Osprey EJ has still to appear at Loch Garten in Cairngorms
Conservationists say they have not yet given up hope that one of Scotland's best-known ospreys will return to a nest in the Highlands for a 16th season.
EJ is the most successful breeding female osprey at Loch Garten, an RSPB Scotland reserve near Boat of Garten in the Cairngorms.
Ospreys migrate to Scotland from west Africa to breed.
Until now, EJ has always returned to Loch Garten by 4 April.
Over previous seasons, 25 of EJ's chicks have fledged.
The raptor, which is nearly 22 years old, is not only known for her breeding success. She has also gained fame for the adversities that she has overcome in previous seasons.
In 2017, she refused to leave her clutch of eggs after they were buried under snow.
Another season saw EJ forced to defend her nest against a rival female.
Reserve staff monitoring CCTV images watched as EJ's eggs rolled around the nest while the pair scuffled.
EJ has also had to defend her nest from crows, buzzards, a white-tailed sea eagle and a hungry pine marten.
Back in 2007, EJ incubated two separate clutches to rival males but they all perished.
And in 2015, a jealous mate kicked eggs that EJ had laid after breeding with another male bird out of the nest.
An RSPB Scotland spokeswoman said: "We've not given up hope on EJ yet, but of course the longer we wait, the less likely it becomes that she'll return.
"Until we get another female taking control of the Loch Garten nest, we're not saying she's not coming back.
"Of course, given her age - she's due to turn 22 this year - the chances are stacked against her."
The spokeswoman said recent cold temperatures and wintry weather appeared to have delayed ospreys' journeys to the Highlands.
She added: "If EJ doesn't return it'll be a sad event. She's part of the fabric at Loch Garten and has been our most productive female.
"But the beauty of the Loch Garten nest is that it's osprey prime real estate.
"The nest site has been occupied for 60 years and the natural order of things is for another osprey to move in and take over the territory when it's vacated, so if that happens and when it happens, we'll have a brand new osprey to get to know and no doubt, become attached to."