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The American Ornithological Society’s North American Classification Committee (NACC) has long held responsibility for arbitrating the official names of birds that occur within its area of geographic coverage. Scientific names used are in accordance with the International Code of Zoological Nomenclature (ICZN 1999); the committee has no discretion to modify scientific names that adhere to ICZN rules. English names for species are developed and maintained in keeping with the following guidelines, which are used when forming English names for new or recently split species and when considering proposals to change established names for previously known species.

Important Note: The American Ornithological Society (AOS) is currently examining and revising our procedures for reviewing proposals to change English bird names. Consequently, the North American Classification Committee (NACC) is not actively considering proposals for the sole purpose of changing English bird names, unrelated to a taxonomic revision, at this time. We will update this announcement when our revised procedures and guidelines have been established. 

A. Principles and Procedures

1. Stability of English names. The NACC recognizes that there are substantial benefits to nomenclatural stability and that long-established English names should only be changed after careful deliberation and for good cause. As detailed in AOU (1983), NACC policy is to “retain well established names for well-known and widely distributed species, even if the group name or a modifier is not precisely accurate, universally appropriate, or descriptively the best possible.” The NACC has long interpreted this policy as a caution against the ever-present temptation to ‘improve’ well-established English names and this remains an important principle. In practice, this means that proposals to the NACC advocating a change to a long-established English name must present a strongly compelling, well-researched, and balanced rationale.

2. Name change procedures. The NACC process of considering an English name change is the same as for other nomenclatural topics. NACC deliberations are proposal-based, and the committee welcomes proposals from interested members of the professional and non-professional ornithological communities. Proposals from previous years, which may be useful as models, are posted online, as are general instructions for proposal preparation and submission. Proposals to change an established English name require a 2/3 vote in favor for passage, following the committee’s long-standing policy for all proposals.

B. General Guidelines for English Bird Names

1. Orthography. English names of birds are capitalized in keeping with standard ornithological practice. As noted by Parkes (1978), capitalization also prevents ambiguity between a species name and a description in such cases as “gray flycatcher” or “solitary sandpiper”. Diacritical marks are not used in English names. With respect to the use of hyphens, the committee follows Parkes (1978).

2. Uniqueness. The English name of every species (and of named groups within species) should be unique both within the NACC region and, with occasional exceptions, globally.

3. Length of names. Names may consist of a single word or more than one word. However, modifiers must be used for single word or group names that apply to more than one species. Thus, Gray Catbird is used for Dumetella carolinensis rather than Catbird because there are other species of catbird (e.g., the closely related Black Catbird Melanoptila glabrirostris and eleven distantly related species of catbirds in the family Ptilonorhynchidae).

4. Eponyms. Eponyms, names that incorporate the name of an individual historical person, add an apostrophe “s” ending (e.g., Baird’s Sparrow, Lucy’s Warbler). Eponyms already ending in “s” also add an apostrophe “s” (e.g., Xantus’s Hummingbird).

5. Geographical names. Names based on geography may use either the adjectival (e.g., Jamaican Woodpecker) or noun (e.g., Canada Warbler) form of a name, but names should be used consistently for each geographical entity.

6. Species marginally distributed in North America.  Names generally accepted by global or regional authorities are typically used for species that occur in our area as vagrants, introduced species, or species of otherwise marginal distribution.

C. New and Modified Names Based on Changes to Classification

1. Typical species splits. In the case of true phylogenetic daughter species formerly treated as a single parental species, the usual policy is to create new names for each daughter species. For example, the split of Solitary Vireo resulted in new names for each of the three daughter species (Blue-headed, Cassin’s, and Plumbeous) rather than retention of Solitary Vireo for one of the daughters. This practice is designed to prevent confusion in the literature as to what taxonomic entity the parental name (e.g., Solitary Vireo) references. Note that this differs from the procedure used for scientific names, which mandates (via ICZN) that the name of the nominate form remain unchanged. In support of the principle of stability, the choice of new names strongly considers existing names for the daughter species in widely used older literature (e.g., Ridgway and Friedmann 1901-1946) as well as any names proposed for the new species in publications supporting the change in species limits.

1.1 Exceptions. Strong association of names with particular daughter species may provide exceptions to the above policy. In these situations, a change to the English name of one daughter species would cause much more disruption than a change to that of the other daughter species. In these cases, the potential confusion of retaining the parental name for the daughter species strongly associated with the name is weighed against the potential disruption of changing the name. Overall, the goal is to maximize stability and minimize disruption to the extent possible. The committee uses various factors to assess potential differential impact, such as major differences in range size, differences in usage in the scientific and popular literature, and relative appropriateness of a name. The Committee recognizes that such judgments are subjective and that borderline cases will inevitably occur.

1.1.a. Relative range size. In many cases, relative range size is an excellent proxy for the differential effect of a name change. When one or more new daughter species are essentially peripheral isolates or have similarly small ranges compared to the other daughter species, then the parental name is often retained for the widespread, familiar daughter species to maintain stability. For example, the English name Red-winged Blackbird was retained for the widespread species Agelaiusphoeniceus when the Cuban subspecies A.phoeniceus assimilis was elevated to species rank, and a novel English name (Red-shouldered Blackbird) was adopted only for the daughter species A. assimilis.

1.1.b. Differential usage. In some cases, a name is much more associated with one daughter species regardless of relative range size. For example, the name Clapper Rail has been consistently associated with birds of the eastern US and Caribbean for over a century, whereas populations in South America and in the western US and Mexico were known by various other names before being grouped under the name Clapper Rail. In this case, despite the extensive range of the South American daughter species (Rallus longirostris), the name Clapper Rail was retained for eastern North American daughter species (R. crepitans) when the species was split into three, with Mangrove Rail applied to the daughter in South America and Ridgway’s Rail to that in the southwestern US and adjacent Mexico (R. obsoletus).

1.1.c. Relative appropriateness. In some cases, a parental name is much more appropriate for one of the daughter species. In such cases, especially when no truly appropriate substitute name can be found, a parental name can be retained for that daughter. For example, in the case of the split of Winter Wren (Troglodytes hiemalis), the parental name Winter Wren was retained for the migratory eastern species, whereas the novel name Pacific Wren was created for the largely resident western species (T. pacificus). In this case the retained English name of the eastern species hiemalis also reflects its scientific name, which means “of winter” (Jobling 2010).

2. Other species splits. In the case of a change in species limits due to incorrect previous assessment of relationships, then the parental English name may be retained for the appropriate species, especially if no other suitable name is available. This differs from 1 above in that the changes do not involve true parent-daughter splits in the phylogenetic sense but rather a correction of previous taxonomy. For example, when Galapagos Shearwater was split from Audubon’s Shearwater, the name Audubon’s was not changed because new data revealed that Galapagos was not its sister and should never have been considered conspecific with Audubon’s in the first place; therefore, the original classification, with both species treated as separate species with their original separate names, was restored.

3. Species lumps. The committee occasionally merges two or more species into a single species. Guidelines for English names that result from lumps generally mirror those for species splits, in that a new name is generally preferred unless the exceptions for relative range size or appropriateness (as above in C.1.1 and C.1.2) apply. In practice, many lumps involve species with a great disparity in geographical range, so that in many cases the name for the more widespread former species is retained for the merged species. In a case in which the lump represents a return to species limits recognized prior to a split (i.e., in a reversal of a split), then the original name for the pre-split species is again adopted (in some cases this is the name of one of the former daughter species).

4. Reallocation of taxa at higher taxonomic levels. In the case of reallocation of taxa at the family or genus level due to new phylogenetic data, the Committee may occasionally change the group name of a species to reflect more accurately its phylogenetic relationships. A classic example is the change of the English name of the species formerly known as Upland Plover to Upland Sandpiper (to restrict the group name “plover” to the Charadriidae). Such changes are evaluated on a case-by-case basis, with assessment of the cost of loss of stability versus the benefit of increasing phylogenetic information in the name. Note that many English group names do not have phylogenetic significance even at the family level (e.g. flycatcher, warbler, finch, sparrow, tanager, grosbeak, and bunting) and are best treated as morphotypes. Thus, changes to long-standing names of this type (e.g., Scarlet Tanager) to correspond to changes in family or genus allocation generally require special circumstances. Again, the Committee recognizes that the inevitable subjectivity in these situations will create borderline situations.

D. Special Considerations

1. Eponyms. At present, 142 English names of NACC bird species are eponyms. The NACC recognizes that some eponyms refer to individuals or cultures who held beliefs or engaged in actions that would be considered offensive or unethical by present-day standards. These situations create a need for criteria to evaluate whether a long-established eponym is sufficiently harmful by association to warrant its change. After substantial deliberation and consultation, the NACC has adopted the following guidelines:

1.1 The NACC will change well-established eponyms only in unusual circumstances, but these situations may occur. The NACC recognizes that many individuals for whom birds are named were products of their times and cultures, and that this creates a gradient of disconnection between their actions and beliefs and our present-day mores. By itself, affiliation with a now-discredited historical movement or group is likely not sufficient for the NACC to change a long-established eponym. In contrast, the active engagement of the eponymic namesake in reprehensible events could serve as grounds for changing even long-established eponyms, especially if these actions were associated with the individual’s ornithological career. The NACC recognizes that opinions will often differ on how best to handle such situations, and the Committee strives to strike a balance that recognizes the principle of nomenclatural stability while respecting circumstances in which names should be reconsidered to reflect present-day ethical principles or to avoid ongoing harm.

1.2 In evaluating potential changes to eponyms, the NACC will also consider the degree of historical association between the eponym and the species it describes. Some eponyms are purely honorific in that they refer to an individual with no close association to their namesake species or to ornithology in general. Other eponyms refer to the individual who first discovered or collected that species, or to individuals who contributed substantially to advances in our discipline. These latter names have a tighter historical and ornithological affiliation and therefore a higher level of merit for retention.

2. Foreign-language names. As stated in AOU (1983), “vernacular names derived from a language other than English may be adopted when these are well established and not inappropriate.” For example, the endemic Hawaiian avifauna includes many species for which Hawaiian-language names are well established, and most of these have been incorporated into the AOS Checklist. However, in situations in which no historical Hawaiian-language name is known, the NACC will generally give precedence to an established English-derived name over a Hawaiian-language neologism. Similar principles apply to names derived from non-English languages elsewhere within the NACC area.

3. Derogatory or otherwise offensive names. English bird names that clearly denigrate any group or class of people, or which would be generally considered offensive by present-day standards, may be changed for this reason alone. For example, the English name of the duck formerly known as Oldsquaw was changed to Long-tailed Duck in the 42nd Supplement (AOU 2000). The associated text of that supplement reads in part “The Committee declines to consider political correctness alone in changing long-standing English names of birds but is willing in this instance to adopt an alternative name that is in use in much of the world.” The present policy document revises this approach to acknowledge that there may be English names that cause sufficient offense to warrant change on that basis alone. The committee will consider the degree and scope of offensiveness under present-day social standards as part of its deliberations. The NACC acknowledges that some words or terms may become secondarily offensive, even when they were not originally intended as derogatory, and sometimes even when there is no direct etymological link between the original name and its now-offensive connotation. 


American Ornithologists’ Union (AOU). 1983. Check-list of North American Birds, 6th ed. American Ornithologists’ Union, Washington, D.C.

American Ornithologists’ Union (AOU). 2000. Forty-second supplement to the American Ornithologists’ Union Check-list of North American Birds. Auk 117: 847–858.

International Commission on Zoological Nomenclature (ICZN). 1999. International Code of Zoological Nomenclature, 4th edition. International Trust for Zoological Nomenclature, London.

Jobling, J. A. 2010. Helm dictionary of scientific bird names. Christopher Helm, London.

Parkes, K. C. 1978. A guide to forming and capitalizing compound names of birds in English. Auk 95: 324-326.

Ridgway, R., and H. Friedmann. 1901-1946. The birds of North and Middle America. Bulletin US National Museum 50, parts 1-10.