Introduction to online material for the evolving H&M Checklist

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Compiled for and by the Trust for Avian Systematics 

(Registered UK charity No. 1014427)

The nature of the resource

The Howard & Moore Checklist was first published in 1980. A second edition appeared in 1994, a third in 2003, and the 4th edition (2013-14) required two printed volumes (Non-Passerines pp. i-l, 1-461; Passerines pp. i-lii, 1-752, each of which provided substantial additional content in an included CD). Editions 1 and 2 were led by Richard Howard, and editions 3 and 4 by Edward Dickinson who favoured a conservative approach, e.g. where the elevation of subspecies to species rank was being promoted. In seeking to secure a long-term future for the Checklist its ownership was assigned to the Trust for Avian Systematics.

In 2015 the Trust, with the approval of Richard Howard, agreed a successor to Edward should be proposed to take on the editorship. Les Christidis, who had co-edited the 204 volume was approached, met the Trustees and was accepted.  Meanwhile, the IOC had begun to promote the idea of a single world checklist. Christidis favoured that idea and led a debate in favour of this at the IOC meeting in Vancouver in 2018, but he did not have the Trust’s backing and resigned. The Vancouver meeting seemed to have united several parties behind the idea, but the concept was disliked by those who felt that alternative views would be smothered.

The Trust was urged to collaborate in the creation of the envisaged unified checklist, but during the chairmanship of Clive Mann chose to defer any involvement – partly due to the historically conservative approach taken in 2003 and 2013/14 checklists. It also decided that it should work on a fresh edition of Howard & Moore, and six regional working groups were tasked with a careful update. As it was clear that this new edition could not be produced as a printed book the Trust set up a website and in 2019 made the 2013/14 edition available on-line, including the changes listed in the Errata and Corrigenda of the printed volumes.

Going online meant that it would be necessary to make rapid changes in all the bird families; but after a gap of at least six years there was much to revise in most of them. So, the real task became clear! We had to update a family and, once updated, we have to keep it up to date: making required and making sure putting these through our approval process. We now have our sequence of the first 26 families ‘published’, thus the TAS website now displays a composite document made up of the newly approved updates and the unchanged 2013/2014 parts of the Checklist – which are to be replaced as fast as possible.

After the initial publication of each revised/updated family all changes will see a new version date added (and the changes will be placed in a ‘log’ that will be made available separately on the website). Creating the format for the log is now an urgent task.

The 2003 edition of the H & M Checklist, more scientific than its predecessors, gave the gender of each genus and demanded that attention be paid to maintaining gender agreement for words that were variable, a task managed for us by the late Normand David and his friend Michel Gosselin. In 2013 this entailed an extra column where the V for variable could be seen in 2013. Behind this lay the strong database skills of Denis Lepage which not only made the supply of content to the printer simple, but in 2019 also allowed us to place the list on-line in 2019 in an almost identical format (but without the many important Appendices).

The print edition of 2013/2014 signalled the support of the Natural History Museum UK and of the American Museum of Natural History.

A ’sandbox version’ was quickly created as the editing needed to be stored and approved and prepared for eventual upload. This greatly facilitated the work of the above-mentioned Geographical Groups (GGs). It had to be re-coded for easy display on the Internet, and it is only now being further upgraded by the adoption of a faster, better programming language.

“Publishing on-line” is not a valid action in the eyes of the International Commission for Zoological Nomenclature because the html format is not protected. Where needed we will use e-publication with task-appropriate PDFs that are valid.

The 2021-2024 Update Team:


Alexandre Aleixo: initial Chair of the Neotropical (or South American) GG; Trustee (from 2021-22 year).

Norbert Bahr: Chair of the Afrotropical GG for the passerines (following the work on the non-passerines by the late Clive Mann).

Terry Chesser: liaison for North and Middle America.

† Normand David: Special Advisor spellings of scientific names and the gender of genera (recently deceased – and now replaced by Michel Gosselin).

Edward Dickinson: past lead author, Chair of Co-ordination [“Link”] Committee, Chairman of TAS.

Steven Gregory: Special Advisor on genus-group names, Chair of Subcommittee on family-group names; compositor for publications in Avian Systematics; TAS Trustee of long standing.

Graham Higley: past Chairman of TAS and past Hon. Treasurer. Re-elected Hon. Treasurer after a mandatory 1-year break, he has, following re-election at the August 2023 AGM he resumed the role of Hon. Treasurer. He kindly provided support during his gap year.

Julian Hume: Special Advisor on extinct and near extinct birds.

Ulf Johansson: immediate pastChair of the Western Palaearctic GG (non-passerines).

Yang Liu: Chair of the Eastern Palaearctic GG (succeeding Isao Nishiumi).

† Clive Mann: past Chairman of TAS, Chair of the Afrotropical GG (sadly now deceased).

Bob McGowan: incoming Chair of the Western Palaearctic GG (passerines), TAS Trustee (from 2022-23 year) and Hon. Secretary to the Trust  

Isao Nishiumi: initialChair of the Eastern Palaearctic GG.

Urban Olsson: Special Advisor on molecular studies and their interpretation.

Paul Scofield: Chair of the Australasian GG; and Special Advisor globally on oceanic birds.

Paul van Els: Chair of the Neotropical (i.e. South American) GG; Trustee (from 2022-23 year).

David Wells: Chair of the Asiotropical GG; Special Advisor on English names; TAS Trustee of long standing.

Trevor Worthy: editor of Avian Systematics.

GG members (excluding Chairmen)

At some point the following people volunteered to join a GG; their activity varies: 

Carlos Agne, Vladimir Arkhipov, Yuri Artukhin, Gustavo Bravo, Craig Brelsford, Gustavo Cabanne, Martin Cake, Chang-Yong Choi, Alice Cibois, Pierre-Andre Crochet, Geoffrey Davison, Glaucia Del-Rio, Ron Demey, Lu Dong, Song Gang, Juan Carlos Gonzalez, Takashi Hiraoka, Peter Hosner, Tim Inskipp, Praveen Jayadevan, Martyn Kennedy, Guy Kirwan, Evgeny Koblik, † Thomas Kuenzel, David Marques, Michael Mills, Andre Moncrieff, John Morris, Heraldo Norambuena,  Jan Ohlson, Urban Olsson, Dieter Oschadleus, Jessica A. Oswald, Thane Pratt, Paola Pulido-Santacruz, Phil Round, Roger Safford, Manuel Schweizer, Ryan Terrill, Dieter Thomas Tietze, Don Turner, Bas van Balen, Renate van den Elzen, Dick Watling, Trevor Worthy.

Database support has been provided by K.J. Duursma, Managing Director of Worldwide Webdesign, and his staff: especially senior programmer James Billinness. 

Management in action:

Before much recruitment took place, the Trustees arranged two meetings of an initial Advisory Working Group: helpful external participants were Jerome Fuchs, Lei Fumin, Michael Patten and Zhang Zheng-wang. Others were Martin Cake, Pierre Andre Crochet, Clive Mann, Paul Scofield and Trevor Worthy who were, or later became, team members.

At this early stage we needed and wanted to encourage our Geographic Groups to discuss, agree and submit proposals for change using our On-line Electronic Database. These groups have been mentioned above.

We sought to co-ordinate these GGs (of 4 to 10 people per group) through progress meetings (when appropriate, with accessible representative attendees who could spare the time) using video conferencing. This co-ordinating process was also intended to provide the Trustees of TAS with a flow of information particularly for all attending one or both of the annual meetings of the TAS Board of Trústees.  

Financial viability

The printed volumes of 2003, 2013 and 2014 provided royalties as an income. That income stream has been exhausted and the community demands on-line content.

The website currently offers all our material free of charge. At the recent EGM the Trustees approved plans to change for some on-line information; however, access to the listed taxa across all families will remain free to all. Charges will be for access to information that we do not display.

It is intended to place the following information behind a “pay wall”: (1) the lists of footnotes, (2) the lists of references and (3) other initiatives creating fresh displayable information. Access to this material will be offered to individuals under a subscription scheme.

We do not expect the pay wall to come into force until the second quarter of 2024 (when all the non-passerine families have been updated/revised and the duly published in the displayed checklist). Becoming a subscriber through an agreement to set up an automatic annual payment making a payment for a 12-month period will be rewarded by a reduced charge for Year One. We anticipate the annual subscription will be £20 so the reduced change will be £15.

There will be free team access (for agreed periods) and we will be able to grant Guest Access for those providing regular help to team members. 

We shall have a separate subscription scheme for Institutions (museums, but also universities offering courses in natural sciences thus benefitting the student body as well as the staff). This will be offered to institutional libraries at a cost of £100 per annum.

We intend to shape this offer of access so that a large institution can help a small institution in a developing country. Details have yet to be agreed; but we envisage, for example, that a large institution which commits to subscribe £100 per annum for 3 years, would be entitled to request the Trust to provide the purchaser’s nominated small institution with free access for 3 years using a special access code that we would supply.  Renewal would be negotiable.

Our website will display details of these schemes as soon as possible.

We have indicated above that we do not expect access restrictions will begin until the second quarter of 2024; but we recommend that you explore the available lists of footnotes and lists of references before January 2024 so that you can assess their potential value to you.   


Most readers will want to start from the List of Families and to select one and search within that family. From there you can choose Previous Family or Next Family oy you can go back to the List of Families. However, Control-F will bring up an empty search box on the right near the top of the page. This allows you to search for anything with the selected family.

The 2014 and 2015 volumes that contained the checklists also contain various introductory articles and appendices. Should you wish for a PDF of any one these please e-mail and request what you want. In return do please consider making a small donation: that would be much appreciated.

Checklist philosophies:

Since 2003 the Howard & Moore Checklist has chosen to be and be seen to be conservative. This is a stance we intend to retain. We believe it is important that minority views are not disregarded, and we aim to include significant minority views in our footnotes where there is a reasonable sized minority. Users, please tell us ( which such views you would like to see footnoted.

Our species concept: we retain as a basis the Biological Species Concept, but now modified by the application of integrative taxonomy drawing on multiple variables to illuminate the situation, although we may appear reluctant to approve change if appropriate molecular genetic evidence has not been found or not been taken into account.

Our adopted concept is the subject of a paper in the Notices section of the e-journal Avian Systematics which was published in July 2023.

The subspecies-group, a rank not discussed in the Code (I.C.Z.N., 1999), was initiated in North America in later volumes of the Peters Check-list, and was used by in Sibley & Monroe (1990). It serves as a signal that eventual re-ranking to species level seems likely. Noticing that in other geographical regions this had been largely ignored, but seeing value in it, we have begun to promote this globally where we see suitable cases and our GGs concur. In looking at these remember that we sequence subspecies taxa geographically – broadly from NW (e.g. Alaska) to SE (New Zealand); thus the numbering suggesting subspecies group membership may well be scattered through the list of subspecies.

In our 2013-2014 edition we quite often used terms such as superspecies and allospecies and on p. xv in 2013 we provided a reason for retaining these terms. However, there is now an alternative approach which we find more meaningful: i.e. clades as revealed by molecular studies, and these we are gradually adopting. Where clades are based on the sampling of a large majority of the relevant taxa such information will be useful when considering taxon sequencing, influenced by the number of taxa in each branch of a clade.

We aim to include footnotes that refer to the best sources of available molecular data. We may also make clear when we defer re-sequencing awaiting fresh information.

Spellings of taxon names:

See 2013 p. xvi; no change in approach.


There are many names in synonymy. Arguably a list like ours should include these. However, over most of the world compilation of complete synonymies has languished for long periods. Even such excellent lists as Zoonomen are incomplete (and occasionally incorrect). If grant funding becomes available, the Trust would like to help tackle this by associating a “synonym bank” with our checklist (in the form of a linked sister database). 

 In the meantime, our policy is to avoid repeating the names of synonyms listed in Peters Check-list; and only in exceptional cases will we mention older synonyms that were not mentioned therein.

Dates of publication:

It can be essential that a particular publication date be explored; most often this is because amongst the subspecies of a widespread species more than one may appear to be from the first year possible.

We continue to research detailed dates of publication (i.e. the month or even day within the cited year), when we see the need. In such cases we will, when possible, cited the authority for this information.

English names:

In broad terms the policy applied in 2013 (see p. xvii) stays in force, but with a tightening and simplification of rules governing, e.g., ’group’ name choice, hyphenation, elision, application of adjectives and the handling of name conservation. Nevertheless, we continue to be open to, and would welcome, discussion about achieving name usage in common across all the world lists. Ideally, when we have absorbed the full molecular genetic evidence, we should open our minds to singularising group names (e.g. those used for genera) and tackling the challenging step of eliminating conflicting usage … as now exhibited in the case of “blackbird”, for example. This requires strong leadership from the IOC (now the IOU).

Extinct taxa:

We are delighted that Julian Hume has joined our team. His work is very largely concerned with fossils, and he is helping us to include some previously overlooked names of extinct or probably extinct birds and we hope he will gradually add appropriate footnotes. We maintain the policy agreed with BirdLife in 2013, i.e. we now accept the listing of taxa considered extant from 1500 AD onwards, as set out in Appendix 5 to volume 2 of The Howard & Moore Complete Checklist of the Birds of the World, 4th edition (2014).

Range statements:

There has been a considerable amount of careful revision of range statements. But in some regions there is still considerable scope for providing more detail.

Geographical names:

Our Appendix 6 to volume 1 in 2013, included a list of accepted geographic names based on the 10th edition of The Times Comprehensive Atlas of the World, which is essentially still our base line; few names have been added.

References/Literature cited:

Our 2013/2014 Checklist included two volume-specific CDs and each included a volume-specific list of references. We have a PDF of each of these and a nice request (with or without a very modest donation) in an e-mail to that includes your e-mail address will secure you a copy of that PDF.

In the context of an on-line Checklist in database form, we have begun to provide lists of references, family by family. These can be seen in families 1-26. These derive from the lists of footnotes.

A revised footnote may or may not retain mention of earlier views and authorities. We use EndNote software to store and manage footnotes. If you need help from that repository ask us at