Organ Producing Pigeon Milk

'Pigeon Milk' is a white slimy substance produced by the:

Correct Answer: Crop

'Pigeon milk' is a white slimy substance produced by the crop of pigeons (specifically crop-lining cells of both male and female pigeons). It is NOT produced by a mammary gland — birds do not have mammary glands.

What is Pigeon Milk?

• It is a crop secretion (not true milk) rich in protein and fat.
• Produced under the influence of the hormone prolactin (same hormone that stimulates mammary milk production in mammals).
• Both parent pigeons (male and female) produce it to feed squabs (baby pigeons) during the first few days after hatching.
• It is analogous to mammalian milk in function but differs in origin.

Mammary Gland Facts

• Mammary glands are modified sudoriferous (sweat) glands — ectodermal in origin.
• Mammary glands are innervated only with sympathetic fibres; parasympathetic fibres are absent in udder.

Why Other Options Are Wrong

• Mammary gland → birds do not have mammary glands.
• Gizzard → a muscular digestive organ; not involved in milk-like secretion.
• Both crop and mammary gland → incorrect; only the crop is involved.