These three charismatic birds are the only ones on earth to produce food for their hatchlings. It is called crop milk and they make it in a thing called a crop which is located in the digestive system. Feeding is beak-to-beak. Crop milk is semi solid and in flamingos, it is red, because the pigment from their feathers all goes in, so eventually turn white.

Hetero flamingos and pigeon couples share this task between them. But only male penguins have the ability.

I’m likely the last one here to learn this.

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