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Editor's Choice, Auk volume 130 issue 2

By Michael T. Murphy, Editor

The Auk Editor Michael T. Murphy offers his choice for must-read articles in the most recent issue of the Auk. In this issue, he highlights recent advances in the understanding of long-distance migration using archival light-level geolocators.
Technological advances often spawn new discoveries, and this is certainly true of avian migration. The lives of migratory birds are mysterious and complex, yet endlessly fascinating, and in the past 400 years we have come from believing that migrants hibernated or disappeared in the mud at the bottom of lakes in winter to the point of using satellites to pinpoint, in real time, exact locations of migrants 1000s of kilometers from us. Such possibilities exist only for large birds able to carry the necessary equipment. Small birds (< 100 g) were excluded from such possibilities, but a door was opened in 2009 with the publication of Bridget Stutchbury and colleagues’ paper on the use of light-level geolocators to study migration in Wood Thrush and Purple Martins. Geolocators cannot provide the details of satellite tracking, but they nonetheless represent an enormous technological advance, and studies of the migratory biology of small birds have since spread like wildfire. And so too has our knowledge of migration routes and speeds, stopover biology, overwinter site use, and population connectivity. A pattern, unbeknownst before the application of geolocators, is the use of multiple sites by overwintering migrants. Many species move 100s to 1000s of kilometers once or twice over the course of the northern winter to possibly exploit the shifting availability of resources.

In this issue of The Auk we bring together studies of migration in nine species of birds, including a first ever study of austral migration using geolocators in a South American species. The topics of study are diverse, ranging from descriptions of rate and direction of movement, unexpected lengthy use of stopover sites, to analysis of the integration of timing and location of molt with migration, and even the use of geolocators to validate migration data collected using other methods. It is our hope that this compendium stimulates further study of migration by tweaking the imaginations of current and future researchers.

Eyes Upon The World: Archival Light-level Geolocators

Long-distance Bird Migration within South America Revealed by Light-level Geolocators
Alex E. Jahn, Douglas J. Levey, Víctor R. Cueto, Jesús P. Ledezma, Diego T. Tuero, James W. Fox, and Diego Masson

Integrating Information from Geolocators, Weather Radar, and Citizen Science to Uncover a Key Stopover Area of an Aerial Insectivore
Andrew J. Laughlin, Caz M. Taylor, David W. Bradley, Dayna LeClair, Robert G. Clark, Russell D. Dawson, Peter O. Dunn, Andrew Horn, Marty Leonard, Daniel R. Sheldon, Dave Shutler, Linda A. Whittingham, David W. Winkler, and D. Ryan Norris

Prolonged Spring Migration in the Red-eyed Vireo (Vireo olivaceus)
Paul A. Callo, Eugene S. Morton, and Bridget J. M. Stutchbury

Migration Timing and Wintering Areas of Three Species of Flycatchers (Tyrannus) Breeding in the Great Plains of North America
Alex E. Jahn, Víctor R. Cueto, James W. Fox, Michael S. Husak, Daniel H. Kim, Diane V. Landoll, Jesús P. Ledezma, Heather K. LePage, Douglas J. Levey, Michael T. Murphy, and Rosalind B. Renfrew

Migration of the Common Redstart (Phoenicurus phoenicurus): A Eurasian Songbird Wintering in Highly Seasonal Conditions in the West African Sahel
Mikkel Willemoes Kristensen, Anders P. Tøttrup, and Kasper Thorup

Using Geologgers to Investigate Bimodal Isotope Patterns in Painted Buntings (Passerina ciris)
Andrea Contina, Eli S. Bridge, Nathaniel E. Seavy, Jonah M. Duckles, and Jeffrey F. Kelly

Do Archival Light-level Geolocators and Stable Hydrogen Isotopes Provide Comparable Estimates of Breeding-ground Origin?
Michael T. Hallworth, Colin E. Studds, T. Scott Sillett, and Peter P. Marra

Light-level Geolocators Reveal Strong Migratory Connectivity and Within-winter Movements for a Coastal California Swainson’s Thrush (Catharus Ustulatus) Population
Renée L. Cormier, Diana L. Humple, Thomas Gardali, and Nathaniel E. Seavy

Consistent Range-wide Pattern in Fall Migration Strategy of Purple Martin (Progne subis), Despite Different Migration Routes at the Gulf of Mexico
Kevin C. Fraser, Bridget J. M. Stutchbury, Patrick Kramer, Cassandra Silverio, John Barrow, David Newstead, Nanette Mickle, Tim Shaheen, Paul Mammenga, Kelly Applegate, Eli Bridge, and John Tautin