Boston sure loves its swans.
Each spring when they return to the Public Garden the Mayor leads a grand parade and hundreds of kids arrive dressed as swans and ducks. They even nicknamed one swan duo that never leaves each other's side "Romeo and Juliet."
Only, it turns out neither swan is Romeo -- they are both female.
This happy same-sex couple exhibits all the behaviors of two heterosexual swans that have mated for life, said Dr. Frank Beall, general curator Zoo New England, where the swans live in the fall and winter.
"They build nests together, incubate eggs together and defend their territory together," he said. "They're deeply bonded."
The swans might never have been outed as a same-sex couple if it hadn't been for their eggs -- and The Boston Globe newspaper.
The swans have laid eggs for the past two years, taking turns incubating the eggs and guarding them. An excited public awaited baby swans, but the eggs never hatched.
"Park officials were suspicious and sent the eggs to be tested," said Donavan Slack, who wrote about the swans for the Globe.
Tests showed the eggs hadn't been fertilized. They would have been in the presence of a male. That raised further questions.
It can be difficult to tell a swan's gender, so Beall's team at the zoo gave them an exam and determined these swans were both girls. The Parks Department didn't tip off the public until the Globe asked for the results and then published a story.
Reactions from Bostonians have been mixed. Some are calling them a symbol of acceptance and tolerance, with a nod to the fact that Massachusettes is the first state to legalize gay marriage. Others are calling for the city to buy "real Romeos," male swans for the girls.
As of now, the Parks Department plans to do no such thing.
"Swans do mate for life," Beall said. "If you introduce a male at this point, he will likely be driven off."
The only way to get these swans to mate with a male would be to "stage a fake death" and trick the swans into believing the other had died, Beall said. Swans that have lost a mate do take another, so if one of the swans were to be introduced to a male swan under those circumstances, they would pair off with him.
If these swans had been around male swans to begin with, they probably would not have decided to mate with each other, according to Beall.
"Here you have two birds of the same gender who gravitated toward each other," he said. "They had no other chioce. If there were more birds, both male and female, perhaps there would be another story."
The swans are about 6 years old but they've only lived at the Public Garden for about two years.
In 1989, the city of Boston reinstituted an old tradition of welcoming swans into the Public Garden each spring until they go back to the zoo for the winter.
Boston's first group of swans included four males and females. When they died, the current swan couple was brought in. The breeder who sold them to Public Garden said that they were both females from the outset, but once the swans laid eggs and started incubating them, hopes were raised that perhaps one of them was a male after all.
Beall has observed that often with same-sex swan couples, one will take on characteristics of the opposite sex, playing the role of the opposite gender. The same is true with these swans, he said.
Perhaps people were eager to believe these swans, which have a lifespan of between 20 to 30 years, were a male-female couple for the romance factor.
The swans are of a species called "mute swans," which don't make noise except for an occasional hissing if they're angry. Mute swans are the "lovebirds" of swans. Pairs of mute swans often face each other and touch bills -- making what appears to be a heart-shape. That -- plus the fact that they mate for life -- is why they're so closely associated with love and romance.