28 August 2010

Update Underway on Status Report of Least Tern in Northern America

An update is underway for the Least Tern account for the Birds of North America series, a preeminent source of information on the many species which occur on the continent.

"The original account was very well done, but a huge amount of work has been done on this species since 1997," said Casey Lott of American Bird Conservancy, who has volunteered to prepare the revised edition. "I refer to it regularly, and found sections about regional population sizes and distribution, for example, were especially out-of-date."

The 1997 version, prepared by Bruce Thompson and five coauthors, had about 230 references, Lott said. He has currently compiled more than 700 distinct sources to review for an authoritative revision.

Nesting Least Terns on the Missouri River. Courtesy of Wikipedia.

Lott has been personally involved with research on the Least Tern (Sternula antillarum) since 2004, and is currently working on an "individual-based simulation model of least tern reproduction that could be used to assess the population consequences of alternative management strategies."

"I get my head deep into the literature," Lott said, and this knowledge of the published findings, provides a familiarity with the broad range of material essential for an update to the Birds of North America account, originally issued by the Academy of Natural Sciences of Philadelphia.

"There is a great need to collect information for the right reasons," Lott said, based upon his review of a myriad of tern-related articles and reports. "A broad range of information needs to be gathered to help with conservation of the species," which is classified as threatened or endangered throughout its range in North America, which includes the Caribbean region.

For example, there is a greater need for research that directly addresses the success or failure of management responses to the common threats of habitat loss and degradation, flooding mortality due to river management, and predator and human disturbance impacts that have been identified for many years. There is also a need to focus more clearly on large populations that receive relatively little attention (e.g., breeding populations on the Red or Arkansas rivers on the Southern Great Plains or Gulf Coast populations that suffer enormous pressures from development and heavy beach use, which have been exacerbated by the Deepwater Horizon oil spill).

"I hope to especially expand the sections on conservation and management for the revision," Lott indicated. For this, he is working with four "co-revisers" to summarize the literature and insights of the many professional biologists that have worked on Least Terns over the past decade. Recently, Lott sent out a request for information to over 400 people whom he knows have been involved with tern studies, and has received a "regular flow of information" in response. Online bird forums are also being regularly checked to determine any additional sources or pertinent details.

One notable change in recent years, Lott noted, is an increase in knowledge about the distribution and abundance of Least Terns (Sternula antillarum athalassos) in the interior United States and in the Caribbean, where complete inventories of potential breeding areas have been completed only recently.

The revision - expected to be completed in a couple of years - will rely on the assistance of the co-revisors with regional knowledge of Least Tern populations in California, the Atlantic Coast, and the Gulf of Mexico Ocean, as well as the participation of Bruce Thompson, the author of the original account for the Birds of North America series, who will help to ensure continuity with the original account.

Once completed, the revised account about the Least Tern will be available online at the Academy website, which is easily accessible on a subscription basis.

The first status review for the interior Least Tern was issued in 1981 by the U.S. Fish and Wildlife Service. Since then, there has been a dramatic increase in research on the species, with a constant change in the available knowledge. The pending revision of the Bird of North America account will be a valuable addition, and will be helpful in understanding the species, and as an aid in its conservation and management.