Records going back to 2001 show that No. 20 and No. 46 have remained together the whole time, and Halpin said it's likely that they've been together since the flock of Chilean flamingos arrived at Zoo Atlanta in 1987.
There are 57 Phoenicopterus chilensis in the flamingo habitat, just inside the front gates of the zoo, and each is numbered with a red or yellow bracelet.
At the beginning of the mating season in the spring, females in this habitat will separate themselves from the flock, and males will follow them around, performing such rituals as “flagging,” “marching” and “wing salutes.”
Last year No. 20 and No. 46 performed these same rituals, and dutifully built a nest out of mud. Then they skillfully stole an egg from another pair, and guarded it faithfully.
Halpin said eggs, nests and chicks are sometimes kidnapped as a shortcut to parenthood. It’s just something flamingos do. “It’s like a soap opera up there during breeding season,” she said. “There’s fighting, chaos, eggs knocked off nests, nests stolen.”
Last year was particularly rambunctious, but No. 20 and No. 46 persevered. After their chick was born, both adults produced what is called crop milk, a secretion in the bird’s esophagus. It is a reddish, foul-smelling, high-protein substance that the parents regurgitate into the mouth of the chick.
Crop milk is like a flamingo's version of lactation, except it's produced by both males and females. Both No. 20 and No. 46 produced crop milk, and both took turns feeding the chick. After a few months the chick was on his own, eating solid food.
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Zoo Atlanta’s flamingos are a fruitful flock, and lay something like 30 eggs a season. The zoo usually sends some of these to other institutions, where the birds are not as fertile.
This year No. 20 and No. 46 are not raising a chick, and seem to be enjoying their empty nest. “They are just like any of the other pairs,” said Halpin. “They spend time together, they eat together, they walk around the exhibit together. They’re like a normal flamingo pair, except they’re boys.”
Their chick, called No. 50, is independent now, and thriving. Halpin said the couple's success as parents is more important than their gender. "I personally don't care what sex they are, as long as they're doing their job raising their chick. They did an awesome job raising their chick."