Skeletal remains found in a cave with a bird’s skull in its mouth and another next to its cheek have been identified as belonging to a 12-year-old Scandinavian girl from the 17th century.

Coming across human remains buried in odd circumstances is, to some extent, part of an anthropologist’s job description — and usually they’re able to suss out the reason why the remains are buried the way they are. However, a skeleton in Poland has created a bit of a conundrum.

Found in Tunel Wielki Cave, Sąspowska Valley, Kraków-Częstochowa Upland, the bones of a child buried in a shallow grave are thought to have been buried there roughly two centuries ago.

The unusual thing is that the only other human bones in the cave were over four millennia old, which suggests it wasn’t a spot regularly used for burials at the time the child died.

According to researchers at the Insтιтute of Archaeology in Warsaw, it’s the only discovery of a modern human skeleton in a cave in this region — and the plot thickened further from there.

The archaeologists also found the skull of a chaffinch bird in the child’s mouth as well as another beside its cheek. They’re currently struggling to get their heads around why the skulls were buried with the child’s remains.

Technically, the skeleton isn’t fresh; the bones were actually discovered around 50 years ago when the caves were excavated.

However, almost immediately, the remains were placed in storage without ever having been ᴀssessed and examined properly.

“When we opened another dusty box from an old research project, we found small child’s bones,” said archaeologist Małgorzata Kot from the University of Warsaw in a report by Science in Poland, “their discoverer, professor Waldemar Chmielewski, never published the details of this find, he only included a pH๏τograph of it in a book published in the 1980s.”

“This practice is not known among the ethnologists we have asked for opinions,” said Kot, “it remains a mystery why the child was buried in a cave in this way, not in a cemetery in a nearby village.”

Unfortunately, there’s now a serious problem for the team in terms of finding out what happened to the child — the skull was sent over to anthropologists in Wrocław straight after excavation and has gone missing.

“Unfortunately, the child’s skull is not in the possession of the University of Warsaw, but after the excavations it fell directly into the hands of anthropologists in Wrocław,” said Kot.

That said, analysis recently carried out on what was left of the child’s remains is promising and may provide more clues about the bizarre find.

Radiocarbon dating shows the child is about ten years old and was buried very close to the surface in one of the cave’s two chambers — and the results also suggest that the child suffered from malnutrition.