Earliest example of animal nest sharing

[Still Waters]

An international team of scientists, including researchers from the University of Southampton, has shown that fossilised eggshells unearthed in western Romania represent the earliest known nest site shared by multiple animals.

The shells -- some complete and others broken into thousands of pieces -- are densely packed and encased in mudstone which formed part of the remains of a bird breeding colony, probably comprising hundreds of seperate nests.

Now in the collections of the Transylvanian Museum Society in Cluj Napoca, Romania, the samples date from the late-Cretaceous period (approx. 70 million years ago) and were discovered near the city of Sebeş in Transylvania by local palaeontologist Mátyás Vremir about nine years ago.

https://www.sciencedaily.com/releases/2019/02/190220103421.htm

[Carnoferox]

http://tetzoo.com/blog/2019/2/17/multi-species-nesting-in-late-cretaceous-europe