Bat
Microbats make use of magnetoreception, in that they have a high sensitivity to the Earth's magnetic field, as birds do. Microbats use a polarity-based compass, meaning that they differentiate north from south, unlike birds, which use the strength of the magnetic field to differentiate latitudes, which may be used in long-distance travel. The mechanism is unknown but may involve magnetite particles.
Charles F. Hockett
While there have been studies attempting to disprove Chomsky, Marcus states that, "An intriguing possibility is that the capacity to recognize recursion might be found only in species that can acquire new patterns of vocalization, for example, songbirds, humans and perhaps some cetaceans." This is in response to a study performed by psychologist Timothy Gentner of the University of California at San Diego. Gentner's study found that starling songbirds use recursive grammar to identify “odd” statements within a given “song.” However, the study does not necessarily debunk Chomsky's observation because it has not yet been proven that songbirds have the semantic ability to generalize from patterns.