Q.85 Which one of the following is a “brood parasite” ?
(A) Pigeon
(B) Sparrow
(C) Goose
(D) Cuckoo

Cuckoo is the brood parasite among the options.

Brood parasitism involves a bird laying eggs in another species’ nest, leaving the host to incubate and raise the offspring without any parental care from the parasite. This strategy saves energy for the parasite but harms the host’s reproductive success. Among the options, only the cuckoo exhibits this obligate behavior.

Option Analysis

• Pigeon (A): Pigeons build their own nests and provide full parental care, incubating eggs and feeding squabs with crop milk. They do not parasitize other species.​

• Sparrow (B): Sparrows construct nests from grass and feathers, with both parents sharing incubation and feeding duties for their chicks. No brood parasitism occurs.​

• Goose (C): Geese are devoted parents that build nests on the ground, with females incubating eggs while males guard, and both rearing goslings to independence.​

• Cuckoo (D): Cuckoos are classic obligate brood parasites; females lay eggs in hosts’ nests (like reed warblers), often mimicking host eggs, and the chick ejects competitors.​

The phenomenon of brood parasite birds captivates biology students preparing for exams like CSIR NET, where questions test knowledge of animal behavior and ecology. A brood parasite lays its eggs in another bird’s nest, forcing the host to raise unrelated offspring—a classic example of interspecific parasitism. This article breaks down the brood parasite question: “Which one of the following is a brood parasite? (A) Pigeon (B) Sparrow (C) Goose (D) Cuckoo,” explaining each option with scientific details.

What is Brood Parasitism?

Brood parasitism is an evolutionary strategy where parasitic birds exploit hosts for incubation and chick-rearing, avoiding nest-building costs. Obligate parasites like cuckoos rely entirely on this; facultative ones occasionally do it. About 1% of bird species, mainly cuckoos and cowbirds, are obligate brood parasites.​

Why Cuckoo is the Brood Parasite

Cuckoos (family Cuculidae) epitomize brood parasitism. Females monitor host nests, lay mimetic eggs (matching size/color), and depart. The hatched chick often kills host eggs via eviction, ensuring sole resources. This boosts cuckoo fitness but devastates hosts.​

Evaluating Other Options

Pigeons, sparrows, and geese lack parasitic traits:

Evolutionary Insights for CSIR NET

Hosts counter with egg rejection or chick recognition, driving a coevolutionary arms race. Cuckoos adapt via mimicry and rapid chick growth. This fits topics like behavioral ecology and evolution in competitive exams.​