Integrative Study of Bird Song – Key Vocabulary

Thirty vocabulary flashcards summarizing critical terms and concepts from Lecture 2 on the integrative study of bird song, covering mechanisms, evolution, and adaptive significance of vocal learning.

Comparative Approach

Method that compares behavior across related species to infer ancestral traits and evolutionary changes.

Convergent Evolution

Independent evolution of similar traits or behaviors in species with distinct ancestries due to similar selection pressures.

Divergent Evolution

Evolutionary process in which related species develop different traits or behaviors because they face differing selection pressures.

Selective Pressure

Environmental factor—such as climate, predators, competition, or mating—that influences the survival or reproduction of organisms.

Proximate Question

A ‘how’ question that examines the immediate genetic, neural, hormonal, or developmental mechanisms of a behavior.

Ultimate Question

A ‘why’ question that explores the evolutionary history or adaptive value of a behavior.

Tinbergen’s Four Questions

Framework dividing behavioral explanations into development, mechanism, evolutionary history, and adaptive function.

Oscine Songbird

Member of the passerine suborder Oscines; one of the three avian groups capable of vocal learning.

Song Dialect

Population-specific variation in bird song that arises during development and can differ geographically.

Acoustic Stimulus Hypothesis

Idea that song differences arise from exposure to different sound environments during a bird’s development.

Social Interaction Hypothesis

Proposal that song differences stem from social learning with tutors present during a bird’s early life.

Genetic Differences Hypothesis

Explanation suggesting that population variation in song is due to underlying genetic divergence.

White-crowned Sparrow

Model songbird species extensively used to study song learning and dialect formation.

Spectrogram (Sonogram)

Visual representation of sound showing frequency over time and amplitude as intensity; used to analyze bird song.

Syllable (in Bird Song)

Smallest repeated sound unit in a bird’s song, visible as distinct shapes on a spectrogram.

HVC (High Vocal Center)

Forebrain nucleus critical for storing song templates and controlling song production in birds.

RA (Robust Nucleus of the Archopallium)

Motor nucleus receiving input from HVC and sending commands to the syrinx for song production.

LMAN (Lateral Magnocellular Nucleus of the Anterior Nidopallium)

Brain area involved in learning and modifying song during the developmental phase.

Area X

Basal ganglia region essential for song learning, particularly in evaluating and refining vocal output.

Song Circuit

Network of interconnected brain nuclei (HVC, RA, LMAN, Area X, etc.) governing learning and production of bird song.

Vocal Learning

Ability to modify vocal output based on auditory experience; evolved independently in oscines, parrots, and hummingbirds.

Environmental Adaptation Hypothesis

View that vocal learning enables birds to tailor songs acoustically to local habitat conditions for better transmission.

Recognition Hypothesis

Theory that vocal learning promotes individual, kin, or neighbor recognition through unique song signatures.

Information-Sharing Hypothesis

Suggestion that learning expands vocal repertoires, facilitating communication in cooperative or kin-based social groups.

Sexual Selection (in Song)

Process where complex or high-quality songs enhance male success in mate attraction or male–male competition.

Nutritional Stress Hypothesis

Cost hypothesis positing that developing the neural machinery for song learning is energetically expensive, making song quality a signal of developmental condition.

Cooperative Breeding

Social system in which multiple individuals help care for offspring; often associated with larger vocal repertoires.

Cultural Drift

Gradual change in learned behaviors, such as song, due to small inaccuracies in transmission across generations.

Adaptive Function

The fitness benefit a behavior provides, helping explain why it evolved and is maintained by natural selection.

Spiral of Animal Behavior Research

Concept that iterative study of proximate and ultimate causes leads scientists toward an increasingly integrated understanding of behavior.