Wildlife experts have been stumped by images that appear to show a bird hanging fish out to dry at an Angus nature reserve.
Sticklebacks are common prey for the resident kingfisher at Montrose Basin Visitor Centre and Wildlife Reserve, a territorial bird that kills the fish by striking them against its perch.
This softens their stiff spines and makes them easier to swallow.
However, the bird appears to have gone a step further by using the spines to pin three sticklebacks to its regular branch.
Anna Cheshier, Angus Ranger for the Scottish Wildlife Trust (SWT), said the bird appeared to show “unusual behaviour” in the pictures taken by Ron Mitchell.
She said: “The kingfisher visits the reserve almost every day and can be easily seen from our hide.
“The photographer who took the images didn’t realise what he had captured until he took them into the visitor centre the following day.
“It’s hard to tell if the kingfisher has hung the fish on the branch accidentally or on purpose, but this is really unusual behaviour that no one seems to be able to explain.
“We’d like anyone who has seen anything like this before to get in touch.”
Kingfishers are unmistakable birds due to their iridescent blue and orange colouration.
They are found around lochs, ponds and rivers and rely on clean water to be able to dive for small fish and aquatic insects.
There are around 5,000 breeding pairs of kingfishers in the UK.
The basin is home to a range of winter migrants including wigeon, teal, and greenshank, and is best-known for its massive annual migrations of pink-footed geese.
In September 2016, the first of tens of thousands of pink-footed geese arrived in Angus following a 1,200km migration from Iceland and Greenland, with numbers peaking in October.
A record 85,632 geese were counted at the reserve in 2015.
The SWT is Scotland’s leading nature conservation charity, representing more than 40,000 members who care for wildlife and the natural environment.