A 118-year-old painting by a famous explorer has been uncovered in Antarctica. The perfectly preserved watercolour of a tree creeper bird was found hidden among penguin faeces and mould-covered papers in a hut at Cape Adare, Antarctica's most north east peninsula.

It was painted by Dr Edward Wilson, who died with Captain Robert Scott and three others on their return from the South Pole in 1912.

The Antarctic Heritage Trust discovered the watercolour during a restoration project of 1,500 artefacts inside the hut at Cape Adare.

The trust's conservator, Josefin Bergmark-Jimenez, was shocked and elated when she spotted the "gorgeous painting" lying among the wreckage in September last year.

"I got such a fright that I jumped and shut the portfolio again," Bergmark-Jimenez said. "I then took the painting out and couldn't stop looking at it – the colours, the vibrancy, it is such a beautiful piece of work. I couldn't believe it was there."

She said the painting is in such an excellent condition as it had been stored in an "ideal way" – tightly pressed between other sheets of paper in a dark and cold environment that stopped the colours from fading over time.

It is not entirely clear how the painting ended up in the Antarctic hut according to Lizzie Meek, the trust's programme manager for artefact conservation.

She said the most plausible theory is that Wilson painted it while recovering from tuberculosis in Europe, after he returned from his first expedition to the South Pole in 1911. He accompanied Scott on a second expedition in 1912 as a scientist and medical doctor.

The discovery of the painting, labelled 1899 Tree Creeper, was kept a secret until now to allow the conservators to complete their work at Cape Adare.