Across their range, Common Ravens (Corvus corax) are quite precise when replying contact calls

An essential signal for social animals is to establish presence or absence of conspecifics. This investigation looked for instances of the Common Raven contact call "aww" [ɒ:] being answered by one or more other ravens at a distance. The data was gleaned from the entirety of raven recordings -- 5435 recordings, mostly audio, but also audio with video -- held by the Cornell Lab of Ornithology’s Macaulay Library, from 1954 Manitoba to 2022 Morocco. The main finding was ravens sent from 1 to 6 “aww”, and replying ravens tended, to a statistically significant degree, to match this number. This precision suggests not only a strong awareness of quantity of sounds, but the raven's awareness of the minds of its fellow ravens.