Medieval artefacts discovered in vultures’ nests in Spain

Scientists have discovered an unlikely record of human history deep within layers of bony debris left by generations of bearded vultures and their bone-crunching offspring. They have been carefully preserved by birds over the centuries.

There are only 309 breeding pairs of bearded vultures (Gypaetus beard) who remain in Europe. In the 19th century, they inhabited cavities in rock faces throughout the continent, including in Iberian Peninsula.

All that remains of these now extinct lineages in southern Spain are their nesting sites, or “açanhos”, some of which have remained unoccupied for 130 years.

As , cliffside properties are hard to find. That’s why many birds of prey keep intergenerational nesting sites “in the family” over decades and even centuries.

The cliff caves favored by bearded vultures are valuable. The sheltered and cooler microclimate of these caves provides ideal conditions for keeping the accumulated bone remains cool while the cubs learn to chew them.

But it’s not just the location that vultures value: within this “first-class real estate”, Vulture families accumulate layers of nesting material, collected from the surroundings over the years.

In the new study, recently in Ecologycaves have been shown to do such a good job of preserving nesting material that scientists have recognized, between the layers, treasures of our species.

“Thanks to the solidity of bearded vulture nest structures and their locations in the western Mediterranean, they have functioned as natural museums, conserving historical material in good condition”, praises the team, to Science Alert.

The investigation focused on 12 abandoned bearded vulture nests in southern Spain. The nests were mainly composed of remains of “vulture life”: bones of ungulate animals, providing a detailed record of the meals of vultures — and, consequently, of the animals that inhabited the area — since the Middle Ages.

However, the most exciting and unusual discoveries were those of human origin: several ancient sandals, made from a variety of herbs and branches — the oldest of which, a complete sandal made from esparto rope, was made 674 years ago, in the late 14th century.

The team also found a 151-year-old basket fragment; a crossbow bolt and its wooden shaft; part of a sling made of braided esparto; and a host of other evidence of historical culture.

“Os bearded vultureslike hoarders of human bones and artifacts in caves in the north of the Iberian Peninsula, they provided information about the prehistoric human groups that also lived there”, praises the team.