Scholars@Duke
Stephen Nowicki

Stephen Nowicki

Professor of Biology
Biology
snowicki@duke.edu
Duke Box 90338, Durham, NC 27708
137 Biological Sciences Building, 130 Science Drive, Durham, NC 27708

Selected Publications

Backgrounds and the evolution of visual signals.

Journal Article Trends in ecology & evolution · February 2024 Color signals which mediate behavioral interactions across taxa and contexts are often thought of as color 'patches' - parts of an animal that appear colorful compared to other parts of that animal. Color patches, however, cannot be considered in isolation ... Full text Cite

Human-wild bird cooperation.

Journal Article Science (New York, N.Y.) · December 2023 Honeyguides learn distinct signals made by honey hunters from different cultures. ... Full text Cite

Syntactic rules predict song type matching in a songbird

Journal Article Behavioral Ecology and Sociobiology · January 1, 2023 Abstract: Song type matching has been hypothesized to be a graded signal of aggression; however, it is often the case that variation in matching behavior is unrelated to variation in aggressiveness. An alternative view is that whether an individual matches ... Full text Open Access Cite

Are song sequencing rules learned by song sparrows?

Journal Article Animal Behaviour · October 1, 2022 Although the effects of learning on song structure have been extensively studied in songbirds, little attention has been given to the learning of syntax at the level of song sequences. Here we investigate song syntax learning in two cohorts of hand-reared ... Full text Open Access Cite

Influence of visual background on discrimination of signal-relevant colours in zebra finches (Taeniopygia guttata).

Journal Article Proceedings. Biological sciences · June 2022 Colour signals of many animals are surrounded by a high-contrast achromatic background, but little is known about the possible function of this arrangement. For both humans and non-human animals, the background colour surrounding a colour stimulus affects ... Full text Open Access Cite

Testosterone, signal coloration, and signal color perception in male zebra finch contests.

Journal Article Ethology : formerly Zeitschrift fur Tierpsychologie · February 2022 Many animals use assessment signals to resolve contests over limited resources while minimizing the costs of those contests. The carotenoid-based orange to red bills of male zebra finches (Taeniopygia guttata) are thought to function as assessment s ... Full text Open Access Cite

Animal communication

Chapter · January 10, 2022 An updated view of animal behavior studies, featuring global experts The Behavior of Animals, Second Edition provides a broad overview of the current state of animal behavior studies. ... Cite

Maturational changes in song sparrow song

Journal Article Journal of Avian Biology · January 1, 2022 Age-related changes in the production of sexually selected assessment signals have been identified across a diverse range of taxa, and in some cases, these changes have been shown to affect receiver response to those signals. One important type of change o ... Full text Open Access Cite

Long-distance dependencies in birdsong syntax.

Journal Article Proceedings. Biological sciences · January 2022 Songbird syntax is generally thought to be simple, in particular lacking long-distance dependencies in which one element affects choice of another occurring considerably later in the sequence. Here, we test for long-distance dependencies in the sequences o ... Full text Open Access Cite

Variation in vocal production learning across songbirds

Journal Article Philosophical Transactions of the Royal Society B: Biological Sciences · October 25, 2021 Open Access Cite

Comparison of Categorical Color Perception in Two Estrildid Finches.

Journal Article The American naturalist · February 2021 Featured Publication AbstractSensory systems are predicted to be adapted to the perception of important stimuli, such as signals used in communication. Prior work has shown that female zebra finches perceive the carotenoid-based orange-red coloration of male beaks-a mate choic ... Full text Open Access Cite

Sounds of senescence: Male swamp sparrows respond less aggressively to the songs of older individuals

Journal Article Behavioral Ecology · January 1, 2021 Featured Publication Age-related changes in assessment signals occur in a diverse array of animals, including humans. Age-related decline in vocal quality in humans is known to affect perceived attractiveness by potential mates and voters, but whether such changes have functio ... Full text Open Access Cite

Female swamp sparrows do not show evidence of discriminating between the songs of peak-aged and senescent males

Journal Article Ethology · January 1, 2021 Featured Publication Sexual selection theory predicts that females face contrasting selection pressures when choosing the age of their mate. On the one hand, older males have demonstrated their ability to survive and they may be more experienced than younger males. At the same ... Full text Open Access Cite

The many dimensions of categorical perception: A response to comments on Green et al

Journal Article Behavioral Ecology · January 1, 2021 Featured Publication Full text Open Access Cite

Differences in categorical color perception between two estrildid finches

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · 2021 Cite

Threshold assessment, categorical perception, and the evolution of reliable signaling.

Journal Article Evolution; international journal of organic evolution · December 2020 Animals often use assessment signals to communicate information about their quality to a variety of receivers, including potential mates, competitors, and predators. But what maintains reliable signaling and prevents signalers from signaling a better quali ... Full text Open Access Cite

Song performance improves with continued singing across the morning in a songbird

Journal Article Animal Behaviour · September 1, 2020 Vocal performance – an animal's ability to produce physically challenging vocalizations – can reflect a signaller's overall condition and can be a reliable signal of quality. It has been suggested recently that songbirds improve vocal performance through r ... Full text Open Access Cite

Variation in carotenoid-containing retinal oil droplets correlates with variation in perception of carotenoid coloration

Journal Article Behavioral Ecology and Sociobiology · July 1, 2020 Abstract: In the context of mate choice, males may vary continuously in their expression of assessment signals, typically reflecting information about variation in mate quality. Similarly, females may exhibit variation in mate preference, which could be du ... Full text Open Access Cite

Categorical perception in animal communication and decision-making

Journal Article Behavioral Ecology · January 1, 2020 The information an animal gathers from its environment, including that associated with signals, often varies continuously. Animals may respond to this continuous variation in a physical stimulus as lying in discrete categories rather than along a continuum ... Full text Open Access Cite

Von Uexküll Revisited: Addressing Human Biases in the Study of Animal Perception.

Journal Article Integrative and comparative biology · December 2019 More than 100 years ago, the biologist Jakob von Uexküll suggested that, because sensory systems are diverse, animals likely inhabit different sensory worlds (umwelten) than we do. Since von Uexküll, work across sensory modalities has confirmed that animal ... Full text Open Access Cite

Performance on tests of cognitive ability is not repeatable across years in a songbird

Journal Article Animal Behaviour · December 1, 2019 Studies of the cognitive abilities of animals aim to help us understand how they communicate, obtain resources, avoid danger and otherwise thrive in a given environment. But to what extent is cognitive ability a fixed trait in individuals? And can we answe ... Full text Cite

Animal Behavior: The Raised-by-Wolves Predicament.

Journal Article Current biology : CB · December 2019 Social learning poses a particular problem for brood parasites, which are raised by adults of another species. Brood-parasitic cowbirds use a password, a simple signal that aids the young in identifying appropriate models for learning of their species' beh ... Full text Cite

Full life course analysis of birdsong reveals maturation and senescence of highly repeatable song characteristics

Journal Article Behavioral Ecology · November 8, 2019 Signalers may benefit in some contexts from advertising their ages, for example in courting potential mates. Receivers in turn may benefit from assessing a signaler's age, even in cases where their doing so is against the signaler's interests. Indicators o ... Full text Cite

Constraints on song type matching in a songbird

Journal Article Behavioral Ecology and Sociobiology · August 1, 2019 Abstract: In an eastern population of song sparrows (Melospiza melodia), song type matching occurs at above chance levels but does not signal aggressiveness. One explanation for the apparent ineffectiveness of matching as a signal is that the occurrence of ... Full text Cite

Birdsong learning, avian cognition and the evolution of language

Journal Article Animal Behaviour · May 1, 2019 The most language-like aspect of the song of songbirds is its development: as with human speech, birdsong develops through vocal production learning, in which individuals modify the structure of their vocalizations in response to experience with the vocali ... Full text Cite

Categorical colour perception occurs in both signalling and non-signalling colour ranges in a songbird.

Journal Article Proceedings. Biological sciences · May 2019 Although perception begins when a stimulus is transduced by a sensory neuron, numerous perceptual mechanisms can modify sensory information as it is processed by an animal's nervous system. One such mechanism is categorical perception, in which (1) continu ... Full text Cite

Categorical Perception of a Carotenoid-based Assessment Signal

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · March 1, 2019 Link to item Cite

Song is not a reliable signal of general cognitive ability in a songbird

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · March 1, 2019 Link to item Cite

Intra-diel improvement in song performance: swamp sparrows 'warm up' in the morning

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · March 1, 2019 Link to item Cite

Signal reliability and intraspecific deception

Chapter · January 1, 2019 A signal is considered to be reliable if (1) some feature of the signal is consistently correlated with an attribute of the signaler or its environment and (2) receivers benefit from knowing about that attribute. Signaling systems that do not provide relia ... Full text Cite

Signal Reliability and Intraspecific Deception

Chapter · January 1, 2019 A signal is considered to be reliable if (1) some feature of the signal is consistently correlated with an attribute of the signaler or its environment and (2) receivers benefit from knowing about that attribute. Signaling systems that do not provide relia ... Full text Cite

Categorical perception of colour signals in a songbird.

Journal Article Nature · August 2018 In many contexts, animals assess each other using signals that vary continuously across individuals and, on average, reflect variation in the quality of the signaller1,2. It is often assumed that signal receivers perceive and respond continuousl ... Full text Cite

Data and scripts from: Categorical perception of colour signals in a songbird

Dataset · June 12, 2018 Categorical perception occurs when continuous variation in a stimulus (e.g., wavelength of color) is categorized by observers, with sharp changes in response occurring over a boundary and increased discrimination between stimuli that lie across a boundary ... Full text Cite

Cultural conformity generates extremely stable traditions in bird song.

Journal Article Nature communications · June 2018 Cultural traditions have been observed in a wide variety of animal species. It remains unclear, however, what is required for social learning to give rise to stable traditions: what level of precision and what learning strategies are required. We address t ... Full text Open Access Cite

Song type matching and vocal performance in territorial signalling by male swamp sparrows

Journal Article Animal Behaviour · May 1, 2018 In songbird species with repertoires of multiple songs, individuals in territorial interactions can engage in song type matching, in which one bird responds to another using the same song type. Song type matching is thought to be associated with aggressive ... Full text Cite

Early life conditions that impact song learning in male zebra finches also impact neural and behavioral responses to song in females.

Journal Article Developmental neurobiology · April 2018 Early life stressors can impair song in songbirds by negatively impacting brain development and subsequent learning. Even in species in which only males sing, early life stressors might also impact female behavior and its underlying neural mechanisms, but ... Full text Cite

Song is not a reliable signal of general cognitive ability in a songbird

Journal Article Animal Behaviour · March 1, 2018 Learned aspects of song affect female mating preferences in a number of species of songbirds, including swamp sparrows, Melospiza georgiana. One explanation for why female songbirds attend to such song features is that these song attributes convey informat ... Full text Cite

A test of the eavesdropping avoidance hypothesis as an explanation for the structure of low-amplitude aggressive signals in the song sparrow

Journal Article Behavioral Ecology and Sociobiology · March 1, 2018 Abstract: Low-amplitude signals function in private exchanges of information between signalers and nearby receivers. The eavesdropping avoidance hypothesis proposes that selection favors quiet threat signals in order to avoid the costs of eavesdroppers. If ... Full text Cite

Song learning and cognitive ability are not consistently related in a songbird.

Journal Article Animal cognition · March 2017 Learned aspects of song have been hypothesized to signal cognitive ability in songbirds. We tested this hypothesis in hand-reared song sparrows (Melospiza melodia) that were tutored with playback of adult songs during the critical period for song learning. ... Full text Cite

Are Song Sparrow 'Soft Songs' Adapted for Short-range Communication?

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · March 1, 2017 Link to item Cite

Overproduction and attrition: the fates of songs memorized during song learning in songbirds

Journal Article Animal Behaviour · February 1, 2017 Most songbirds learn their songs through imitation. However, what a male sings as an adult is not necessarily a complete inventory of what he memorized at some earlier point in time: songbirds commonly memorize more material than they eventually sing as ad ... Full text Cite

A test for repertoire matching in eastern song sparrows

Journal Article Journal of Avian Biology · March 1, 2016 Repertoire matching occurs when one songbird replies to another with a song type that the two birds share. Repertoire matching has previously been demonstrated to occur at well above chance levels in a western population of song sparrows, where it is hypot ... Full text Cite

Quiet threats: Soft song as an aggressive signal in birds

Journal Article Animal Behaviour · July 1, 2015 Theory suggests that aggressive signals must be costly if they are to be reliable. Recent research in birds has shown, however, that in many species the best predictors of impending attack are low-amplitude vocal signals, soft songs or soft calls, that see ... Full text Cite

Genetic diversity does not explain variation in extra-pair paternity in multiple populations of a songbird.

Journal Article Journal of evolutionary biology · May 2015 Many songbirds are socially monogamous but genetically polyandrous, mating with individuals outside their pair bonds. Extra-pair paternity (EPP) varies within and across species, but reasons for this variation remain unclear. One possible source of variati ... Full text Cite

Social complexity as a driver of communication and cognition

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · April 1, 2015 Link to item Cite

Context-dependent categorical perception in a songbird.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · February 2015 Some of the psychological abilities that underlie human speech are shared with other species. One hallmark of speech is that linguistic context affects both how speech sounds are categorized into phonemes, and how different versions of phonemes are produce ... Full text Cite

Perceptions of Competence, Strength, and Age Influence Voters to Select Leaders with Lower-Pitched Voices.

Journal Article PloS one · January 2015 Voters prefer leaders with lower-pitched voices because they are perceived as stronger, having greater physical prowess, more competent, and having greater integrity. An alternative hypothesis that has yet to be tested is that lower-pitched voices are perc ... Full text Open Access Cite

Developmental stress, song-learning, and cognition.

Journal Article Integrative and comparative biology · October 2014 The evolution of enhanced cognitive ability has sometimes been attributed to sexual selection. An association between the mating success of males and their cognitive ability could arise either through male-male competition or through female choice. Specifi ... Full text Open Access Cite

The evolution of vocal learning.

Journal Article Current opinion in neurobiology · October 2014 Vocal learning, in which animals modify their vocalizations to imitate those of others, has evolved independently in scattered lineages of birds and mammals. Comparative evidence supports two hypotheses for the selective advantages leading to the origin of ... Full text Cite

Typical versions of learned swamp sparrow song types are more effective signals than are less typical versions.

Journal Article Proceedings. Biological sciences · June 2014 The learned songs of songbirds often cluster into population-wide types. Here, we test the hypothesis that male and female receivers respond differently to songs depending on how typical of those types they are. We used computational methods to cluster a l ... Full text Cite

Effects of early auditory experience on the development of local song preference in female swamp sparrows

Journal Article Behavioral Ecology and Sociobiology · March 1, 2014 A growing number of studies show that learning about male mating signals can shape the way females discriminate among males and may influence the evolution of both female preferences and the male traits under selection. Female songbirds commonly prefer loc ... Full text Cite

Cognitive performance predicts strength of sexual preference in a songbird

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · January 1, 2014 Link to item Cite

A possible trade-off between song and a cognitive metric in song sparrows

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · January 1, 2014 Link to item Cite

Aggressive Signaling in Song Sparrows and Other Songbirds

Journal Article · January 1, 2014 Aggressive signaling is integral to territory defense in most animals that defend territories. Territorial signals may communicate a territory owner's level of aggressive intent, announce its fighting ability, or simply proclaim ownership. Song sparrows (. ... Full text Cite

A test of a hierarchical signalling model in song sparrows

Journal Article Animal Behaviour · August 1, 2013 Hierarchical signalling may be a common adaptation for aggressive signalling. In this strategy an animal progresses through a series of discretely different signals of escalating level of threat before eventually proceeding to physical aggression. A model ... Full text Cite

Male response to an aggressive visual signal, the wing wave display, in swamp sparrows

Journal Article Behavioral Ecology and Sociobiology · April 1, 2013 Signaling often involves complex suites of behaviors that incorporate different sensory modalities. Whatever modality is used to establish that a signal functions in communication researchers must demonstrate that receivers respond to it. The territory def ... Full text Cite

How reliable is song learning accuracy as a signal of male early condition?

Journal Article The American naturalist · December 2012 That many species of songbirds learn their songs imitatively is well established, but it is less clear why they do so. A component of the developmental-stress hypothesis posits that young males in good condition learn songs more accurately than males in po ... Full text Cite

Songbirds learn songs least degraded by environmental transmission.

Journal Article Biology letters · October 2012 Communication depends on accurate reception of signals by receivers, and selection acts on signals to transmit efficiently through the environment. Although learnt signals, such as birdsong, vary in their transmission properties through different habitats, ... Full text Cite

Sensory Constraints on Birdsong Syntax: Neural Responses to Swamp Sparrow Songs with Accelerated Trill Rates.

Journal Article Anim Behav · June 2012 Both sensory and motor mechanisms can constrain behavioral performance. Sensory mechanisms may be especially important for constraining behaviors that depend on experience, such as learned birdsongs. Swamp sparrows learn to sing by imitating the song of a ... Full text Link to item Cite

The receiver-dependent cost of soft song: A signal of aggressive intent in songbirds

Journal Article Animal Behaviour · June 1, 2012 Social costs are one mechanism whereby reliability in signalling systems can be maintained. We measured the strength of aggressive response to territorial playback to ask whether the reliability of 'soft song', a strongly aggressive signal in the song spar ... Full text Cite

Limits to reliability in avian aggressive signals

Journal Article Behaviour · 2012 Cite

Song repertoire size in male song sparrows correlates with detour reaching, but not with other cognitive measures

Journal Article Animal Behaviour · June 1, 2011 Song learning is a cognitive task in which juvenile birds acquire, store and use information about adult song to shape their own song production. Comparative studies show that across bird species, performance on different cognitive tasks is usually positiv ... Full text Cite

Discrimination of vocal performance by male swamp sparrows

Journal Article Behavioral Ecology and Sociobiology · April 1, 2011 In aggressive communication, the interests of signalers and receivers are directly opposed, presenting a challenge to the maintenance of reliable signaling. Index signals, whose production is constrained by physical ability, offer one solution to the relia ... Full text Cite

Are better singers smarter?

Journal Article Behavioral Ecology · January 1, 2011 Full text Cite

Persistent representation of juvenile experience in the adult songbird brain.

Journal Article J Neurosci · August 4, 2010 Juveniles sometimes learn behaviors that they cease to express as adults. Whether the adult brain retains a record of experiences associated with behaviors performed transiently during development remains unclear. We addressed this issue by studying neural ... Full text Link to item Cite

Female response to song reflects male developmental history in swamp sparrows

Journal Article Behavioral Ecology and Sociobiology · April 14, 2010 One explanation for why female songbirds attend to male song is that the quality of a male's song is associated with the quality of his developmental history. We tested this hypothesis by playing back to female swamp sparrows (Melospiza georgiana) songs re ... Full text Cite

The evolution of animal communication: Reliability and deception in signaling systems

Journal Article The Evolution of Animal Communication: Reliability and Deception in Signaling Systems · January 1, 2010 Gull chicks beg for food from their parents. Peacocks spread their tails to attract potential mates. Meerkats alert family members of the approach of predators. But are these--and other animals--sometimes dishonest? That's what William Searcy and Stephen N ... Cite

Female sparrows use song to assess male developmental history

Journal Article Behavioral Ecology and Sociobiology · 2010 Cite

Swamp sparrows modulate vocal performance in an aggressive context.

Journal Article Biology letters · April 2009 Vocal performance refers to the proficiency with which a bird sings songs that are challenging to produce, and can be measured in simple trilled songs by their deviation from an upper bound regression of frequency bandwidth on trill rate. Here, we show tha ... Full text Cite

Neural correlates of categorical perception in learned vocal communication.

Journal Article Nat Neurosci · February 2009 The division of continuously variable acoustic signals into discrete perceptual categories is a fundamental feature of vocal communication, including human speech. Despite the importance of categorical perception to learned vocal communication, the neural ... Full text Link to item Cite

Sexual selection and the evolution of animal signals

Journal Article · January 1, 2009 Sexual selection is natural selection due to variation in mating success. Sexual selection acting through female choice of mates has been extremely important in shaping the evolution of animal communication. Females of many species show preferences based o ... Full text Cite

Soft song in song sparrows: Acoustic structure and implications for signal function

Journal Article Ethology · July 1, 2008 In many species of songbirds, males sometimes produce songs at distinctly lower amplitude than in normal singing. Depending on the species, these 'soft songs' may be sung in the context of female courtship, male-male aggression, or both. In song sparrows, ... Full text Cite

Is bird song a reliable signal of aggressive intent? A reply

Journal Article Behavioral Ecology and Sociobiology · May 1, 2008 We advocate assessing the reliability of signals of aggressive intent by eliciting aggressive signaling from a subject, giving the subject an opportunity to attack a model, and testing whether the subject's displays predict a subsequent attack. Using this ... Full text Cite

Testing the function of song-matching in birds: Responses of eastern male song sparrows Melospiza melodia to partial song-matching

Journal Article Behaviour · March 1, 2008 Song-matching has been hypothesized to be a signal of aggressive intentions whereby matching an opponent signals that the singer is likely to attack. Theory predicts that an aggressive signal should impose a cost that enforces the signal's reliability. A r ... Full text Cite

Reliable aggressive signalling in swamp sparrows

Journal Article Animal Behaviour · February 1, 2008 Whether aggressive displays are reliable predictors of attack is an important, unresolved issue in animal communication research. Here we test the extent to which vocal and visual displays predict subsequent attack in territorial male swamp sparrows, Melos ... Full text Cite

Precise auditory-vocal mirroring in neurons for learned vocal communication.

Journal Article Nature · January 17, 2008 Brain mechanisms for communication must establish a correspondence between sensory and motor codes used to represent the signal. One idea is that this correspondence is established at the level of single neurons that are active when the individual performs ... Full text Link to item Cite

Bird song and the problem of signal reliability

Journal Article American Scientist · 2008 Cite

Bird song and the problem of honest communication

Journal Article American Scientist · January 1, 2008 Most animals communication information about their fitness through vocalizations directed to potential mates and competitors alike. Signal reliability is now a central question in animal behavior. Researchers are studying signaling in male song sparrows wh ... Full text Cite

Soft song in song sparrows: Response of males and females to an enigmatic signal

Journal Article Behavioral Ecology and Sociobiology · June 1, 2007 Low-amplitude "soft song" is used by a variety of songbirds; in some species during aggressive encounters, in others during courtship, and yet others in both these contexts. In song sparrows (Melospiza melodia), soft song has thus far been observed only in ... Full text Cite

Song type sharing and territory tenure in eastern song sparrows: implications for the evolution of song repertoires

Journal Article Animal Behaviour · April 1, 2007 Song repertoires are thought to have evolved by sexual selection, with larger repertoires being advantageous in both female choice and territory defence. While most hypotheses of repertoire evolution treat different song types as functionally equal, an alt ... Full text Cite

Signal interception and the use of soft song in aggressive interactions

Journal Article Ethology · September 1, 2006 Song sparrows, like many species of songbirds, produce songs of especially low amplitude during aggressive contests. Such 'soft songs' have been shown to be reliable signals of intention to attack in song sparrows. Low intensity is a paradoxical feature in ... Full text Cite

Bird song as a signal of aggressive intent

Journal Article Behavioral Ecology and Sociobiology · June 1, 2006 A central question in animal communication research concerns the reliability of animal signals. The question is particularly relevant to aggressive communication, where there often may be advantages to signaling an exaggerated likelihood of attack. We test ... Full text Cite

Partial song matching in an eastern population of song sparrows, Melospiza melodia

Journal Article Animal Behaviour · January 1, 2005 One hypothesis for the function of vocal repertoires in songbirds is that singing multiple song types facilitates song matching, a behaviour in which one male replies to a rival's song with a song of the same type. In eastern populations of song sparrows, ... Full text Cite

Calibration of song learning targets during vocal ontogeny in swamp sparrows, Melospiza georgiana

Journal Article Animal Behaviour · October 1, 2004 Song learning in songbirds often includes an extended sensorimotor phase, in which birds gradually refine their vocal output to produce accurate copies of previously memorized song models. Increasing accuracy of song model reproduction during this phase oc ... Full text Cite

Song function and the evolution of female preferences: why birds sing, why brains matter.

Journal Article Annals of the New York Academy of Sciences · June 2004 Analyzing the function of song and its evolution as a communication signal provides an essential backdrop for understanding the physiological and neural mechanisms responsible for song learning, perception, and production. The reverse also is true-understa ... Full text Cite

Effects of early nutrition on growth rate and adult size in song sparrows Melospiza melodia

Journal Article Journal of Avian Biology · May 1, 2004 We manipulated the quantity of food provided to hand-reared song sparrows Melospiza melodia from 3 to 18 days post-hatching, a period when young birds in the wild are especially likely to experience nutritional stress. A control group was given unlimited f ... Full text Cite

Performance limits on birdsong

Journal Article · January 1, 2004 This chapter aims to explore how recent advances in our understanding of vocal production mechanisms might inform our understanding of the evolution of bird vocalizations. Analysis of the relationship between mechanism and evolution in biology has a venera ... Full text Cite

Individual variation in the strength of territory defense in male song sparrows: Correlates of age, territory tenure, and neighbor aggressiveness

Journal Article Behaviour · January 1, 2004 In many species, the ability to defend a territory is essential for a male to obtain any reproductive success at all, and even among territorial individuals, variation in the strength of territory defense could have a significant impact on how much reprodu ... Full text Cite

Beaks, adaptation, and vocal evolution in Darwin's finches

Journal Article BioScience · January 1, 2004 Darwin's finches are well known for their remarkable diversity in beak form and function. Field studies have shown that beaks evolve by natural selection in response to variation in local ecological conditions. We posit a new hypothesis: As a consequence o ... Full text Cite

Vocal performance influences female response to male bird song: An experimental test

Journal Article Behavioral Ecology · January 1, 2004 Female songbirds are thought to assess males based on aspects of song, such as repertoire size or amount of singing, that could potentially provide information about male quality. A relatively unexplored aspect of song that also might serve as an assessmen ... Full text Cite

Phonology and geographic song discrimination in song sparrows

Journal Article Ethology · January 1, 2003 We investigated whether song sparrows discriminate foreign from local songs using specific phonologic markers, a mechanism of geographic discrimination previously described for some other songbirds. Song sparrows from Linesville, Pennsylvania (PA) respond ... Full text Cite

Brain development, song learning and mate choice in birds: a review and experimental test of the "nutritional stress hypothesis".

Journal Article Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology · December 2002 The nutritional stress hypothesis explains how learned features of song, such as complexity and local dialect structure, can serve as indicators of male quality of interest to females in mate choice. The link between song and quality comes about because th ... Full text Cite

Quality of song learning affects female response to male bird song.

Journal Article Proceedings. Biological sciences · September 2002 Bird song is unusual as a sexually selected trait because its expression depends on learning as well as genetic and other environmental factors. Prior work has demonstrated that males who are deprived of the opportunity to learn produce songs that function ... Full text Cite

Individual variation in response to simulated territorial challenge among territory-holding song sparrows

Journal Article Journal of Avian Biology · September 1, 2002 Lack (1946) suggested that male songbirds exhibit consistent individual differences in the vigor or manner in which they defend their territories against intrusion. The causes and consequences of such individual variation have not been incorporated into mo ... Full text Cite

Geographic song discrimination in relation to dispersal distances in song sparrows.

Journal Article The American naturalist · March 2002 Whether geographic variation in signals actually affects communication between individuals depends on whether discriminable differences in signals occur over distances that individuals move in their lifetimes. We measure the ability of song sparrows (Melos ... Full text Cite

Auditory representation of the vocal repertoire in a songbird with multiple song types.

Journal Article Proc Natl Acad Sci U S A · October 23, 2001 Neural mechanisms for representing complex communication sounds must solve the problem of encoding multiple and potentially overlapping signals. Birdsong provides an excellent model for such processing, in that many songbird species produce multiple song t ... Full text Link to item Cite

Using "the organism" as a conceptual focus in an introductory biology course

Journal Article American Biology Teacher · January 1, 2001 Full text Cite

The evolution of bird song: Male and female response to song innovation in swamp sparrows

Journal Article Animal Behaviour · January 1, 2001 Closely related species of songbirds often show large differences in song syntax, suggesting that major innovations in syntax must sometimes arise and spread. Here we examine the response of male and female swamp sparrows, Melospiza georgiana, to an innova ... Full text Cite

Nestling growth and song repertoire size in great reed warblers: evidence for song learning as an indicator mechanism in mate choice.

Journal Article Proceedings. Biological sciences · December 2000 Females of many songbird species show a preference for mating with males that have larger song repertoires, but the advantages associated with this preference are uncertain. We tested the hypothesis that song complexity can serve as an indicator of male qu ... Full text Cite

Vocal tract function in birdsong production: experimental manipulation of beak movements.

Journal Article The Journal of experimental biology · June 2000 Kinematic analyses have demonstrated that the extent to which a songbird's beak is open when singing correlates with the acoustic frequencies of the sounds produced, suggesting that beak movements function to modulate the acoustic properties of the vocal t ... Full text Cite

Geographic variation in the organization of Song Sparrow repertoires

Journal Article Auk · January 1, 2000 We asked whether geographic variation exists in the complexity of song repertoires in Song Sparrows (Melospiza melodia) by quantitatively comparing four measures of repertoire organization across four geographically distant populations: (1) repertoire size ... Full text Cite

Song type variants and aggressive signaling

Journal Article Behav. Ecol. Sociobiol · 2000 Cite

Auditory encoding of multiple song types in the swamp sparrow

Journal Article Soc. Neurosci. Abstracts · 2000 Cite

Song type variants and aggressive context

Journal Article Behavioral Ecology and Sociobiology · January 1, 2000 We asked whether switching among song type variants functions as a graded signal of aggression in song sparrows (Melospiza melodia). Song type variants are different versions of a given song type and are defined by much smaller acoustic differences than th ... Full text Cite

Song types as fundamental units in vocal repertoires.

Journal Article Animal behaviour · July 1999 We investigated whether song types function as fundamental units of song variation in song sparrows, Melospiza melodia. As the size of a male song sparrow's repertoire increases, so does the mean similarity of his song types, as measured by the sharing of ... Full text Cite

Permissiveness in the learning and development of song syntax in swamp sparrows.

Journal Article Animal behaviour · July 1999 Vocal learning in swamp sparrows, Melospiza georgiana, is subject to a host of sensory and motor limitations. One such limitation is that young swamp sparrows almost invariably crystallize their songs with a simple trilled syntax, irrespective of the synta ... Full text Cite

The development of within-song type variation in song sparrows.

Journal Article Animal behaviour · June 1999 We investigated the development of within-song type variation in song sparrows, Melospiza melodia, with two experiments designed to determine how exposure to within-type variation influences the song-learning process and whether within-type variation itsel ... Full text Cite

The development of song variation in song sparrows.

Journal Article Anim. Behav. · 1999 Cite

Sexual selection limits evolutionary innovation in birdsong.

Conference AMERICAN ZOOLOGIST · January 1, 1999 Link to item Cite

Song-type sharing in song sparrows: Implications for repertoire function and song learning

Journal Article Behavioral Ecology and Sociobiology · June 1, 1998 One hypothesis for the function of song repertoires is that males learn multiple song types so that they may share songs with neighbors, allowing them to match during territorial interactions. In at least one song sparrow population, in Washington, territo ... Full text Cite

Song learning, early nutrition and sexual selection in

Journal Article American Zoologist · January 1, 1998 SYNOPSIS. The developmental processes through which songbirds acquire their species-typical songs have been well-studied from a proximate perspective, but less attention has been given to the ultimate question of why birds learn to sing. We present a new h ... Full text Cite

The territory defense function of song in song sparrows: A test with the speaker occupation design

Journal Article Behaviour · January 1, 1998 Territory defense is considered one of the primary functions of bird song, but this hypothesis has been directly tested in only a few cases. We used the speaker replacement method to ask whether song functions as a 'keep out' signal in song sparrows, a spe ... Full text Cite

Call learning in black-capped chickadees (Parus atricapillus): The role of experience in the development of 'chick-a-dee' calls

Journal Article Ethology · January 1, 1998 The role of learning in the development of bird vocalizations other than territorial song is not well studied. The well-known role of direct imitation in the development of territorial song potentially masks the effects of other processes in the developmen ... Full text Cite

Percussive foraging: Stimuli for prey location by aye-ayes (Daubentonia madagascariensis)

Journal Article International Journal of Primatology · January 1, 1998 Aye-ayes (Daubentonia madagascariensis) use the thin middle finger to tap on wood in search of subsurface cavities containing insect larvae. When a cavity is located, they gnaw away wood until the prey can be extracted. Previous researchers suggested that ... Full text Cite

The response of male and female song sparrows to geographic variation in song

Journal Article Condor · January 1, 1997 We tested female and male Song Sparrows (Melospiza melodia) from a Pennsylvania site for discrimination between local songs and foreign songs recorded in New York. In Experiments 1 and 2 we measured the copulatory response of female Song Sparrows to playba ... Full text Cite

Development of tonal quality in birdsong: Further evidence from song sparrows

Journal Article Ethology · January 1, 1996 Song sparrow (Melospiza melodia) songs are composed largely of pure- tone notes. Song sparrows raised in acoustic isolation (i.e, never hearing conspecific songs) tend to produce half of their notes with harmonic overtones, an atypical tonal structure, sug ... Full text Cite

Responses to songs with altered tonal quality by adult song sparrows (melospiza melodia)

Journal Article Behaviour · January 1, 1996 Pure-tone sounds are a common and distinctive feature of many birdsongs. We used field playback experiments to test whether this tonal quality is perceptually salient to adult male song sparrows in the context of song recognition, by comparing responses to ... Full text Cite

Ontogeny of vocal tract movements during song production in song sparrows

Journal Article Animal Behaviour · January 1, 1995 When adult songbirds sing, movements of the beak and other elements of the vocal tract are closely coordinated with the activity of the syrinx. The physical configuration of the vocal tract affects the tonal quality of sounds originating at the syrinx, and ... Full text Cite

Discrimination of song types and variants in song sparrows

Journal Article Animal Behaviour · January 1, 1995 Male song sparrows, Melospiza melodia, sing highly variable songs. Traditionally, researchers have partitioned this variability by assigning songs to discrete categories termed 'song types', but researchers also have recognized that songs classified as the ... Full text Cite

Temporal patterning of within-song type and between-song type variation in song repertoires

Journal Article Behavioral Ecology and Sociobiology · May 1, 1994 In many songbird species, males sing a repertoire of distinct song types. Song sparrows typically are described as having repertoires of about a dozen song types, but these song types are themselves quite variable and some songs are produced that appear in ... Full text Cite

Kinematics of birdsong: functional correlation of cranial movements and acoustic features in sparrows.

Journal Article The Journal of experimental biology · September 1993 The movements of the head and beak of songbirds may play a functional role in vocal production by influencing the acoustic properties of songs. We investigated this possibility by synchronously measuring the acoustic frequency and amplitude and the kinemat ... Full text Cite

Seasonal changes in vocalization during behavior of the Atlantic bottlenose dolphin

Journal Article Estuaries · January 1, 1993 Four vocalizations (whistles, buzzes, quacks, and pops) were quantified during three behavioral categories (socializing, traveling, and feeding) of the bottlenose dolphin in the Newport River Estuary, North Carolina. This study tested the hypothesis that s ... Full text Cite

Song Sparrows Learn from Limited Exposure to Song Models

Journal Article The Condor · November 1992 Full text Cite

Birdsong: motor function and the evolution of communication

Journal Article Seminars in Neuroscience · January 1, 1992 Communication differs from other behaviors in the potential for an arbitrary relationship between a signal's function and the motor patterns used to produce it. Also, signals often incorporate motor patterns that have been co-opted from non-signal behavior ... Full text Cite

Is the Tonal Quality of Birdsong Learned? Evidence from Song Sparrows

Journal Article Ethology · January 1, 1992 Song sparrow (Melospiza melodia) songs are composed largely of pure‐tonal sounds. This paper investigates the role that learning plays in the development of the tonal structure of song sparrow songs, as well as the role that tonal quality plays in determin ... Full text Cite

The Organization of Song Repertoires in Song Sparrows: Themes and Variations

Journal Article Ethology · January 1, 1992 Although songtypes are generally considered to be important functional units in birdsong, they have not been well‐characterized in terms of within‐ and between‐songtype variation. We analyzed the song repertoires of 12 adult male song sparrows (Melospiza m ... Full text Cite

Pitch Production in Carolina Chickadee Songs

Journal Article The Condor · February 1991 Full text Cite

PITCH PRODUCTION AND PERCEPTION IN CAROLINA CHICKADEE SONGS

Conference AMERICAN ZOOLOGIST · January 1, 1991 Link to item Cite

Testosterone induction of song in photosensitive and photorefractory male sparrows.

Journal Article Hormones and behavior · December 1989 Song in male songbirds is activated by the sex steroid testosterone (T). Using male song sparrows (Melospiza melodia), we compared effects of T in the normal spring state of photosensitivity (i.e., when the pituitary-gonadal axis is sensitive to stimulatio ... Full text Cite

Vocal plasticity in captive black-capped chickadees: the acoustic basis and rate of call convergence

Journal Article Animal Behaviour · January 1, 1989 During the winter months, the acoustic structure of the 'chick-a-dee' call of black-capped chickadees, Parus atricapillus, is similar among flock members but varies significantly between different flocks. To investigate the process of within-flock converge ... Full text Cite

How do birds sing?

Journal Article Music Perception · 1988 Cite

Vocal tract resonances in oscine bird sound production: evidence from birdsongs in a helium atmosphere.

Journal Article Nature · January 1987 The complexity and dependence on learning of many bird sounds have suggested parallels between birdsong and human speech, but the mechanisms by which each is produced have been supposed to differ markedly. In human speech, resonances of the vocal tract are ... Full text Cite

Bilateral syringeal coupling during phonation of a songbird.

Journal Article The Journal of neuroscience : the official journal of the Society for Neuroscience · December 1986 The syrinx of oscine birds ("true songbirds") is a double vocal organ, and each side has generally been presumed to function independently under separate neural control during phonation. A significant counterexample is demonstrated here in the production o ... Full text Cite

Bilateral syringeal interaction in vocal production of an oscine bird sound.

Journal Article Science (New York, N.Y.) · March 1986 The vocal organ, or syrinx, of oscine birds has two parts, each of which has generally been presumed to operate independently of the other. A significant counter-example is now demonstrated in the production of a common vocalization by the black-capped chi ... Full text Cite

A question of identity: the call of the black-capped chickadee

Journal Article Living Bird Quart. · 1984 Cite

Flock-specific recognition of chickadee calls

Journal Article Behavioral Ecology and Sociobiology · July 1, 1983 Playback tests were conducted to determine whether black-capped chickadee (Parus atricapillus) flocks recognize the difference between their own calls and those of another flock. The 'chick-a-dee' call of the species includes flock-specific acoustic differ ... Full text Cite

Spider web protection through visual advertisement: Role of the stabilimentum

Journal Article Science · January 1, 1983 The conspicuous white silken adornments known as stabilimenta, which are commonly found in the orb webs of some spiders, appear to be protective devices that warn birds of the presence of webs in their flight path. Webs endowed with artificial equivalents ... Full text Cite

Predatory capture of toads by fly larvae

Journal Article Science · January 1, 1983 A natural occurrence of predation upon toads (Scaphiopus multiplicatus) by fly larvae (Tabanus punctifer) is described. The larvae lie buried in mud, seize the toads with hooked mandibles, pull them partly into the mud, and kill them by feeding on their bo ... Full text Cite

Chemical defense of a rove beetle (Creophilus maxillosus)

Journal Article Journal of Chemical Ecology · January 1, 1983 The abdominal defensive glands of C. maxillosus secrete a mixture (70μg/beetle) of isoamyl alcohol (I), isoamyl acetate (II), iridodial (III), actinidine (IV), dihydronepetalactone (VE), and (E)-8-oxocitronellyl acetate (X). When disturbed, the beetle ever ... Full text Cite

Insect repellents from vetiver oil: I. zizanal and epizizanal

Journal Article Tetrahedron Letters · January 1, 1982 On the basis of spectral data and partial syntheses, structure 1 and 2 are established for zizanal and epizizanal, two new insect-repelling aldehydes isolated from Javanese vetiver oil (Vetiveria zizanoides). © 1982. ... Full text Cite

Individual differences and within-flock convergence in chickadee calls

Journal Article Behavioral Ecology and Sociobiology · October 1, 1981 A detailed sound analysis of the Chick-adee call of the black-capped chickadee (Parus atricapillus) was performed in order to determine a basis for individual recognition and for imitation within winter flocks. During the winter of 1978-1979 members of fiv ... Full text Cite

Red cochineal dye (carminic acid): Its role in nature

Journal Article Science · January 1, 1980 Carminic acid, the well-known red dyestuff from cochineal insects (Dactylopius spp.), is a potent feeding deterrent to ants. This deterrency may be indicative of the natural function of the compound, which may have evolved in cochineals as a chemical weapo ... Full text Cite