In the 'soap opera' tale of Decorah eagles, what role will 'stepdad' play in the future?

The first sign of alarm came as mom sat high atop a tree branch crying out for her partner.

Her desperate, high-pitched call, called a peal, was heard across the scenic Trout Creek valley near Decorah. The bald eagle's mate for nearly a decade had disappeared after an April snow storm. And it was unlike him to be gone: he faithfully took turns with mom guarding their 70-foot high nest and feeding their three budding young.

"It was really kind of heartbreaking," said Amy Ries, who works at the Raptor Resource Project. "She kept calling out for dad and he was not answering."

For all of mom's distress, the disappearance sent shock waves across the country and the globe, as thousands of faithful followers realized something had turned terribly wrong for the idyllic eagle family of five.

This is no ordinary eagle's nest.

The Decorah eagles have been known across the world since the Raptor Resource Project first turned on a live webcam in 2007.

The live stream has offered the world nature's version of reality television: capturing the intimacy of everyday life for the birds.

WATCH: Live video from the Decorah eagles' nest

Crystal-clear cameras capture everything from the monotony of napping and pooping to big firsts like eaglets hatching out of their shells or fledging the nest for the first time. But they also bear witness to the brutality of nature, showing dramatic scenes like 2015's rumble with a pair of great horned owls who challenged the eagles for their nest.

But for the last week, the only story line that has mattered has been the loss of Decorah Dad, who was last seen April 18. Mom has certainly stepped up, ably guarding the nest, hunting and feeding her young on her own — duties normally shared between two parents.

And now, after eagle experts warned their followers that he is likely gone forever, all eyes are another male eagle who has arrived on the scene.

So far, his motives remain unknown: he could swoop in and gobble up mom's three eaglets. Or he could inch his way in, pairing up with the matriarch and eventually playing the role of parent.

Already, the online community has dubbed him "stepdad" as eagle enthusiasts watch the will-they-or-won't-they drama unfold on their screens.

"It's like a soap opera, but a good soap opera," said John Howe, executive director of the Raptor Resource Project. "It's watching what these eagles do, not the stuff they do on soap operas."

Eagle fans mourn dad: 'Think of good memories.'

While other eagle cam operators have given their subjects playful names like Romeo and Juliet, the Raptor Resource Project has been wary of such practices. That can lead people to project their own humanity onto these wild animals, Howe said.

So Decorah's matriarch is named Mom Decorah and the missing male is Dad Decorah. The three eaglets are named simply D29, D30 and D31.

But that hasn't curbed people's attachments to the inhabitants of the nest.

More than 1,500 commented on a Facebook post Thursday to mourn the loss of Dad Decorah. The Raptor Resource Project will hold a memorial on its Facebook page Wednesday. And the group will turn off the chat function that accompanies the eagle cam to give volunteer moderators "a little time of their own."

On the chat last week, users took turns memorializing dad with nice thoughts.

"I liked the way he was so patient with Mom's nestorations," one chatter wrote, "until she left and then he would change things. Or how he did not tolerate the flies and would snap at them. And also the way he always paid extra attention to the littlest one. Think of good memories."

RELATED: Humans won't intervene with baby Decorah eagles after dad went missing

And the throngs of fans often try to interpret the motives of the other male and predict what will happen next.

Said one follower: "Mom gets upset when the new guy gets too far away, she screams for him, you see him quickly come back!! Makes me happy."

Another suggested that his way to mom's heart was through her stomach: "If stepdad wants in the front door he had better start bringing gifts."

But some remain wary. It's still unclear whether the other male might pose some threat to the nest. And Howe says some eagle watchers remain suspicious of his motives. Some commented that they were too distraught over dad's disappearance to continue watching as a new player takes the stage.

"I feel I have been reading a long book and a new character has just been introduced," a follower wrote on the group chat Friday.

'Once you start watching, you can't stop.'

Donna Clarke, a high school teacher in Ohio, has followed Decorah's eagles for some five years. She checks in with the eagles every day.

She loves nature and birds in particular. Her backyard is filled with birdhouses. And she can't get enough of Decorah's eagles and the fuzzy, little eaglets.

"Those babies are fascinating," she said. "Once you start watching, you can't stop."

Clarke sometimes struggles with the brutality of nature: she stepped away for a while when an eaglet on one nest cam got caught up in fishing line and perished in the nest. And she shuddered when Mom Decorah recently brought a baby rabbit into the nest for a meal.

"When I first started watching all of this, I couldn't look at them as animals," she said. "I was looking at them as real babies."

She knew something was wrong as soon as the Decorah patriarch went missing. And she remains suspicious of the other male bird lurking about. She said she'll have a hard time sticking with the nest cam if he pairs up with mom.

"I think a lot of people will get away from that cam for awhile," she said. "Its not going to be easy to look at that bird and know he killed the dad. It will take me a while. But it's nature."

Clarke loves watching the drama of eagle life unfold online. She's seen eaglets hatch. And she's marveled at mom's fishing ability, sometimes catching two at a time.

But she's learned to avoid the humans who narrate the action on the livestream chat.

"I don't need that kind of drama," she said. "I like to watch the birds do their thing."

Eagle stepdad: 'It's an interesting twist to this."

Howe believes the other male, called Unidentified Male Eagle, or UME, is misunderstood.

A panel of eagle experts concluded that he could be responsible for dad's disappearance: conflicts with single eagles are a leading cause of mortality for bald eagles.

Eagle cam followers might be alarmed by mom's calls towards the male. But Howe noted that he is helping mom defend the territory around the nest. And she has been seen soaring alongside him and perched together in a tree.

"Although she has not let him get onto the nest directly," Howe said, "it seems like each day she gets a little more comfortable with him there."

More drama unfolded over the weekend, when observers on the ground spotted a third adult eagle flying around the nest. It locked talons with the unidentified male. The Raptor Resource Project doesn't believe that eagle to be Decorah Dad, but said online "we are certainly keeping our eyes open and learning as we go from this year's version of 'As The Nest Turns'!"

Eagles don't traditionally begin courtship until the fall. For now, Howe said it's anybody's guess what will happen between Mom and the unidentified male.

"When there’s a void to fill, it usually gets filled fairly quickly," he said. "It's an interesting twist to this."

But even without a mate, mom seems to be doing fine. She's keeping watch over the eaglets and keeping them all well fed.

"We’ve got a missing parent," he said. "But we’ve got a very capable female. She hasn't skipped a beat."

And as much as online fans have mourned dad's loss, many more have marveled at mom's ability to simply power through on her own.

"Wow, has she got this down," one wrote on the eagle cam chat. "She is my heroine."

'There are people who say this saved my life.'

The Raptor Resource Project works to preserve falcons, eagles, ospreys, hawks and owls. It creates, improves and maintains more than 50 nests and nest sites.

Aside from the popular Decorah bald eagle nest — which has earned nearly 400 million views online — the nonprofit operates several live cameras, including another live nest cam north of Decorah.

But none compare to the popularity of the main Decorah nest, whose livestream went viral several years ago and has maintained a strong following. While nature can sometimes move at a slow pace, Howe said there's always something worth watching in eagle land.

The livestream's audience is sliced into three main segments.

There are nature enthusiasts who can't get enough of the birds. And there are educators and students who watch the camera in school to learn about the natural world. And many viewers are confined to hospital or nursing home beds.

All are passionate, but the sick and elderly often watch the birds hours on end, Howe said.

"There are people who say this saved my life, I had no reason to live and now I can get up and watch the eagles," Howe said. "We get those kinds of letters and emails."