Not to be confused with the confectionary Ptasie mleczko, or "Bird's milk".
Secretion used by some birds to feed their young
A rock pigeon feeding squabs.
Crop milk is a secretion from the lining of the crop of parent birds in some species that is regurgitated to young birds. It is found among all pigeons and doves where it is also referred to as pigeon milk. Crop milk is also secreted from the crop of flamingos and the male emperor penguin,[1][2][3] suggesting independent evolution of this trait.[4] Unlike in mammals where only females produce milk, crop milk is produced by both males and females in pigeons and flamingos; and in penguins, only by the male.[5] Lactation in birds is controlled by prolactin, which is the same hormone that causes lactation in mammals.[6][5] Crop milk is a holocrine secretion, unlike in mammals where milk is an apocrine secretion.[5] Crop milk contains both fat and protein, as with mammalian milk, but unlike mammalian milk, it contains no carbohydrates.[5]
^Levi, Wendell (1977). The Pigeon. Sumter, S.C.: Levi Publishing Co, Inc. ISBN 0-85390-013-2.
^Silver, Rae (1984). "Prolactin and Parenting in the Pigeon Family" (PDF). The Journal of Experimental Zoology. 232 (3): 617–625. doi:10.1002/jez.1402320330. PMID 6394702. Archived from the original (PDF) on 13 September 2016.
^Eraud, C.; Dorie, A.; Jacquet, A.; Faivre, B. (2008). "The crop milk: a potential new route for carotenoid-mediated parental effects" (PDF). Journal of Avian Biology. 39 (2): 247–251. doi:10.1111/j.0908-8857.2008.04053.x.
^Ornithology, British Trust for (2012-08-22). "Crop milk". BTO - British Trust for Ornithology. Retrieved 2023-04-30.
^ abcdAnn M. Ward, Amy Hunt, Mike Maslanka, and Chris Brown, Nutrient Composition Of American Flamingo Crop Milk(PDF){{citation}}: CS1 maint: multiple names: authors list (link)
^Cite error: The named reference Gillespie2012 was invoked but never defined (see the help page).
Cropmilk is a secretion from the lining of the crop of parent birds in some species that is regurgitated to young birds. It is found among all pigeons...
doves—Columbidae—also produce cropmilk (just in the glands lining the crop), which contains less fat and more protein than flamingo cropmilk.) For the first six...
inducing inflammation or activating the complement system. Cropmilk is a secretion from the crop of a bird that is regurgitated to feed their offspring....
young. Mourning doves eat almost exclusively seeds, but the young are fed cropmilk by their parents. In 1731, the English naturalist Mark Catesby described...
provide cropmilk. Contemporary depictions show a large crop, which was probably used to add space for food storage and to produce cropmilk. It has been...
A cash crop, also called profit crop, is an agricultural crop which is grown to sell for profit. It is typically purchased by parties separate from a farm...
bird Gagana produces milk. Whether any of these authors were aware of cropmilk from some species of birds is unknown. Bird's milk was first created in...
and pigeons produce "cropmilk" to feed to their young, secreted by a sloughing of fluid-filled cells from the lining of the crop. Unfledged baby doves...
well known example of nourishing young with secretions of glands is the cropmilk of columbiform birds. As in mammals, this also appears to be directed...
Milk is a white liquid food produced by the mammary glands of mammals and the caecilian Siphonops annulatus. It is the primary source of nutrition for...
to produce "cropmilk" in birds is only found in pigeons, flamingos and male Emperor penguins. The father is able to produce this cropmilk to temporarily...
related pigeons provide cropmilk. The risings on the crop of the female may have covered glands that produced the cropmilk. If the theory is correct...
In adult doves and pigeons, the crop can produce cropmilk to feed newly hatched birds. Certain insects may have a crop or enlarged esophagus. Herbivores...
regurgitation) exclusively on "cropmilk" (also called "pigeon milk" or "pigeon's milk"). The pigeon milk is produced in the crops of both parents in all species...
studies of the composition of cropmilk specific to Ducula. However, in domestic pigeons (Columba livia), the cropmilk is found to contain lipids, proteins...
long-eared owls, and eastern screech owls. Predators of chicks and eggs include milk snakes, coluber constrictors, blue jays, crows, eastern gray squirrels, fox...
invasion into new habitats may also be encouraged by fire. Milk thistle is an adaptive crop with low requirements. It is mainly cultivated as a medicinal...
their crop, an additional digestive organ unique to birds, used for storing excess food; their “infant formula”, of sorts, is thus called “cropmilk”. In...
Coconut milk is an opaque, milky-white liquid extracted from the grated pulp of mature coconuts. The opacity and rich taste of coconut milk are due to...
[unreliable source?] Initially, the squabs are fed by their parents with cropmilk (or when human-raised, an appropriate substitute); some breeds are bred...
a crop, birds use it to temporarily store food. In adult doves and pigeons, the crop can produce cropmilk to feed newly-hatched chicks. cropmilk A secretion...
agriculture, the yield is a measurement of the amount of a crop grown, or product such as wool, meat or milk produced, per unit area of land. The seed ratio is...
Crop rotation is the practice of growing a series of different types of crops in the same area across a sequence of growing seasons. This practice reduces...
second nest while her offspring are still growing in the first nest, fed cropmilk by both parents. Establishing two breeding lines has been suggested as...
their crop or regurgitate it along with food. The pigeon family, flamingos and penguins have adaptations to produce a nutritive fluid called cropmilk that...
a result of the cropmilk they are fed by their parents. This is an extremely rich fluid that is produced in the adult birds' crops during the breeding...
produce a nutritious fluid from glands in their crop to feed their young. Due to their diet, this cropmilk is crimson in color. The first flamingo hatched...
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