AYESHA RASCOE, HOST:
What's the oldest piece of clothing in your closet? Maybe a hand-me-down hat, a jacket from your high school football days. How about a 675-year-old shoe?
ANTONI MARGALIDA: (Through interpreter) It's a sandal made of grass rope that has been kept in great conditions. It's as if it's been preserved in a time capsule in a well-protected closet.
RASCOE: Antoni Margalida is an ecologist with the Spanish National Research Council. That time capsule he mentioned is the nest of a bearded vulture high in the mountains of southern Spain. For more than a decade, Margalida and other researchers have been studying the nests of these endangered raptors. In a recent study published in the journal Ecology, they uncovered a surprising trait about the bird. It's an incredible collector and archiver of things made by humans.
MARGALIDA: (Through interpreter) We found remains of an old sandal, the tip of an old spear and a piece of painted leather. We were not expecting to see them in such good conditions.
RASCOE: The vultures built their nest inside mountain caves, and generations of the birds reused the nest - sometimes for hundreds of years. The high-up caves are perfect for keeping baby birds safe. And the stable temperature and humidity inside preserves things like shoes and bits of cloth, likely used to build the nest.
MARGALIDA: (Through interpreter) It's like nature's museum. And when we dated some of the objects, we could see they were from the 13th century. That was very surprising.
RASCOE: But most of what they found in the nest were bits of bone. Bearded vultures are scavengers, and bones make up most of their diet. In Spanish, they're called quebrantahuesos. It means bone-breakers. They were mercilessly hunted to extinction in much of Europe. The Spanish government even paid people to hunt them up until the 1950s. Margalida says studying the birds' abandoned nest can teach us about ecology and human history.
MARGALIDA: (Through interpreter) Everything we have found will provide us with a picture of human customs of that era. The biology is also very interesting. What did the species eat? Where did it raise its young?
RASCOE: Margalida says the biggest challenge so far isn't finding the nest or rappelling down mountainsides to the remote caves. It's getting funding. Bone-breakers are maybe not the most charismatic wild animals. But Margalida hopes that with all the attention this latest study is getting, there'll be more appreciation for Europe's most endangered vulture.
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