Rooks are a species in the corvidae family, that is the same family as crows, ravens and magpies. As such they’re intelligent birds that eat insects, grains and carrion. They can use tools and even make them when necessary. They’re also highly social with a language distinct enough for even humans to tell between different types of calls.
The coolest thing about rooks though is the group. A group of rooks can have many names such as building, parliament and a storytelling (you can bet your pretty little ass that last one struck my fancy). They live in societies and besides the Sandman story that inspired the headline there are multiple legends of rooks gathering in a group where one or two isolated birds will “talk” for a while and after they’re done they all either leave together or the ones in the center will get pecked to death. Some have termed it a trial, and that’s certainly what it seems to be in the case of community transgressors. Neil Gaiman’s story deems it a bird telling a story and getting some swift feedback.