Many avian species have an impressive dietary diversity, but all birds have limited options when feeding their young. Granivorous birds usually feed insect larvae to their young, while carnivores give their chicks flesh. Some birds even feed milk to their young.
Four bird species feed their young with milk. Pigeons and doves produce milk in their crops during the lactation phase and feed it to squabs. Flamingos and emperor penguins can also feed their young with milk, but the specific processes and purposes vary.
Which Birds Feed Their Young With Milk?
Pigeons and doves are the most widespread birds that feed their young with milk, including the following species found in the USA:
- Band-tailed pigeon (Patagioenas fasciata)
- Rock pigeon (Columba livia)
- White-crowned pigeon (Patagioenas leucocephala)
- Mourning dove (Zenaida macroura)
- Common ground dove (Columbina Passerina)
- Eurasian collared-dove (Streptopelia decaocto)
- Inca dove (Columbina Inca)
- White-tipped dove (Leptotila verreauxi)
- White-winged dove (Zenaida Asiatica)
Both female and male pigeons and doves can produce a milk-like secretion during the lactation phase.
Similarly, both female and male flamingos can produce milk in all six subspecies:
- American flamingo (Phoenicopterus ruber), also known as Caribbean flamingo
- Andean flamingo (Phoenicoparrus andinus)
- Chilean flamingo (Phoenicopterus chilensis)
- Greater flamingo (Phoenicopterus roseus)
- James’s flamingo (Phoenicoparrus jamesi), also known as puna flamingo
- Lesser flamingo (Phoeniconaias minor)
The fourth species of bird to feed its young with milk is the emperor penguin (Aptenodytes forsteri).
However, only the male emperor penguin produces a milky secretion, as female emperor penguins don’t produce or secrete any milk.
How Do These Birds Produce and Feed Milk to Their Young?
Although most avian species have breasts, they don’t have any mammalian glands, as birds aren’t mammals.
That means the four birds that feed their young with milk use different processes to produce the milky secretion.
Here are the organs that birds use to produce milk for their babies:
- Doves and pigeons: some cells in the crop
- Flamingos: glands in the upper digestive tract
- Male emperor penguins: in the esophagus
The milky secretion of doves and pigeons is also known as crop milk because of its source.
The crop is a sac-like chamber at the bottom of the esophagus of doves, pigeons, and a few other species, including game birds, and it’s essential for food storage.
Adult doves and pigeons use the crop to eat more food than they can digest.
That’s why these birds can consume a lot of food in the wild in a short period, which limits their exposure to predators.
They can also regurgitate some of the food stored in the crop to feed their young.
This crop has some fluid-filled cells that start producing milk during the lactation phase due to hormonal changes.
Doves and pigeons regurgitate this crop milk and feed their young.
Pigeon milk is richer in protein and fat than mammalian breast milk, whether human mothers or cows.
Dove or pigeon milk is so nutritious that it can enhance the growth rate of chicken chicks by 16% to 38%.
It’s also rich in antioxidants that serve as immunity boosters for baby doves and pigeons, also known as squabs.
The crop stops producing milk after the lactation phase when the hormonal changes are not in play anymore, so doves and pigeons resume using their crop as temporary storage space.
But unlike doves and pigeons, flamingos don’t have a crop in the esophagus.
The greater flamingo and other subspecies produce a milky secretion in the glands that line the entire upper part of their digestive tract.
Flamingo milk doesn’t have as much protein as pigeon or dove milk, but it is rich in fat.
It also has both red and white blood cells.
The male emperor penguin produces a milky secretion in its esophagus to feed a hatchling or chick, but this practice isn’t always necessary.
In contrast, pigeons, doves, and flamingos don’t produce or feed their young with milk as a circumstantial or optional food.
The Purpose of Birds Feeding Their Young With Milk
Doves and pigeons feed their young with milk because these hatchlings don’t eat insects or larvae, which are the primary source of fat and protein.
The immunity-boosting effect of crop milk is a bonus for baby doves and pigeons.
Most squabs feed on milk exclusively from their hatchling stage through the nestling phase.
In a week or so, adult doves and pigeons may feed some seeds to their young.
Squabs don’t switch to an adult’s diet, including insects, until a fortnight or so, which is also when the lactation stops.
Like doves or pigeons, flamingos also feed their young with milk due to compulsion.
Flamingo hatchlings or nestlings don’t have the lamellated bill that their parents do.
These filter feeders or sieve-like beaks enable flamingos to forage and discard the materials they don’t want to eat.
Therefore, immature or juvenile flamingos rely on milk exclusively for around two months or until they have a fully developed bill.
The compulsion for male emperor penguins is slightly different.
If you’ve seen the film Happy Feet (2006), you know that the female emperor penguins spend their winter in the ocean, fishing and feeding.
The males incubate the eggs for around two months through Antarctic winters.
The females may return in time and regurgitate some fish to feed the hatchlings.
But if a mother penguin doesn’t return by the time an egg hatches and the newborn needs food, the father has to feed it with the milky secretion produced in his esophagus.
However, this milk-based diet is temporary and circumstantial, and the hatchling may not need the milk if the mother returns in time.
Thereafter, both the parents head out to the sea alternately to hunt and bring fish back for the baby penguin until it has grown to fend for itself.
You are unlikely to find an abandoned or orphaned flamingo and emperor penguin here.
But you might find baby doves or pigeons and wonder what you should feed them.
Consider powdered baby bird foods that you can mix with warm water and hand-feed immature doves and pigeons.
Morning Bird First Formula (available on Amazon.com) is a nutritious option.
This powder formula has a fruity flavor and can also help malnourished and wounded birds.
Baby doves and pigeons will benefit from this baby bird formula’s protein content and other nutrients, including but not limited to:
- More than a dozen amino acids.
- Probiotics and digestive enzymes.
- Several minerals and vitamins.
- Vegetable fat and carbohydrates.