The chick was just five weeks old and unable to properly walk or fly when the disaster happened after a storm last spring.
Conservationist Dave Sexton, Mull officer for RSPB Scotland, was deeply concerned when he saw the damage – and no sign of the parent birds or their offspring – during his routine patrols along the coastline.
He said: “To my horror, looking through a telescope from afar, I could see the nest was hanging vertically in the tree as the supporting branches below had broken off after a severe spring gale.
“I raced up to the nest area, expecting to find the chick either dead underneath or injured and helpless on the ground. There was no sign of the chick and no alarm-calling adult birds to suggest it was nearby or alive.
“I did a thorough search and concluded the chick must have either managed to get itself into the long bracken and died, or that it may have been eaten.”
But he never totally gave up hope and continued to look out for the eagle family.
His patience was eventually rewarded, first with a few fleeting sightings of adult birds displaying behaviour that could suggest they were caring for young. Then finally he got proof.
“In the still air I could clearly hear the food-begging calls of a chick,” he said.
“The adult sea eagle kept looking down, so I tilted the telescope towards the base of the crag and sitting there, shouting its head off at the parent, was the chick.
“I couldn’t believe my eyes. It must have used all its strength to slowly shuffle its way uphill, through bracken and over rocks.
“It would have been fed on the ground by the parents, getting stronger and more mobile by the day, until several weeks later it reached the top of the wood and out onto open ground.
“As I watched, it even started to exercise its wings.
“It was just incredible that it had survived all the trauma and ordeal of its nest collapsing, and thanks to the fantastic efforts of its ever-attentive parents had made it this far. Remarkable.”
He didn’t see the “miracle chick” again for a long time, but hoped it had continued to thrive despite its unusual upbringing. Then, late last summer, when the fledgling would have been due to take its maiden flight, he was again rewarded.
“I climbed to a high vantage point and waited. After several hours I heard that call again, and a few moments later the young eagle soared into view, closely followed by the female and then the male.
“For a couple of minutes all three circled lazily in the late summer sun, the perfect family picture, and then slowly drifted out of sight.
“It was one of the most satisfying experiences of my life and testament to their incredible ability to survive in this harsh and unforgiving landscape.”
But the story doesn’t end there. New pictures have emerged of the chick out hunting with its parents, taken by a local wildlife enthusiast.
Amanda and David “Bodie” Fergusson spend a lot of time out on the sea as part of their daily work running Lochaline Dive Boat Charters, based across from Mull on the mainland.
Mrs Fergusson says the local sea eagles seem to recognise their boat, and will swoop down to snatch up any fish thrown to them.
“I love seeing them,” she said. “I can’t get enough of them.”
She has even witnessed one of the birds grabbing a fish that was so big and heavy it couldn’t take off and nearly drowned. But with much flapping and paddling it finally managed to struggle ashore with its quarry.
She didn’t manage to photograph the spectacle but she did unwittingly capture pictures of the “miracle” chick months after its nest collapse ordeal.
She also snapped a rare interaction between a nosey lamb and one of the adult birds, where the lamb approached and “nudged” the predator.
Although the boat trips have been on hold during lockdown, she continues to enjoy watching the local wildlife, which has seemed more prolific with barely any cars on the road due to coronavirus restrictions and fewer people around.
Sea eagles – also known as white-tailed eagles – are the biggest birds of prey in the UK, earning them the nickname “flying barn doors”.
The species was originally found across Scotland and the UK, but became extinct in 1918 when the last known bird was shot in Shetland.
Today’s population stems from a successful reintroduction project that began in 1975 using birds taken from Norway.
Sea eagles are now a major wildlife tourism attraction in Scotland, particularly on Mull, which has become known as Eagle Island.