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Seven fluffy white Chilean flamingo chicks are on display at a zoo in southwest England for the first time since 2018 — and one is particularly notable for the way it made its entrance. Two male flamingos named Arthur and Curtis successfully hatched an egg together — a first for the Paignton Zoo.
The zoo has had several all-male pairings during past breeding seasons, so the same-sex couple is not an unexpected turn of events, said Pete Smallbones, the zoo’s curator of birds. But the zoo is not sure exactly how the couple acquired the egg.
“It’s likely that this egg became available — unprotected, kind of just left (in a nest) — and then they’ve taken the opportunity,” said Pete Smallbones, the zoo’s curator of birds. “As a bird department, we’re more than aware of how it’s a known thing for flamingos, penguins and other species to have same sex pairings. So, it wasn’t a shock — I suppose it was a slight surprise, just because it wasn’t quite the expected (male and female pairing).”
During breeding season, the couples usually spend more time together and follow each other around the enclosure, but a pairing is confirmed when two birds pick a nest to share, where they will take turns sitting on the mud mound with or without an egg. This year, however, a same-sex pair had an egg to sit on. While two male birds hatching an egg together is notably rare, it has happened a handful of times at other zoos.
The successful hatching between two males highlights the social birds’ innate parental instincts and flexibility, experts say. It also underscores the need for conversation about the near-threatened Chilean flamingos that are declining in the wild and their native home of South America, according to the zoo’s news release. And experts have some theories as to how and why their pairing came to be.
Birds of a feather
Chilean flamingos can be finicky when it comes to breeding. In the wild, observations have shown the species to avoid breeding for up to nine years as the birds wait for weather and environmental conditions to be just right, Smallbones said. But even at the zoo, which provides their preferred mud nests, they often don’t breed every year.
One year at the Paignton Zoo, flamingo eggs laid several weeks too late had to be taken away as the chicks would likely not have thrived in the colder weather conditions, Smallbones said. Avian influenza concerns disrupted another prior breeding season, since the birds were removed from their enclosure as a safety precaution, he added.
Curtis and Arthur’s chick, which does not have a name yet, is almost a month old and appears to be thriving, Smallbones said. “The parents are obviously doing a great job.” The chick has been observed exploring the exhibit with another chick roughly the same age but will still return to Curtis and Arthur for food.
While the two males are the only same-sex pairing the zoo is aware of this breeding season, the zoo could potentially welcome more chicks this year as several eggs are still incubating, according to the news release.
Urge to nest
A number of other zoos have observed same-sex pairings among certain bird species. There are even several egg-hatching success stories, such as in 2007 when the Wildfowl & Wetlands Trust in Gloucestershire entrusted an abandoned egg to two male flamingos, and in 2018 when two male penguins at Sydney’s Sea Life Aquarium also became adopted parents to a chick.
“Being in a same sex pair is a relatively common occurrence in captive flamingos, because of small flock sizes,” said Paul Rose, a biologist and senior lecturer on animal behavior at the University of Exeter. “Actually hatching an egg is more unusual. These two male flamingos were likely very keen to nest but could not attract a female partner and so the same urge to nest brought them together.”
Sometimes, same-sex flamingo pairs have been observed disrupting other nests — as Chilean flamingos nest as a flock — in an attempt to obtain eggs of their own, Rose said.
In the wild, Chilean flamingo flock sizes can be in the hundreds during breeding season, according to Rose. The Paignton Zoo currently has 26 female flamingos and 25 male flamingos in the exhibit, which suggests there are enough females for the males to pair with, Smallbones said. While more research is needed to determine why same-sex bird pairings occur, it is possible that Arthur and Curtis found an egg from a male and female couple that wasn’t being cared for and jumped at the opportunity to tend to it, or they took over another couple’s nest, Smallbones said.
It takes two
Flamingos often have non-breeding partnerships that consist of same-sex associations, according to a June 2020 study led by Rose. The birds tend to be “very particular in who they like to spend their time with, and will actively seek out some birds in a flock and avoid others,” Rose added in an email. “I am not surprised that two male flamingos are successful in raising a chick because of their social flexibility, but I don’t believe it would have been their first choice of breeding partner.”
While same-sex bird couples are recorded more in captivity than in the wild, according to Rose, a number of albatross species — types of seabirds — have more females than males in the population, and occasionally, females will pair together to raise one egg, or both will lay eggs and care for them together, said Kevin McGowan, an ornithologist at the Cornell Lab of Ornithology.
Similar to flamingos, hatching an egg and taking care of an albatross chick requires two dedicated parents, as egg incubation takes as long as 60 days — about 28 days for flamingos — and both parents need to provide food for the chick.
“You can’t do it on your own. So, these birds have figured out how to make it work. It’s in their instincts to want to take care of an egg, however the circumstances,” McGowan said. For Arthur and Curtis, the strong natural instinct to breed was likely the driver for the same-sex pairing. “There is a grand desire to have kids, and these two guys (Arthur and Curtis) figured out how to do it,” McGowan added.
Research on the occurrence of same-sex pairing in the wild could provide more information on the possible adaptive benefits of the behavior, such as if a wild flamingo lost its partner but had an egg to look after, Rose said. “This demonstrates how resourceful animals can be when they are driven to do something a specific time of the year or season.”
