Fascinating artifacts found in the nests of vultures

A professor of prehistory at the University of Cantabria in Santander, Spain conducted a proper archaeological "dig" in the nest of a bearded vulture, excavating methodically downwards through ever-older strata.  The image embedded above shows some of the material that one might expect in a large raptor's nest - mammal and bird bones and teeth, hooves, horns, eggshells, and droppings.  

But there's more (click to embiggen):

The second image shows a collage of items handcrafted by humans, to wit -

A collection of handcrafted materials found in ancient Bearded Vulture nests. (A) Part of an esparto grass slingshot. (B) A detail of a crossbow bolt and its wooden lance. (C) Agobía (Sierra Nevada, Granada), a rough footwear made of several species of grass and twigs, C-14 dated at 674 ± 22 years Before Present (ETH-138982). Agobías typically lasted for a few days of wear and were continuously repaired and replaced by hand by the wearer. (D) A basketry fragment C-14 dated at 151 ± 22 years Before Present (ETH-138980). (E) A piece of sheep leather C-14 dated at 651 ± 22 years Before Present (ETH-138981) with red lines drawn, and (F) a piece of fabric. Scale bars are in centimeters. Photographs: Sergio Couto (A, B, D, and F) and Lucía Agudo Pérez (C and E).

That's why the nest was being excavated by an archaeologist, not a biologist.  "...the most exciting one was a shoe, because the shape is totally identical to ones found in an archaeological site called the Cave of the Bat, which is also in the region where these nest have been found. And those are dating 12,000 years ago. 

The scientific findings are reported in the journal Ecology (not behind a paywall), where it is noted that some raptor nests have been located at the same sites for thousands of years.  And the location of these nests, in caves sheltered from the weather affords optimal conditions for preservation of organic material.

"The study of the material preserved in caves housing ancient Bearded Vulture nests can therefore provide interesting information not only about the feeding ecology of the species but also about historical ethnographic and biocultural conditions."

Note the human footwear they found in the nest was carbon dated to the 13th century. This investigation has only sampled the upper layers so far.  More to come.  Fascinating, and kudos to the investigators for coming up with the investigation.

I first heard about this from my favorite podcast - the CBC's As It Happens (transcript).