A nesting crunch sees the true story of 'Avian Sister Wives' unfold on St. Thomas, Ont. porch

Finding a robin's nest on the front porch was nothing new for St. Thomas resident Debra Copeland, but finding a nest shared by two squabbling female robins, eight eggs and a couple visiting male birds was a different story.

During a typical spring, Copeland said she sees no more than five light blue eggs in a robin's nest. That's why she was surprised to see more packed into a brand new nest above her porch light at the end of April, and put up a camera to investigate.

"I was shocked and amazed that by the night, there were two females incubating the nest at the same time," she said, adding that the relationship was tenuous at first.

"At the beginning, you could tell they were very unhappy with one another … They would bite each other's beaks, peck at each other, they'd jump on top of each other to get the other to fly away and sometimes it would work."

"But, I think that these just might be the most stubborn and devoted robin mamas that have ever existed, because neither of them were willing to give up," Copeland said.

After three days of fighting, the two female birds ultimately decided to work together to raise their eggs in the shared nest, she said: they take turns watching and feeding the now-hatched group of babies.

"They rarely squabble. They almost look like they are super bonded and kind of love each other because they snuggle up together in the nest," she said.

The behaviour is unusual for robins but not completely unheard of, according to Ontario Nature executive director Andres Jimenez.

"If you think about this from the lens of having a very desirable male in a fantastic territory where there are few places for a safe nest, it would help the females be inclined to share a nest," said Jimenez. "I refer to it as a housing crisis."

While the mother birds on Copeland's porch share the parenting duties, Jimenez said nest "helpers" – the term for birds who assist in raising babies who are not necessarily their own offspring – can operate in different ways in different relationships.

"There are birds who did not lay eggs and help, there are instances of a dove and robin laying eggs in the say nest and feeding all the chicks … there are instances of some birds who delay their reproduction to help their parents into rearing other birds when they come back from migration," he said. "Everything is possible."

"[Robins] are adaptable, they're flexible, they solve problems in ways that we still cannot fully explain," Jimenez said.

On Copeland's porch, ultimately six of the eggs hatched, though one of the fledglings was pushed out of the nest and died over the long weekend, leaving the moms with five birds to raise.

"It's a very, very tight living situation. They are quite packed in there … you can see them flapping their wings and trying to push each other around so they can get space," Copeland said, adding that she built a soft landing pad under the nest and frequently checks to make sure no others fall out.

There is also a male bird or two in the picture, Copeland said. While she is unsure exactly how many males are involved, she has recorded at least one bringing back food to the co-habiting females.

"I have a pretty strong feeling that there's actually two whole couples, so that makes it even more interesting because it's not like one male has babies with both of them, it means for some reason the females were prompted to share this nest," she said. "It's like one big family stuck in one house."

The story has gained traction in bird watching Facebook groups, with hundreds of people interacting with Copeland's daily photos, videos and updates from the nest.

"I think it's so unique, different and odd, and there's lots of questions, so it makes people want to puzzle it out," Copeland said. "I think we also want to see them succeed. We want to see them be in a situation that's difficult or hard, and we are all rooting for them to do well."

LISTEN | Hear what it's like to house this large robin family