Individual recognition and selective response to contact calls in foraging brown-throated conures, Aratinga pertinaxMethodsForaging Group and Overflying Group InteractionsObservations of natural foraging group and overflying group interactionsExperimental playbacksStatistical analysesShort-term Captive StudiesCapture and housingRecording and analysis of short-term captives’ contact callsSexing of the individuals and assignment of individuals to pairsTests for preferential response to mates and group membersStimuli for mate trialsStimuli for group-member trialsStatistical analysesEthical NoteResultsObservational Study: Overflying Group Behaviour When Called ToPlayback Study: Overflying Group Behaviour When Responded ToDo Ecological or Call-based Factors Drive Calling by Foraging Groups?Individual Differences in Contact CallsPreferential Response Trials: Responses to MatesPreferential Response Trials: Responses to Group MembersDiscussionAcknowledgmentsReferencesAvailable online at www.sciencedirect.comIndividual recognition and selective response to contact callsin foraging brown-throated conures, Aratinga pertinaxSUSANNAH C. BUHRMAN-DEEVE R , ELIZABETH A. HOBSON & AARON D. HOBSONDepartment of Neurobiology and Behavior and Lab of Ornithology, Cornell University, Ithaca, New York(Received 17 January 2008; initial acceptance 13 April 2008;final acceptance 24 July 2008; published online 14 September 2008; MS. number: A08-00039)Foraging individuals can benefit from recruiting conspecifics to food sites, but must balance potentialbenefits against increased competition. Foragers in fissionefusion societies may recruit others to foodresources by calling and can reduce the relative cost of this behaviour by selectively recruiting preferredconspecifics. Observational studies of the brown-throated conure on the island of Bonaire showed thatoverflying groups were much more likely to settle in the area when a foraging group called to the overfly-ing group. However, foraging groups did not call to every overflying group, and food abundance alone didnot determine whether foraging groups would call. Playback experiments indicated that conures canrespond preferentially to social partners. Observational and experimental data suggest that brown-throatedconures may use loud contact calls selectively to recruit conspecifics to currently available foraging sites.! 2008 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.Keywords: Aratinga pertinax; brown-throated conure; contact call; fissionefusion; food calling; individual recognition;PsittaciformesForaging in groups can decrease the risk of predation orenhance food finding, but may reduce individual intakethrough either competition or direct stealing (Pulliam &Caraco 1984; Valone 1996; Bradbury & Vehrencamp1998; DiBitetti & Janson 2001). Foragers in flexible socie-ties, such as fissionefusion groups, can maximize benefitsand minimize costs through selective associations withpreferred social partners. Foragers may choose to avoid for-aging with dominant or aggressive individuals (Chapman& Lefebvre 1990), or preferentially forage with social groupmembers who can aid in resource defence (Wilkinson &Boughman 1998). Foragers may also actively recruit othersto forage with them. In doing so, they may offset the costsof sharing through benefits such as reduced predation riskthrough increased group size (Elgar 1986; Newman &Caraco 1989; Caine et al. 1995), increased opportunitiesto mate (Evans & Marler 1994), assistance with resource de-fence (Heinrich & Marzluff 1991; Wilkinson & Boughman1998), enhanced ability to find food (e.g. Brown et al. 1991)and a reduction in punishment for not sharing (Hauser1992). Recruiters may also benefit from the recruitmentof kin (Judd & Sherman 1996) or reciprocal partners, whohave the potential to recruit the caller at a future time.Reciprocal sharing requires advanced cognitive abilities tofactor in future discounting and thus is probably limitedto a small number of species that are able to maintainlong-term social memories (Stevens & Gilby 2004).The dynamic nature of fissionefusion societies poseschallenges for maintaining social bonds while foraging.Individuals need to locate mates and other preferred socialpartners amid shifting group associations. In long-livedspecies, individuals may meet for only brief periods butneed to remember previous contacts. To facilitate suchsocial accounting, many species rely on signals thatconvey individual-specific information. In species withlarge, overlapping home ranges, this information is oftencontained in long-distance contact calls (Bradbury &Vehrencamp 1998). Individuals may use the informationin these calls in deciding whether to forage with others.Most species of parrot (Psittaciformes) are nonterritorial,with dynamic fissionefusion societies in which groupCorrespondence: S. C. Buhrman-Deever, 11 Woodstock Lane, Pittsford,NY 14534, U.S.A. (email: [email protected]). E. A. Hobson is now atthe Department of Biology, New Mexico State University, Las Cruces,NM, U.S.A.17150003e 3472/08/$34.00/0 ! 2008 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.ANIMAL BEHAVIOUR, 2008, 76, 1715e1725doi:10.1016/j.anbehav.2008.08.007composition shifts frequently throughout the day (Brad-bury 2003). Parrots are predominantly seed predatorsand as such are unwelcome visitors to plants. Many plantshave responded-to parrots and other seed predators bymaking their fruit hard to spot or by adding toxic second-ary compounds to the fruit or seeds (Bradbury 2003).Other plants rely on unpredictable phenologies or activelyattract seed dispersers that can compete with the seedpredators. These coevolutionary adaptations make forag-ing a daily challenge for wild parrots (Bradbury 2003).Given these challenges, the sharing of public information(Valone 1996) and coarse-level local enhancement (Poysa1992) could be very valuable for parrots. However,although the green coloration and quiet foraging habitsof many parrot species conceal individuals from aerialpredators while foraging in foliage (Juniper & Parr 1998;Bradbury 2003), they also probably conceal foraginggroups from overflying conspecifics.Nearly all species of parrot have a loud contact call, usedto maintain contact between visually separated individ-uals (Forshaw 1989; Farabaugh & Dooling 1996; Bradbury2003). Given its function in generating and/or maintain-ing