Can’t find it now, unfortunately, but, a couple or so years ago, I read an article on mixed species groups of birds foraging together ‘speaking’ a common ‘language’ to communicate warnings and suchlike — finches, thrushes, sparrows, whatever … the exact details elude me now.

And, as it wasn’t a specific species’ native ‘language’ … they had to learn it from each other … so, the behaviour didn’t arise ‘instinctively’.