Migration routes and strategies of Grey Plovers (Pluvialis squatarola) on the East Atlantic Flyway as revealed by satellite tracking

Abstract Background While the general migration routes of most waders are known, details concerning connectivity between breeding grounds, stopover sites and wintering grounds are often lacking. Such information is critical from the conservation perspective and necessary for understanding the annual cycle. Studies are especially needed to identify key stopover sites in remote regions. Using satellite transmitters, we traced spring and autumn migration routes and connectivity of Grey Plovers on the East Atlantic Flyway. Our findings also revealed the timing, flight speed, and duration of migrations. Methods We used ARGOS satellite transmitters to track migration routes of 11 Grey Plovers that were captured at the German Wadden Sea where they had stopped during migration. Birds were monitored for up to 3 years, 2011‒2014. Results Monitoring signals indicated breeding grounds in the Taimyr and Yamal regions; important staging sites on the coasts of the southern Pechora Sea and the Kara Sea; and wintering areas that ranged from NW-Ireland to Guinea Bissau. The average distance traveled from wintering grounds to breeding grounds was 5534 km. Migration duration varied between 42 and 152 days; during this period birds spent about 95% of the time at staging sites. In spring most plovers crossed inland Eastern Europe, whereas in autumn most followed the coastline. Almost all of the birds departed during favorable wind conditions within just 4 days (27‒30 May) on northward migration from the Wadden Sea. In spring birds migrated significantly faster between the Wadden Sea and the Arctic than on return migration in autumn (12 vs. 37 days), with shorter stopovers during the northward passage. Conclusions Our study shows that satellite tags can shed considerable light on migration strategies by revealing the use of different regions during the annual cycle and by providing detailed quantitative data on population connectivity and migration timing.