Vultures Stashed Sandals and Other Archaeological Artifacts in Their Nests Around 675 Years Ago
Most archaeologists are human — most, though not all, apparently. According to a new analysis in Ecology, the bearded vulture (Gypaetus barbatus) served an archaeological role in southern Spain for hundreds of years, accumulating anthropogenic objects and stashing them inside their nests.
The analysis suggests that these nests are thus “natural museums,” packed with artifacts that can provide important information about the past. In fact, the material incorporated inside these nests can tell us all about the species’ ecology, as well as its historical environment, including its access to human-made materials, hundreds of years ago.
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These Avian Archaeologists Collected Oddities
The bearded vulture is threatened today, but centuries ago, the species was widespread in the mountains of Europe and the mountains of Iberia, in particular. There, the vultures constructed their nests in the cliffsides, stashing sticks and other materials inside the crevices and caves among the mountaintops. The sheltered conditions of these caverns meant that their nests stuck around, surviving across decades and centuries, being reused by generation after generation of birds.
Bearded vulture nests, often located in caves or protected rock ledges, offer ideal microclimatic conditions that preserve both the bone remains they bring to feed their chicks and the nest-building material.
(Image Credit: Sergio Couto)
The nests themselves were made mostly with twigs and grasses, muddled together with a mixture of other objects, including bones, feathers, and fur, as well as cloth, string, and other human-made materials. So, what oddities have been built inside these nests, and how long have they been hidden there?
To find out, the authors of the analysis set out to study the items in historical bearded vulture nests, assessing the birds’ accumulation of natural and anthropogenic artifacts and their reuse of their shelters over time. Turning to southern Spain, an area where the species disappeared around 130 to 70 years ago, the team identified around 50 nests and investigated 12 of them, finding 2,483 objects in total.
Across all 12 nests, 2,117 bone fragments and 43 eggshell fragments were detected, revealing the birds’ diet and reproduction. With that, 226 anthropogenic items were described, including 129 fabric objects, 72 leather objects, 25 esparto grass objects, and 11 hair objects. While the natural items indicated the presence of all sorts of animals in southern Spain, including a smattering of bird and mammal species, the anthropogenic artifacts provided a peek into the material traditions that were present throughout the Iberian Peninsula.
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A Source for Future Scientific Study?
The items themselves were identified in layers, a lot like the artifacts at an archeological site, separated by strata, or levels of sediment. This stratigraphic approach, combined with carbon-14 (C-14) analysis, allowed the team to pinpoint the nests’ age and to start to piece together the timeframe of their occupation, thus providing important insights into the birds’ ecological and historical environment.
Among the handmade objects found in bearded vulture nests, the scientists found part of an esparto sling, a fragment of basketry, a piece of sheepskin with red lines painted on it, and, surprisingly, a crossbow bolt, which the bird may have used as nesting material or collected from prey.
(Image Credits: Photographs: Sergio Couto (A, B, D, and F) and Lucía Agudo Pérez (C and E))
For instance, a sandal from one of the nests was dated to around 675 years ago, while a shred of a painted sheepskin from the same nest was dated to around 25 years after that. Other objects included a strap from a sling, a scrap from a basket, a strip from a sheet of fabric, and a bolt from a crossbow, with the fragment of basketry being around 150 years old.
The age of the objects suggests that some of the nests had been occupied by vultures for decades, while the state of preservation of the objects indicates that the nests themselves, sheltered in the cliffside, had acted as a sort of natural shield, maintaining a stable temperature and humidity, or “microclimate,” that helped the natural and anthropogenic items survive.
According to the team, the results stress that the bearded vulture served as an important accumulator, collecting items of ecological and historical importance that could color our perception of the past, hundreds of years later. While the bird itself isn’t seen in southern Spain today, it’s played a surprising part in the preservation of Iberia’s past, picking items and preserving them for future scientists to study.
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