Migratory connectivity of shorebird populations from Peru

The marking of shorebirds has been used for decades to reveal key stopover sites and important migratory corridors in the hemisphere. To study this migratory connectivity, flagging is the most used technique. Birds are individually marked with a flag characterized by a country-specific color and a three-digit alphanumeric code. From 2012 to 2017, we flagged 5,071 individuals in the Paracas National Reserve, Perú: 3,346 Semipalmated sandpipers, 1,355 Western sandpipers, 155 Sanderlings and 215 Semipalmated plovers. We received 87 independent international sightings, covering all the existing migratory flyways in the Western Hemisphere. Also, we resighted two Red knots marked in the USA, one marked in Chile, and one Sanderling from Canada in Paracas. Our results confirm that most of Semipalmated sandpipers use the central corridor of the USA and Canada during both northward and southward migration from Paracas, but a few cross towards the Atlantic route northbound. Red knots migrate south through the central corridor, but at least one individual used the Pacific coast while migrating northward from Chile. Western sandpipers are restricted to the Pacific corridor during both migrations, and Sanderlings maintain their elliptical migration around the hemisphere. Semipalmated plovers use the Atlantic corridor on southward migration and the central corridor during northward migration. We found an apparent heterogeneity in the migratory behavior of each species and we postulate that there is individual variation in migratory behaviour.