic bird lays its eggs in the nest of its host and lets the host incubate them. During the course of evolution, the eggs of the parasitic bird have evolved to resemble the host’s egg in size and colour to reduce the chances of the host bird detecting the foreign eggs and ejecting them from the nest.”