Our knowledge of birds is daunting. Professional and amateur ornithologists have amassed a huge body of knowledge on our feathered friends. There is clearly a need for summary publications or avian encyclopedias to make this information accessible.

Efforts to review our knowledge of groups of birds goes back over a century. In 1910, the ornithologist Arthur Cleveland received a request from the Smithsonian Institution to write species-by-species accounts of North American birds to serve as a repository for current knowledge. This project dominated the last 44 years of his life.

The entire series includes 23 volumes with summaries of published information as well as Bent’s own prodigious observations. The series began in 1919 with the diving birds and concluded in 1968 with the last of the songbirds. Bent died in 1954 so the final contributions were finished by collaborators and published posthumously. What a landmark for North American ornithology.

Knowledge of North American birds continued to grow at an accelerating rate and, like any scientific publication, Bent’s work became dated.

To provide a more current summary, the American Ornithologists Union – in collaboration with ornithologists at the Academy of Natural Sciences in Philadelphia – began The Birds of North America (BNA) project. Between 1992 and 2003, 716 accounts of North American bird species were published. Each account was written by one or more ornithologists with research experience in particular species. A total of 863 ornithologists, including yours truly, contributed.

Each account follows a particular format, summarizing such topics as morphology, range, foraging behavior and diet, nesting and population dynamics. Citations to the original articles cited in the account are provided.


In 2004, the Cornell Laboratory of Ornithology provided an online version of the BNA accounts. The conversion to digital format has two big advantages. One is that each account can be updated to reflect current knowledge. Second, links to videos and sound files can be included. Access is available by paid subscription.

Cornell developed a similar resource, Neotropical Birds Online, to cover the birds of Central America and South America. The species accounts follow the BNA format.

The need for encyclopedic coverage of all the birds of the world has been met by the Handbook of the Birds of the World (HBW) project. This project consists of 16 large-format books, published between 1992 and 2013. A 17th volume on new species was added to the series.

Every bird species in the world is included. Each species is magnificently illustrated and many extraordinary photographs are included as well. Like the BNA accounts, text is provided to give our current knowledge of each species.

This project involved over 200 specialists as well as 35 illustrators and 834 photographers. The contributors hail from more than 40 countries.

Each volume is a joy to hold, read and admire. They are big books, weighing up to 10 pounds apiece. They are expensive with current prices around $150 per volume.


The Handbook of the Birds of the World publishers saw the value of making their accounts available online. In 2013, they launched HBW Alive. This web resource provides all of the species accounts presented in the hard-copy volumes. Like the digital BNA, HBW Alive is available by subscription.

The big ornithological news recently is that the online BNA and Handbook of the Birds of the World resources have been combined to provide a one-stop repository for information on any bird species. The project is called Birds of the World (birdsoftheworld.org). The site is linked to the Macaulay Library at Cornell, where thousands of videos and sound recordings of the world’s birds are available to study.

Access to the Birds of the World site is by subscription at $8 per month, $49 per year or $129 for three years. You might encourage your local library to inquire about institutional rates.

Particularly in this time of restricted travel, taking a virtual trip around the world to learn about the amazing birds on this planet is a joy. Give it a try!

Herb Wilson taught ornithology and other biology courses at Colby College. He welcomes reader comments and questions at [email protected]

Comments are not available on this story.