You sound familiar: carrion crows can differentiate between the calls of known and unknown heterospecifics

Wild birds recognize individual humans: experiments on magpies, Pica pica

(2011) Won Young Lee et al.   ANIMAL COGNITION

Recognition of faces of known individuals in two lemur species (Eulemur fulvus and E. macaco)

(2010) L. Marechal et al.   ANIMAL BEHAVIOUR

Pigeons can discriminate group mates from strangers using the concept of familiarity

(2010) Anna Wilkinson et al.   ANIMAL BEHAVIOUR

Lasting recognition of threatening people by wild American crows

(2010) John M. Marzluff et al.   ANIMAL BEHAVIOUR

Comparing responses of four ungulate species to playbacks of baboon alarm calls

(2010) Dawn M. Kitchen et al.   ANIMAL COGNITION

Individual Recognition Affects Aggression and Dominance Relations in Rainbow Trout, Oncorhynchus mykiss

(2010) Jörgen I. Johnsson   ETHOLOGY

Eavesdropping on other species: mutual interspecific understanding of urgency information in avian alarm calls

(2009) Pamela M. Fallow et al.   ANIMAL BEHAVIOUR

An avian eavesdropping network: alarm signal reliability and heterospecific response

(2009) R. D. Magrath et al.   BEHAVIORAL ECOLOGY

Urban mockingbirds quickly learn to identify individual humans

(2009) D. J. Levey et al.   PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

Heterospecific eavesdropping in a nonsocial species

(2008) Amanda J. Lea et al.   BEHAVIORAL ECOLOGY

Recognition of other species' aerial alarm calls: speaking the same language or learning another?

(2008) R. D Magrath et al.   PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES