Mammals make milk – it’s one of their defining features. But certain birds (including pigeons, doves, and albatrosses) do as well.
It’s called crop milk, and it’s not really much like milk as we know it. Sure, there are similarities (the same hormone triggers its creation) but crop milk is created in the bird’s guts. Specifically, it is shed from the crop, and regurgitated to feed wee baby birds.
It has a consistency similar to soggy cottage cheese. You cannot buy it (yup, I checked), although there are quite a few pigeon breeders out there that would love to get their hands on some.
There is a Polish candy called ptasie mleczko, which translates as “bird’s milk.” But that’s apparently from an old saying that has its origins in Aristophanes’ play The Birds, meaning something impossibly rare and delicious. Bird milk, as it turns out, is a popular topic of Slavic folk tales.