Idiosyncratic Migrations of Black Terns (Chlidonias niger): Diversity in Routes and Stopovers. Jan van der Winden, Ruben C. Fijn, Peter W. van Horssen, Debby Gerritsen-Davidse and Theunis Piersma.
Waterbirds 37(2), June 2014. http://www.bioone.org/doi/full/10.1675/063.037.0205
By 2013, six of 27 Black Terns (Chlidonias niger) from four Dutch colonies that had received light level geolocators in 2010–2011 had been recaptured. All six recovered individuals migrated to West Africa, but whereas one individual flew there nonstop, the others made stops of varying length en route. These included flights of 2,000–6,000 km between major stopovers, achieving travel speeds over 1,000 km/day. This paper showed that Black Terns are long-distance migrants with substantial individual variation in migration patterns, including differences in the use of staging sites, stopover times and travel distances. The variation in itineraries may imply that the distribution of the marine resources they rely on are relatively unpredictable. It remains to be seen whether the variability seen here reflects differences in otherwise fixed individual strategies or whether Black Terns are truly highly flexible.