Calling in the Face of Danger: Predation Risk and Acoustic Communication by Parent Birds and Their Offspring

Abstract Birds raise their young under constant risk of predation, which shapes how parents and young communicate acoustically. Nestling begging calls extract care from parents but expose them to eavesdropping by predators, which selects for cryptic signal design. However, for largely unknown reasons, nestlings often call even when parents are absent and thus unavailable for defense. Nestlings can give distress and defensive calls, but their efficacy is unknown. Parental alarm calls warn young of danger in some species, and young can show adaptive changes in response according to their age-related vulnerability to specific predators. Parents often signal their arrival at the nest with provisioning calls, which might reduce mistaken begging and increase the efficiency of feeding, and thereby minimize detection by predators. Acoustic interactions between offspring and parents can lead to young either remaining silent until prompted by a parent's provisioning call, or begging indiscriminately to subtle cues of arrival while remaining alert to parental alarm calls. Young can also assess danger independently of parents, which could in turn affect parental decisions about giving alarm calls. All these behaviors offer fertile ground for studying how animals trade off acoustic communication with the risk of eavesdropping.

[1]  Charles H. Brown,et al.  Comparative Mammalian Sound Localization , 2005 .

[2]  K. Teather An experimental study of competition for food between male and female nestlings of the red-winged blackbird , 1992, Behavioral Ecology and Sociobiology.

[3]  L. Zanette What do artificial nests tells us about nest predation , 2002 .

[4]  Olof O. Rydéan Selective resistance to approach: a precursor to fear responses to an alarm call in great tit nestlings Parus major. , 1982 .

[5]  J. R. Clemmons,et al.  Development of Early Vocalizations and the Chick-a-dee Call in the Black-capped Chickadee, Parus atricapillus , 2010 .

[6]  Matthew G. Johnson,et al.  Parent--offspring communication in the western sandpiper , 2008 .

[7]  C. Blaich,et al.  Alarm call responsivity of mallard ducklings: III. Acoustic features affecting behavioral inhibition. , 1986, Developmental psychobiology.

[8]  A. S. Griffin,et al.  Social learning about predators: a review and prospectus , 2004, Learning & behavior.

[9]  O. Rydén,et al.  Development of Parent‐Young Interaction in Asynchronously Hatched Broods of Altricial Birds , 2010 .

[10]  N. Davies,et al.  Learning fine-tunes a specific response of nestlings to the parental alarm calls of their own species , 2004, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[11]  R. D. Magrath,et al.  Nestling weight and juvenile survival in the Blackbird, Turdus merula , 1991 .

[12]  Jonathan Wright,et al.  Provisioning Vocalizations in Cooperative Bell Miners (Manorina Melanophrys): More than a Simple Stimulus for Nestling Begging , 2008 .

[13]  G. Nuechterlein,et al.  PARENT-YOUNG VOCAL COMMUNICATION IN EARED GREBES , 1993 .

[14]  T. Peake,et al.  Animal Communication Networks: Eavesdropping in communication networks , 2005 .

[15]  M. Ficken,et al.  COMPARATIVE ANALYSIS OF ACOUSTIC STRUCTURE OF PASSERINE AND WOODPECKER NESTLING CALLS , 1991 .

[16]  George L. Farnsworth,et al.  Factors Affecting Nesting Success of Wood Thrushes in Great Smoky Mountains National Park , 1999 .

[17]  J. Ekman,et al.  Predator-induced plasticity in nest visitation rates in the Siberian jay (Perisoreus infaustus) , 2005 .

[18]  O. Larsen,et al.  Degradation of song in a species using nesting holes: the Pied Flycatcher Ficedula hypoleuca. , 2004, Anais da Academia Brasileira de Ciencias.

[19]  Andrew G. Horn,et al.  Efficacy and the Design of Begging Signals , 2002 .

[20]  N. Davies,et al.  Signals of need in parent–offspring communication and their exploitation by the common cuckoo , 1999, Nature.

[21]  R. Kilner The evolution of egg colour and patterning in birds , 2006, Biological reviews of the Cambridge Philosophical Society.

[22]  A. Horn,et al.  Begging to differ: scrubwren nestlings beg to alarm calls and vocalize when parents are absent , 2003, Animal Behaviour.

[23]  Lauryn Benedict OFFSPRING DISCRIMINATION WITHOUT RECOGNITION: CALIFORNIA TOWHEE RESPONSES TO CHICK DISTRESS CALLS , 2007 .

[24]  N. Raihani,et al.  Variable fledging age according to group size: trade-offs in a cooperatively breeding bird , 2007, Biology Letters.

[25]  IBERIAN AZURE-WINGED MAGPIE CYANOPICA (CYANA) COOKI NESTLINGS BEGGING CALLS: CALL CHARACTERIZATION AND HUNGER SIGNALLING , 2008 .

[26]  G. Gottlieb Development of species identification in ducklings: V. Perceptual differentiation in the embryo. , 1979 .

[27]  M. Leonard,et al.  Parental Calls and Nestling Behavior in Tree Swallows , 1997 .

[28]  The significance of antecedent auditory experiences on later reactions to the "seeet" alarm-call in great tit nestlings Parus major. , 2010, Zeitschrift fur Tierpsychologie.

[29]  J. R. Clemmons Vocalizations and other stimuli that elicit gaping in nestling black-capped chickadees (Parus atricapillus) , 1995 .

[30]  C. Whelan,et al.  QUANTIFYING MALE WOOD THRUSH NEST-ATTENDANCE AND ITS RELATIONSHIP TO NEST SUCCESS , 2005 .

[31]  M. Chaiken INDIVIDUAL RECOGNITION OF NESTLING DISTRESS SCREAMS BY EUROPEAN STARLINGS (STURNUS VULGARIS) , 1992 .

[32]  The evolution of fledging age in songbirds , 2005, Journal of evolutionary biology.

[33]  G. J. Fernández,et al.  Alarm calls of the Southern House Wren Troglodytes musculus: variation with nesting stage and predator model , 2009, Journal of Ornithology.

[34]  J. Roper,et al.  A test of the Skutch hypothesis: does activity at nests increase nest predation risk? , 1997 .

[35]  E. Korneeva,et al.  Development of the auditory sensitivity and formation of the acoustically guided defensive behavior in nestlings of the pied flycatcher Ficedula hypoleuca , 2006, Journal of Evolutionary Biochemistry and Physiology.

[36]  M. D. Plessis,et al.  Nest predation of grassland bird species increases with parental activity at the nest , 2005 .

[37]  R. L. Knight,et al.  Nest-defense behavior in the red-winged blackbird , 1988 .

[38]  A. Horn,et al.  Age‐Related Changes in Signalling of Need by Nestling Tree Swallows (Tachycineta bicolor) , 2006 .

[39]  J. Emlen,et al.  THE DEVELOPTMENT OF VISUAL DISCRIMINATION PATTERNS IN THE CROUCHING REACTIONS OF NESTLING GRACKLES , 1961 .

[40]  R. Major,et al.  The contribution of artificial nest experiments to understanding avian reproductive success: a review of methods and conclusions , 2008 .

[41]  Jonathan Wright,et al.  The evolution of begging : competition, cooperation, and communication , 2002 .

[42]  S. Nowicki,et al.  The Evolution of Animal Communication: Reliability and Deception in Signaling Systems: Reliability and Deception in Signaling Systems , 2005 .

[43]  T. E. Martin,et al.  Nest predation increases with parental activity: separating nest site and parental activity effects , 2000, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[44]  Eberhard Curio,et al.  The adaptive significance of avian mobbing. III. Cultural transmission of enemy recognition in blackbirds: Cross-species tutoring and properties of learning , 1980, Animal Behaviour.

[45]  K. Weidinger Interactive effects of concealment, parental behaviour and predators on the survival of open passerine nests , 2002 .

[46]  S. Wilson,et al.  Does cowbird parasitism increase predation risk to American redstart nests , 2009 .

[47]  S. N. Khayutin Sensory Factors in the Behavioral Ontogeny of Altricial Birds , 1985 .

[48]  T. Redondo,et al.  Locatability of begging calls in nestling altricial birds , 1988, Animal Behaviour.

[49]  David B. Miller Maternal vocal control of behavioral inhibition in mallard ducklings (Anas platyrhynchos). , 1980 .

[50]  N. Raihani,et al.  Adult vocalizations during provisioning: offspring response and postfledging benefits in wild pied babblers , 2007, Animal Behaviour.

[51]  N. Davies,et al.  A host-race of the cuckoo Cuculus canorus with nestlings attuned to the parental alarm calls of the host species , 2006, Proceedings of the Royal Society B: Biological Sciences.

[52]  R. D. Magrath,et al.  Long-term brood division and exclusive parental care in a cooperatively breeding passerine , 2003, Animal Behaviour.

[53]  Konrad Halupka,et al.  Vocal begging by nestlings and vulnerability to nest predation in Meadow Pipits Anthus pratensis; to what extent do predation costs of begging exist? , 2008 .

[54]  C. Blaich,et al.  Alarm call responsivity of mallard ducklings: V. Age-related changes in repetition rate specificity and behavioral inhibition. , 1987, Developmental psychobiology.

[55]  U. Ernst,et al.  Cultural Transmission of Enemy Recognition: One Function of Mobbing , 1978, Science.

[56]  K. Zuberbühler,et al.  Interspecies semantic communication in two forest primates , 2000, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[57]  W. Thompson Vocalizations of the Lazuli Bunting , 1976 .

[58]  R. Montgomerie,et al.  Nestling American robins compete with siblings by begging , 1991, Behavioral Ecology and Sociobiology.

[59]  D. Dearborn,et al.  BROWN-HEADED COWBIRD NESTLING VOCALIZATIONS AND RISK OF NEST PREDATION , 1999 .

[60]  Dirk Platzen Parent-nestling vocal interactions in the white-browed scrubwren , 2004 .

[61]  T. Redondo Early stages of vocal ontogeny in the magpie (Pica pica) , 1991, Journal für Ornithologie.

[62]  I. Mclean,et al.  Age, experience, and enemy recognition by wild song sparrows , 1984, Behavioral Ecology and Sociobiology.

[63]  M. Jurisevic Structural Change of Begging Vocalisations and Vocal Repertoires in Two Hand-raised Australian Passerines, the Little Raven Corvus mellori and White-winged Chough Corcorax melanorhamphos , 1999 .

[64]  R. Márquez,et al.  Brood size and nestling vocal begging behaviour in the Spanish Sparrow Passer hispaniolensis , 2006 .

[65]  R. L. Knight,et al.  Nest defence in the American goldfinch , 1986, Animal Behaviour.

[66]  B. Naef-Daenzer,et al.  Differential post-fledging survival of great and coal tits in relation to their condition and fledging date , 2001 .

[67]  F. Kuhlmann Some preliminary observations on the development of instincts and habits in young birds. , 1909 .

[68]  Jonathan Wright,et al.  Begging in Nestling Birds , 2001 .

[69]  H. Godfray,et al.  Evolutionary theory of parent–offspring conflict , 1995, Nature.

[70]  J. Carranza,et al.  Offspring reproductive value and nest defense in the magpie (Pica pica) , 1989, Behavioral Ecology and Sociobiology.

[71]  T. Clutton‐Brock,et al.  Calling in the gap: competition or cooperation in littermates' begging behaviour? , 2009, Proceedings of the Royal Society B: Biological Sciences.

[72]  N. Davies,et al.  Differences in the nestling begging calls of hosts and host-races of the common cuckoo, Cuculus canorus , 2003, Animal Behaviour.

[73]  Juha T. Tanttu,et al.  AUTOMATIC FEATURE EXTRACTION AND CLASSIFICATION OF CROSSBILL (LOXIA SPP.) FLIGHT CALLS , 2006 .

[74]  Dirk Platzen,et al.  Adaptive differences in response to two types of parental alarm call in altricial nestlings , 2005, Proceedings of the Royal Society B: Biological Sciences.

[75]  R. Fay,et al.  Introduction to Sound Source Localization , 2005 .

[76]  David G. Haskell Do bright colors at nests incur a cost due to predation? , 1996, Evolutionary Ecology.

[77]  M. C. Baker,et al.  DEVELOPMENT OF VOCALISATIONS IN NESTLING AND FLEDGLING HOUSE WRENS IN NATURAL POPULATIONS , 2006 .

[78]  G. Klump,et al.  Acoustic Behaviour of Birds and Mammals in the Predator Context; I. Factors Affecting the Structure of Alarm Signals. II. The Functional Significance and Evolution of Alarm Signals , 2010 .

[79]  T. Redondo Avian Nest Defence: Theoretical Models and Evidence , 1989 .

[80]  J. McDaniel,et al.  Is it safe? Red-eyed treefrog embryos assessing predation risk use two features of rain vibrations to avoid false alarms , 2010, Animal Behaviour.

[81]  S. Gill,et al.  Tests of two functions of alarm calls given by yellow warblers during nest defence , 2003 .

[82]  T. O. Crist,et al.  Suppression of escape behaviour during mating in the cricket Acheta domesticus , 2006, Animal Behaviour.

[83]  M. Pagel,et al.  The comparative method in evolutionary biology , 1991 .

[84]  A. Skutch,et al.  DO TROPICAL BIRDS REAR AS MANY YOUNG AS THEY CAN NOURISH , 2008 .

[85]  G. Moreno-Rueda A trade-off between predation risk and sibling competition in the begging behavior of Coal and Great Tits , 2005 .

[86]  M. Ryan The Tungara Frog: A Study in Sexual Selection and Communication , 1986 .

[87]  M. Leonard,et al.  Begging and the risk of predation in nestling birds , 1997 .

[88]  Ulrike Langemann,et al.  Effects of signal features and environmental noise on signal detection in the great tit, Parus major , 2009, Animal Behaviour.

[89]  S. Gill,et al.  Nest Defence By Yellow Warblers: Recognition of a Brood Parasite and an Avian Nest Predator , 1996 .

[90]  J. Ekman,et al.  Nepotistic alarm calling in the Siberian jay, Perisoreus infaustus , 2004, Animal Behaviour.

[91]  P. Procházka,et al.  Hopeless solicitation? Host-absent vocalization in the common cuckoo has no effect on feeding rate of reed warblers , 2007, Journal of Ethology.

[92]  M. Impekoven Prenatal experience of parental calls and pecking in the laughing gull (Larus atricilla L.) , 1971 .

[93]  Ulrike Langemann,et al.  Animal Communication Networks: Perception and acoustic communication networks , 2005 .

[94]  S. Forbes,et al.  Muting individual nestlings reduces parental foraging for the brood , 2002, Animal Behaviour.

[95]  S. Forbes,et al.  Why brown-headed cowbirds do not influence red-winged blackbird parent behaviour , 2003, Animal Behaviour.

[96]  R. Wilkinson VOCAL BEHAVIOUR AND CALL DEVELOPMENT IN THE BULLFINCH (PYRRHULA PYRRHULA) , 1990 .

[97]  N. Aebischer,et al.  The Growth and Development of Birds , 1984 .

[98]  I. R. Hartley,et al.  Stimuli for nestling begging in blue tits Cyanistes caeruleus: hungry nestlings are less discriminating , 2007 .

[99]  G. Moreno-Rueda Is there empirical evidence for the cost of begging? , 2007, Journal of Ethology.

[100]  T. E. Martin Nest Predation and Nest SitesNew perspectives on old patterns , 1993 .

[101]  A. Horn,et al.  Begging in the absence of parents by nestling tree swallows , 2001 .

[102]  J. Marzluff Behavior at a Pinyon Jay nest in response to predation , 1985 .

[103]  T. E. Martin,et al.  Habitat Selection Responses of Parents to Offspring Predation Risk: An Experimental Test , 2006, The American Naturalist.

[104]  N. Davies,et al.  Social Transmission of a Host Defense Against Cuckoo Parasitism , 2009, Science.

[105]  A. Roulin,et al.  Vocal sib–sib interactions: how siblings adjust signalling level to each other , 2009, Animal Behaviour.

[106]  Jonathan Wright,et al.  Provisioning calls of the cooperatively breeding bell miner Manorina melanophrys encode sufficient information for individual discrimination , 2007 .

[107]  K. Zuberbühler Referential labelling in Diana monkeys , 2000, Animal Behaviour.

[108]  Otto J. Sieber Individual recognition of parental calls by bank swallow chicks (Riparia riparia) , 1985, Animal Behaviour.

[109]  Carl T. Bergstrom,et al.  Signaling among relatives. III. Talk is cheap. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[110]  Andrew N. Radford,et al.  The development of alarm call behaviour in mammals and birds , 2009, Animal Behaviour.

[111]  P. K. McGregor,et al.  Individual and sex differences in the provisioning calls of European bee-eaters , 1995, Animal Behaviour.

[112]  T. E. Martin,et al.  Testing ecological and behavioral correlates of nest predation , 2007 .

[113]  A. Skutch Parent birds and their young , 1976 .

[114]  R. Márquez,et al.  Nestling Begging Call Structure and Bout Variation Honestly Signal Need but Not Condition in Spanish Sparrows , 2009 .

[115]  M. Hauber,et al.  Species specificity of grey warbler begging solicitation and alarm calls revealed by nestling responses to playbacks , 2010, Animal Behaviour.

[116]  D. Hussell Supply and Demand in Tree Swallow Broods: A Model of Parent-Offspring Food-Provisioning Interactions in Birds , 1988, The American Naturalist.

[117]  M. Lachmann,et al.  Role of begging and sibling competition in foraging strategies of nestlings , 2001, Animal Behaviour.

[118]  P. Quillfeldt Begging in the absence of sibling competition in Wilson’s storm-petrels, Oceanites oceanicus , 2002, Animal Behaviour.

[119]  N. Royle,et al.  Begging for control: when are offspring solicitation behaviours honest? , 2002 .

[120]  C. Hinde,et al.  Chapter 6 Information Warfare and Parent–Offspring Conflict , 2008 .

[121]  Michael Griesser,et al.  Referential Calls Signal Predator Behavior in a Group-Living Bird Species , 2008, Current Biology.

[122]  N. Raihani,et al.  Synchronous provisioning increases brood survival in cooperatively breeding pied babblers. , 2010, The Journal of animal ecology.

[123]  David G. Haskell Begging Behaviour and Nest Predation , 2002 .

[124]  Otars Opermanis Appearance and vulnerability of artificial duck nests to avian predators , 2004 .

[125]  K. Yasukawa,et al.  The costs and benefits of a vocal signal: the nest-associated ‘Chit’ of the female red-winged blackbird, Agelaius phoeniceus , 1989, Animal Behaviour.

[126]  N. Metcalfe,et al.  A hidden cost of reproduction: the trade-off between clutch size and escape take-off speed in female zebra finches , 2001 .

[127]  Andrew Horn,et al.  Provisioning rules in tree swallows , 1996, Behavioral Ecology and Sociobiology.

[128]  J. Ekman,et al.  Nepotistic mobbing behaviour in the Siberian jay, Perisoreus infaustus , 2005, Animal Behaviour.

[129]  Rick A. Relyea,et al.  HOW PREY RESPOND TO COMBINED PREDATORS: A REVIEW AND AN EMPIRICAL TEST , 2003 .

[130]  T. E. Martin,et al.  Avian Life History Evolution in Relation to Nest Sites, Nest Predation, and Food , 1995 .

[131]  R. Dooling,et al.  Detection and discrimination of natural calls in masking noise by birds: estimating the active space of a signal , 2003, Animal Behaviour.

[132]  Jonathan Wright,et al.  Falling on deaf ears: the adaptive significance of begging in the absence of a parent , 2001, Behavioral Ecology and Sociobiology.

[133]  T. E. Martin,et al.  Predation on Dependent Offspring , 2009, Annals of the New York Academy of Sciences.

[134]  U. Ernst,et al.  The adaptive significance of avian mobbing: II. Cultural transmission of enemy recognition in blackbirds: Effectiveness and some constraints. , 2010 .

[135]  C. Tarwater,et al.  Parental response to elevated begging in a high predation, tropical environment , 2009, Animal Behaviour.

[136]  A. Horn,et al.  Acoustic signalling of hunger and thermal state by nestling tree swallows , 2001, Animal Behaviour.

[137]  D. Winkler,et al.  Begging in the absence of parents: a "quick on the trigger" strategy to minimize costly misses , 2007 .

[138]  Donald E. Kroodsma,et al.  Pseudoreplication in playback experiments, revisited a decade later , 2001, Animal Behaviour.

[139]  C. Ghalambor,et al.  Comparative manipulation of predation risk in incubating birds reveals variability in the plasticity of responses , 2002 .

[140]  M. Manser,et al.  Begging Signals in a Mobile Feeding System: The Evolution of Different Call Types , 2007, The American Naturalist.

[141]  R. D. Magrath,et al.  Parental alarm calls suppress nestling vocalization , 2004, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[142]  M. East ALARM CALLING AND PARENTAL INVESTMENT IN THE ROBIN ERITHACUS RUBECULA , 2008 .

[143]  O. Rydén Heart rate response in great tit nestlings (Parus major) to an alarm call. , 1980, Journal of comparative and physiological psychology.

[144]  Sajithya Perera The Impact of Ambient Noise on Eastern Bluebird (Sialia sialis) Nestling Begging , 2008 .

[145]  P. Stoddard,et al.  RECOGNITION OF PARENTS' VOICES BY YOUNG CLIFF SWALLOWS , 1985 .

[146]  Roulin Screaming as a strategy to reduce the predation risk incurred by begging , 2001 .

[147]  Gary L. Grabowski Vocalizations of the Rufous-Backed Thrush (Turdus rufopalliatus) in Guerrero, Mexico , 1979 .

[148]  E. Nemeth,et al.  Reed bunting (Emberiza schoeniclus) males sing an 'all-clear' signal to their incubating females , 2007 .

[149]  J. R. Clemmons Development of a selective response to an adult vocalization in nestling black-capped chickadees , 1995 .

[150]  D. H. Owings,et al.  Rattlesnake Rattles and Burrowing Owl Hisses: A Case of Acoustic Batesian Mimicry , 2010 .

[151]  T. Krama,et al.  Cost of mobbing call to breeding pied flycatcher, Ficedula hypoleuca , 2005 .

[152]  P. Crochet,et al.  Predator-induced plasticity in early life history and morphology in two anuran amphibians , 2002, Oecologia.

[153]  T. E. Martin,et al.  Parent birds assess nest predation risk and adjust their reproductive strategies. , 2006, Ecology letters.

[154]  A. Harper,et al.  The Evolution of Begging: Sibling Competition and Parent-Offspring Conflict , 1986, The American Naturalist.

[155]  C. Darwin The Expression of Emotion in Man and Animals , 2020 .

[156]  M. D. Beecher,et al.  Parent-offspring recognition in bank swallows (Riparia riparia): I. Natural history , 1981, Animal Behaviour.

[157]  A. Horn,et al.  Begging calls and parental feeding decisions in tree swallows (Tachycineta bicolor) , 2001, Behavioral Ecology and Sociobiology.

[158]  Klaus Zuberbühler,et al.  Causal knowledge of predators' behaviour in wild Diana monkeys , 2000, Animal Behaviour.

[159]  K. Apel,et al.  The hiss-display of nesting Black-capped Chickadees in captivity , 1986 .

[160]  R. Dooling,et al.  Vocal development in budgerigars (Melopsittacus undulatus): contact calls. , 1997, Journal of comparative psychology.

[161]  Benjamin J. Pitcher,et al.  How to be fed but not eaten: nestling responses to parental food calls and the sound of a predator's footsteps , 2007, Animal Behaviour.

[162]  R. Ydenberg,et al.  Provisioning response to manipulation of apparent predation danger by parental Pied Flycatchers , 2002 .

[163]  Robert M. Seyfarth,et al.  Suricate alarm calls signal predator class and urgency , 2002, Trends in Cognitive Sciences.

[164]  D. Borror red-winged blackbird , 2008 .

[165]  R. Kilner The Evolution of Complex Begging Displays , 2002 .

[166]  H. Greeney,et al.  The influence of parental behavior on vulnerability to nest predation in tropical thrushes of an Andean cloud forest , 2009 .

[167]  N. Royle,et al.  Begging scrambles with unequal chicks: interactions between need and competitive ability , 2002 .

[168]  Antipredation role of clumped nesting by marsh-nesting red-winged blackbirds , 2004, Behavioral Ecology and Sociobiology.

[169]  H. Godfray,et al.  Signalling of need by offspring to their parents , 1991, Nature.

[170]  David G. Haskell,et al.  The effect of predation on begging-call evolution in nestling wood warblers , 1999, Animal Behaviour.

[171]  F. Grieco Short-term regulation of food-provisioning rate and effect on prey size in blue tits, Parus caeruleus , 2001, Animal Behaviour.

[172]  K. Zuberbühler Chapter 8 Survivor Signals , 2009 .

[173]  A. Roulin,et al.  Barn owl (Tyto alba) siblings vocally negotiate resources , 2000, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[174]  T. Pärt,et al.  Do artificial nests reveal relative nest predation risk for real nests , 2002 .

[175]  Robert D. Magrath,et al.  Communicating about danger: urgency alarm calling in a bird , 2005, Animal Behaviour.

[176]  A. Horn,et al.  False alarms and begging in nestling birds , 2005, Animal Behaviour.

[177]  C. Wiklund,et al.  Parental defence of offspring: A model and an example , 1980, Animal Behaviour.

[178]  David R. Wilson,et al.  Nestling begging increases predation risk, regardless of spectral characteristics or avian mobbing , 2009 .

[179]  J. Burger,et al.  Antipredator Behaviour in Nesting Zenaida Doves (Zenaida Aurita): Parental Investment or Offspring Vulnerability , 1989 .

[180]  Paul R. Martin,et al.  Nest predation and the evolution of nestling begging calls , 1999, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[181]  K. Yasukawa,et al.  THE “PREDATOR EARLY WARNING SYSTEM” OF RED-WINGED BLACKBIRDS , 2001 .

[182]  C. Ghalambor,et al.  Adaptive phenotypic plasticity in an island songbird exposed to a novel predation risk , 2008 .

[183]  Erick Greene,et al.  Allometry of Alarm Calls: Black-Capped Chickadees Encode Information About Predator Size , 2005, Science.

[184]  J. Walters,et al.  Causes of reduced clutch size in a tidal marsh endemic , 2008, Oecologia.

[185]  Marta B. Manser,et al.  The Evolution of Urgency‐Based and Functionally Referential Alarm Calls in Ground‐Dwelling Species , 2009, The American Naturalist.

[186]  P. Greig-Smith Parental investment in nest defence by stonechats (Saxicola torquata) , 1980, Animal Behaviour.

[187]  Andrew Sih,et al.  Delayed Hatching of Salamander Eggs in Response to Enhanced Larval Predation Risk , 1993, The American Naturalist.

[188]  P. Marler,et al.  Monkey responses to three different alarm calls: evidence of predator classification and semantic communication. , 1980, Science.

[189]  R. Sacchi,et al.  Features of begging calls reveal general condition and need of food of barn swallow (Hirundo rustica) nestlings , 2002 .

[190]  G. Ruxton Non-visual crypsis: a review of the empirical evidence for camouflage to senses other than vision , 2009, Philosophical Transactions of the Royal Society B: Biological Sciences.

[191]  K. Warkentin How do embryos assess risk? Vibrational cues in predator-induced hatching of red-eyed treefrogs , 2005, Animal Behaviour.

[192]  T. Haff,et al.  Vulnerable but not helpless: nestlings are fine-tuned to cues of approaching danger , 2010, Animal Behaviour.

[193]  T. E. Martin,et al.  Parental care and clutch sizes in North and South American birds. , 2000, Science.

[194]  D. Dearborn,et al.  Begging behavior and food acquisition by brown-headed cowbird nestlings , 1998, Behavioral Ecology and Sociobiology.

[195]  S. Sargent Nesting biology of the yellow-throated euphonia: large clutch size in a neotropical frugivore , 1993 .

[196]  D. Gil,et al.  Parent-absent begging: evidence for sibling honesty and cooperation in the spotless starling (Sturnus unicolor) , 2007 .

[197]  C. Ghalambor,et al.  Fecundity-Survival Trade-Offs and Parental Risk-Taking in Birds , 2001, Science.

[198]  H. Hoi,et al.  Alarm calls and chick reactions in the moustached warbler, Acrocephalus melanopogon , 1996, Animal Behaviour.

[199]  D. Chivers,et al.  Avoidance Response of Juvenile Pacific Treefrogs to Chemical Cues of Introduced Predatory Bullfrogs , 2001, Journal of Chemical Ecology.

[200]  Christopher M. Perrins,et al.  Population fluctuations and clutch size in the Great tit , 1965 .

[201]  T. E. Martin,et al.  Introduced Mammalian Predators Induce Behavioural Changes in Parental Care in an Endemic New Zealand Bird , 2008, PloS one.

[202]  S. Gaioni,et al.  Conspecific calls evoke characteristic cardiac responses in mallard ducklings , 1990, Animal Behaviour.

[203]  A. Grafen Biological signals as handicaps. , 1990, Journal of theoretical biology.

[204]  J. Lind,et al.  An experimental study of predator recognition in great tit fledglings , 2002 .

[205]  A. Horn,et al.  Dynamics of calling by tree swallow (Tachycineta bicolor) nestmates , 2001, Behavioral Ecology and Sociobiology.

[206]  A. Roulin On the cost of begging vocalization: implications of vigilance , 2001 .

[207]  P. McGregor,et al.  Female great tits can identify mates by song , 1996, Animal Behaviour.

[208]  K. Weidinger How well do predation rates on artificial nests estimate predation on natural passerine nests , 2001 .

[209]  M. D. Beecher,et al.  Parent-offspring recognition in bank swallows (Riparia riparia): II. Development and acoustic basis , 1981, Animal Behaviour.

[210]  A. Thornton,et al.  Teaching in Wild Meerkats , 2006, Science.

[211]  H. Godfray Signaling of Need between Parents and Young: Parent-Offspring Conflict and Sibling Rivalry , 1995, The American Naturalist.

[212]  ENVIRONMENTAL INFLUENCES ON THE EVOLUTION OF GROWTH AND DEVELOPMENTAL RATES IN PASSERINES , 2002, Evolution; international journal of organic evolution.

[213]  C. Hinde,et al.  Negotiations within the family over the supply of parental care , 2007, Proceedings of the Royal Society B: Biological Sciences.

[214]  David G. Haskell Experimental evidence that nestling begging behaviour incurs a cost due to nest predation , 1994, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[215]  A. Radford,et al.  The value of constant surveillance in a risky environment , 2009, Proceedings of the Royal Society B: Biological Sciences.

[216]  Jack W. Bradbury,et al.  Principles of Animal Communication , 1998 .

[217]  N. Davies,et al.  Cuckoos, Cowbirds and Other Cheats , 2000 .

[218]  Marc Naguib,et al.  Estimating the distance to a source of sound: mechanisms and adaptations for long-range communication , 2001, Animal Behaviour.

[219]  D. Mennill,et al.  Nest cavity orientation in black-capped chickadees Poecile atricapillus: do the acoustic properties of cavities influence sound reception in the nest and extra-pair matings? , 2004 .

[220]  M. Impekoven Responses of Laughing Gull Chicks (Larus Atricilla) To Parental Attraction- and Alarm-Calls, and Effects of Prenatal Auditory Experience On the Responsiveness To Such Calls , 1976 .

[221]  W. Wickler Coordination of Vigilance in Bird Groups. The “Watchman's Song” Hypothesis , 2010 .

[222]  F. Thompson,et al.  Differences in Predators of Artificial and Real Songbird Nests: Evidence of Bias in Artificial Nest Studies , 2004 .

[223]  John Maynard Smith Honest signalling: the Philip Sidney game , 1991, Animal Behaviour.

[224]  A. Zahavi Reliability in communication systems and the evolution of altruism , 1977 .

[225]  Junko Kondo,et al.  From nestling calls to fledgling silence: adaptive timing of change in response to aerial alarm calls , 2006, Proceedings of the Royal Society B: Biological Sciences.

[226]  O. Rydén Differential Responsiveness of Great Tit Nestlings, Parus major, to Natural Auditory Stimuli , 2010 .

[227]  R. Ricklefs An analysis of nesting mortality in birds , 1969 .

[228]  Ken A. Elliott,et al.  Patterns of Nest Predation on Artificial and Natural Nests in Forests , 2004 .

[229]  D. Kroodsma Using appropriate experimental designs for intended hypotheses in ‘song’ playbacks, with examples for testing effects of song repertoire sizes , 1990, Animal Behaviour.

[230]  J. Rivers Parent-absent begging in the Brown-headed Cowbird (Molothrus ater): the role of short-term need and nestmate size , 2009, Behavioral Ecology and Sociobiology.

[231]  S. L. Lima Predators and the breeding bird: behavioral and reproductive flexibility under the risk of predation , 2009, Biological reviews of the Cambridge Philosophical Society.

[232]  N. Davies,et al.  Nestling responses to adult food and alarm calls: 1. Species-specific responses in two cowbird hosts , 2005, Animal Behaviour.

[233]  M. Zuk,et al.  Exploitation of Sexual Signals by Predators and Parasitoids , 1998, The Quarterly Review of Biology.

[234]  R. Montgomerie,et al.  Risks and Rewards of Nest Defence by Parent Birds , 1988, The Quarterly Review of Biology.

[235]  Erlend B. Nilsen Antipredator Defences in Birds and Mammals , 2006 .

[236]  T. Grim Are Blackcaps (Sylvia atricapilla) defending their nests also calling for help from their neighbours? , 2008, Journal of Ornithology.

[237]  N. Raihani,et al.  Experimental evidence for teaching in wild pied babblers , 2008, Animal Behaviour.

[238]  I. Lovette,et al.  WHAT IS A WOOD-WARBLER? MOLECULAR CHARACTERIZATION OF A MONOPHYLETIC PARULIDAE , 2002 .

[239]  G. S. Bakken,et al.  Begging Response in Nestling Red-winged Blackbirds (Agelaius phoeniceus): Effect of Body Temperature , 1990, Physiological Zoology.

[240]  N. Davies,et al.  Nestling responses to adult food and alarm calls: 2. Cowbirds and red-winged blackbirds reared by eastern phoebe hosts , 2005, Animal Behaviour.

[241]  S. Martindale Nest defense and central place foraging: A model and experiment , 1982, Behavioral Ecology and Sociobiology.

[242]  P. Batáry,et al.  Dummy birds in artificial nest studies: an experiment with Red-backed Shrike Lanius collurio , 2008 .

[243]  M. Enquist,et al.  Instability of signaling resolution models of parent-offspring conflict. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[244]  R. Ydenberg,et al.  Begging and provisioning in broods of asynchronously-hatched yellow-headed blackbird nestlings , 1995, Behavioral Ecology and Sociobiology.

[245]  T. Redondo,et al.  The increase in risk of predation with begging activity in broods of Magpies Pica pica , 2008 .