Flight strategies of migrating northern bald ibises—analysis of GPS data during human-led migration flights

Abstract

In the past, studying birds in free flight has been extremely difficult, though recently developed technologies, e. g. small and light GNSS-data loggers, allow the gaining of new insights into the behaviour and flight strategies of birds. As logger weight is a limiting factor and battery size dictates the number of positional fixes, knowledge of species-specific flight strategies is still restricted. During a human led migration of fourteen juvenile Northern Bald Ibis in 2014 we could, for the first time, record a complete GNSS dataset from all flock members over a four day migration from Salzburg to Tuscany. Data was collected by the Waldrappteam, in the course of an EU-LIFE+ project. The following paper analyses this dataset. The aim of this paper is to show the different flight strategies of migratory birds and furthermore the capabilities and limitations of the used GPS-modules for the study of free-flying birds.