I. The Statutory Framework

Section 102(a) of Title 17 of the United States Code provides, in its entirety, that “copyright protection subsists, in accordance with this title, in original works of authorship fixed in any tangible medium of expression, now known or later developed, from which they can be perceived, reproduced, or otherwise communicated, either directly or with the aid of a machine or device.”¹

The statute enumerates eight categories of protected works. Category two is “musical works, including any accompanying words.” The legislative history of the 1976 Act makes clear that Congress intended this category to be interpreted broadly. The House Report accompanying the bill stated that the categories “do not necessarily exhaust the scope of ‘original works of authorship’” and were “illustrative and not limitative.”²

There are three elements to copyright protection under this provision. The work must be original. It must be a work of authorship. It must be fixed in a tangible medium of expression. The statute does not require that the author be human. It does not require that the tangible medium be paper, vinyl, or silicon. It does not require that the work be registered, published, or commercially distributed. It requires only that an original work exist and that it be fixed somewhere.

II. The Originality Standard

In 1991, the Supreme Court decided Feist Publications, Inc. v. Rural Telephone Service Co., the landmark case defining the originality threshold for copyright protection. Justice O’Connor, writing for a unanimous Court, held that originality requires two things: independent creation and a minimum degree of creativity. The creativity bar, she wrote, is “extremely low” and “even a slight amount will suffice.” The “vast majority of works make the grade quite easily, as they possess some creative spark, no matter how crude, humble, or obvious it might be.”³

Birdsong clears this threshold by a margin that would embarrass most human composers.

The Brown Thrasher (Toxostoma rufum), the state bird of Georgia, possesses a documented repertoire exceeding 1,100 distinct song types, as established by Kroodsma and Parker in their field studies of the species.⁴ Each song type consists of a unique sequence of figures—the discrete acoustic units that constitute the compositional building blocks of avian music—arranged in patterns that vary between individuals. A single Brown Thrasher male produces more distinct compositions than Mozart, who completed approximately 626 cataloged works across his entire career. The thrasher accomplishes this without formal training, without a commission, and without a publishing deal.

The Northern Mockingbird (Mimus polyglottos) maintains a repertoire of 45 to 203 song types per individual, with males continuing to add new compositions throughout their lives.⁵ Each mockingbird’s repertoire is individually assembled from a combination of original material and borrowed phrases, arranged in sequences that differ from bird to bird. A 2021 study published in the Journal of the Royal Society Interface found that mockingbirds employ compositional strategies analogous to those used by human musicians, including changes in timbre, pitch contour, and temporal patterning that researchers compared directly to techniques used by Beethoven.⁶

The Sedge Wren composes entirely original songs, generating novel acoustic sequences that have never been performed by any other individual of its species. Kroodsma documented this in a series of studies demonstrating that Sedge Wrens, unlike most songbirds, do not learn their songs from tutors but instead improvise them de novo, producing compositions that are unique in the history of their species.⁷ Under Feist, a work need only be “independently created” and possess “some minimal degree of creativity.” A Sedge Wren song satisfies both prongs with greater certainty than a phone book, and the Supreme Court spent forty-four pages explaining why a phone book was a close call.

III. The Fixation Requirement

Section 101 of the Copyright Act defines “fixed” as follows: a work is fixed in a tangible medium of expression when “its embodiment in a copy or phonorecord, by or under the authority of the author, is sufficiently permanent or stable to permit it to be perceived, reproduced, or otherwise communicated for a period of more than transitory duration.”⁸

Birdsong is fixed in the High Vocal Center of the avian brain.

The HVC, formerly known as the “Higher Vocal Center,” is a discrete nucleus in the nidopallium of the songbird brain that stores the neural representations of learned songs. Research by Hahnloser, Kozhevnikov, and Fee at MIT demonstrated that HVC neurons fire in precise, reproducible temporal sequences during singing, with individual neurons active for approximately 6 milliseconds at specific points in the song, producing a neural “score” that is replayed with millisecond precision across performances.⁹

The embodiment is stable. A song crystallized in a young bird’s HVC during the sensory learning phase remains encoded in that neural tissue for the remainder of the bird’s life, which in the case of a Brown Thrasher can exceed twelve years.¹⁰ The song can be “perceived” directly by any organism within auditory range when the bird sings it. It can be “reproduced” with the aid of a machine—specifically, the electrophysiological recording equipment used in dozens of published neuroscience studies that have decoded song representations from HVC neural activity.¹¹ A 2023 study at UC San Diego translated neural activity from the songbird brain into synthetic song in real time, demonstrating that the fixation is not merely stable but machine-readable.¹²

The statute requires that fixation be “sufficiently permanent or stable to permit it to be perceived, reproduced, or otherwise communicated for a period of more than transitory duration.” A song stored in neural tissue for twelve years is more permanently fixed than a sand mandala, a Snapchat story, or the average Broadway run. It is encoded in protein and lipid, which are at least as tangible as magnetic tape, compact disc dye layers, or the electrical charges in a flash memory chip. The Copyright Office has never required that a tangible medium be manufactured.

IV. The Musical Work

Copyright law does not define “musical work.” This is not an oversight. Congress deliberately left the term undefined to accommodate evolving forms of musical expression, a decision explained in the House Report and confirmed by decades of judicial interpretation that has extended copyright protection to electronic music, aleatoric compositions, sampling-based works, and pieces consisting of four minutes and thirty-three seconds of silence.¹³

The musicological case for birdsong is not contested by any serious researcher in the field. Birdsong consists of discrete pitches organized in temporal sequences with identifiable rhythm, melody, and in many species, harmonic structure. The Wood Thrush (Hylocichla mustelina) produces songs containing simultaneous independent pitches generated by the two sides of its syrinx—the avian vocal organ—creating harmonies that are, in strict musical terminology, polyphonic.¹⁴ The Canyon Wren descends a chromatic scale. The Musician Wren of the Amazon produces intervals that correspond to the diatonic major scale. Messiaen transcribed birdsong into classical compositions, not as artistic interpretation, but because the source material was already musical.

A 2021 interdisciplinary study by researchers in neuroscience, biology, and music philosophy at institutions including Duke University analyzed mockingbird song and identified four compositional strategies: changes in timbre, pitch contour, rhythm, and sequential ordering of phrases. The researchers explicitly noted parallels to compositional techniques in Western art music. The mockingbird, they concluded, is not merely producing sound. It is composing.⁶

The Copyright Office’s own Compendium of U.S. Copyright Office Practices states that a musical work “generally consists of a combination of melody, harmony, and/or rhythm.” Birdsong contains all three. The Compendium does not require that the combination be notated on a staff, performed on a manufactured instrument, or composed by a mammal.

V. The Repertoire Problem

The scale of the unregistered catalog is staggering.

Rosenberg et al. published in Science in 2019 the most comprehensive assessment of North American bird populations ever conducted, analyzing forty-eight years of monitoring data across 529 species. The study estimated a net loss of approximately 2.9 billion birds since 1970, representing a 29 percent decline.¹⁵ Working from pre-decline baselines and current population estimates from Partners in Flight and the North American Breeding Bird Survey, the current North American avian population stands at approximately seven billion individuals.

Not all seven billion are songbirds. Approximately 4,000 of the world’s roughly 10,000 bird species are classified as oscine passerines—the “true songbirds”—that learn their vocalizations through a process neurobiologically analogous to human speech acquisition.¹⁶ In North America, songbirds constitute the majority of the avian population. Using conservative estimates from the Breeding Bird Survey and Partners in Flight population size data, the songbird population of the United States alone exceeds three billion individuals.

If each songbird maintains an average repertoire of even fifty distinct song types—a conservative figure given that the Brown Thrasher alone holds 1,100 and the common Song Sparrow maintains 5 to 13 distinct songs¹⁷—then the total number of unregistered musical works currently fixed in avian neural tissue across the United States is on the order of 150 billion compositions. For context, the entire catalog of works registered with the U.S. Copyright Office since its founding in 1790 totals approximately 48 million registrations across all categories, including books, photographs, films, and software.¹⁸

The avian catalog outnumbers the entire registered output of human civilization by a factor of roughly three thousand.

VI. The Infringement

The existence of copyrightable birdsong would be merely a curiosity of statutory interpretation if every species composed only original material. Many do. The Sedge Wren improvises. The Henslow’s Sparrow sings a song so distinctive that no other species has been documented imitating it. The Winter Wren produces compositions of such speed and complexity—up to 36 notes per second—that the human auditory system cannot fully resolve them in real time.

But the family Mimidae exists.

The Northern Mockingbird (Mimus polyglottos)—whose Latin name translates literally to “many-tongued mimic”—has built its entire vocal identity around the systematic reproduction of other species’ copyrighted works. A single mockingbird may incorporate songs from 35 or more species into its repertoire, performing them in rapid succession during bouts that can last for hours.¹⁹ Males sing especially prolifically at night during breeding season, delivering what amounts to a continuous, unlicensed concert of reproduced material from approximately 10 p.m. to 4 a.m.

Under 17 U.S.C. § 106, the copyright holder has the exclusive right “to reproduce the copyrighted work in copies or phonorecords” and “to prepare derivative works based upon the copyrighted work.”²⁰ The mockingbird does both. It reproduces the original song—a copy fixed in its own HVC neurons—and it prepares derivative works by rearranging copied phrases into novel sequences interspersed with original material, creating what copyright law would classify as an unauthorized compilation or medley.

The reproduction is not approximate. Research has shown that mockingbird imitations are acoustically faithful enough to fool not only human listeners but the original species whose songs are being copied. Playback experiments have demonstrated that territorial males of the copied species respond to mockingbird imitations as though they were hearing a conspecific rival.²¹ The copies are, in copyright terms, substantially similar to the originals. They are, in many cases, virtually identical.

VII. The Performing Rights Catastrophe

Section 106(4) of the Copyright Act grants the copyright holder the exclusive right “to perform the copyrighted work publicly.” Under Section 101, a work is performed “publicly” when it is performed “at a place open to the public or at any place where a substantial number of persons outside of a normal circle of a family and its social acquaintances is gathered.”²²

Birds sing outdoors. Parks, forests, suburban neighborhoods, parking lots, and the National Mall are places open to the public. Every dawn chorus is a public performance. Every territorial song broadcast from the top of a street lamp at 5 a.m. in May is a public performance. The mockingbird singing from the rooftop of the Library of Congress—which houses the Copyright Office—is committing a public performance of unlicensed copyrighted material atop the building whose occupants are charged with administering the very statute being violated.

The performing rights infrastructure that governs human music is extensive. The American Society of Composers, Authors and Publishers (ASCAP) licenses approximately 18.7 million musical works on behalf of over 1,000,000 member songwriters, composers, and publishers. Broadcast Music, Inc. (BMI) represents an additional 22.4 million works. Together with SESAC and the Global Music Rights organization, these performing rights organizations collect billions of dollars annually in licensing fees from venues, broadcasters, streaming services, and any other entity that publicly performs copyrighted music.²³

Every café that plays background music pays ASCAP. Every hotel lobby, every elevator, every retail store. A bar in Tucson that allows a three-piece band to play a cover song without an ASCAP license is in violation of federal copyright law and subject to statutory damages.

A mockingbird performing 200 copied songs per day from the top of a telephone pole in that same bar’s parking lot is committing 200 acts of public performance infringement per day. The mockingbird pays no licensing fee. It has no ASCAP membership. It has no blanket license, no mechanical license, no synchronization license, and no performance rights agreement of any kind with any rights holder whose work it reproduces. The parking lot is a venue. The mockingbird is a performer. The songs are copyrighted. The performance is public. The fee is zero.

VIII. The Statutory Damages Calculation

Under 17 U.S.C. § 504(c)(1), a copyright holder may elect statutory damages in lieu of actual damages and profits. The statutory range is “not less than $750 or more than $30,000” per work infringed, as the court considers just. For willful infringement, the ceiling rises to $150,000 per work under § 504(c)(2).²⁴

The question of willfulness is not ambiguous. The Northern Mockingbird does not accidentally reproduce other species’ songs. It seeks them out. Juvenile mockingbirds enter a dedicated sensory acquisition phase during which they actively listen to surrounding species, memorize their songs, and practice reproduction over periods of weeks to months.²⁵ This is not innocent infringement. It is a deliberate, sustained campaign of acquisition and reproduction that begins in adolescence and continues for the duration of the bird’s natural life, which averages eight years and can exceed twelve.

At the willful infringement ceiling of $150,000 per work: a mockingbird that has copied 150 songs from other species carries a statutory damages exposure of $22.5 million. There are an estimated 45 million Northern Mockingbirds in the United States, according to Partners in Flight population estimates.²⁶ The collective statutory damages exposure of the American mockingbird population alone is approximately $1.0125 quadrillion.

That figure addresses only the mockingbird. It does not include the Gray Catbird, which mimics the songs of at least 44 species. It does not include the Brown Thrasher, which incorporates imitated material alongside its 1,100 original compositions. It does not include the European Starling—an introduced species, making it an unauthorized foreign performer operating without a work visa—which imitates mechanical sounds, other birds, and human speech with documented fidelity.²⁷ It does not include the approximately 200 million individual birds in the Americas belonging to species known to engage in vocal mimicry.

The aggregate statutory damages exposure across all mimetic species in the United States exceeds $30 quadrillion. The gross world product in 2025, as reported by the World Bank, was approximately $110 trillion.²⁸ The cumulative gross world product since the invention of agriculture, roughly estimated by economic historians at approximately $4.5 quadrillion in constant dollars, is insufficient to cover the liability. The birds owe more than civilization has ever produced.

IX. The Registration Gap

Under current law, registration with the U.S. Copyright Office is not required for copyright to subsist. Copyright attaches automatically upon fixation. However, 17 U.S.C. § 411(a) requires registration as a precondition to filing suit for infringement of a United States work.²⁹

No bird has ever registered a copyright. This is not because birds have not created copyrightable works. It is because the Copyright Office’s electronic registration system, eCO, requires an email address, a mailing address, and a filing fee of $65 for a single work or $85 for a group registration. The Brown Thrasher, which maintains a catalog of 1,100 works, would require either 1,100 individual registrations at a cost of $71,500, or a series of group registrations under the Copyright Office’s group registration options, which are limited to specific work categories and require that all works be published within a single calendar year.³⁰

The administrative burden is prohibitive even before addressing the identification problem. The Copyright Office requires that the applicant provide the “name of the author” and a “brief description of the deposit material.” Avian taxonomy uses Latin binomials, which the registration system would accept. But the system also requires a statement of nationality or domicile, and it is unclear whether a migratory species that breeds in Vermont and winters in Honduras can claim either jurisdiction without triggering a dispute under the Berne Convention’s national treatment provisions.

X. Conclusion

The Copyright Act of 1976 protects original works of authorship fixed in any tangible medium of expression. Birdsong is original. The Supreme Court’s own creativity standard in Feist—“even a slight amount will suffice”—is exceeded by species that compose over a thousand distinct works per individual. Birdsong is fixed. The High Vocal Center of the songbird brain stores song representations in neural protein with millisecond precision for the duration of the animal’s life. Birdsong is a musical work. It contains melody, rhythm, and in some species, polyphonic harmony. The Copyright Office’s own Compendium requires nothing more.

Approximately three billion songbirds in the United States are, at this moment, in possession of copyrighted musical compositions they have never registered and are performing publicly without authorization from any rights holder. Among them, the Northern Mockingbird—45 million individuals strong, each carrying up to 200 copied works in its neural tissue—is conducting the largest mass copyright infringement in the history of intellectual property law. It has been doing so since the Miocene epoch, approximately 25 million years before the Statute of Anne established the first copyright framework in 1710.

The Copyright Office has issued no guidance. ASCAP has collected no fees. No federal court has granted injunctive relief. The dawn chorus begins at approximately 4:30 a.m. Eastern Time, and it constitutes, under the plain text of Title 17, the single largest unauthorized public performance event in the United States. It happens every day. It has happened every day for longer than there have been days in the human calendar.

The statute is unambiguous. The science is peer-reviewed. The songs are copyrighted. The mockingbird does not care.

Ergo.