DOI: 10.5061/dryad.g1jwstr1s
title: Data for: The spatial consistency and repeatability of migratory flight routes and stationary sites of individual European nightjars based on multiannual GPS tracks

description: Background: The degree to which avian migrants revisit the same sites to
 replicate routes from previous years has received more and more attention
 as the possibilities of tracking small to medium avian migrants over
 multiple annual cycles have improved. Repeated measurements of individuals
 can potentially inform about their navigation and migration strategies and
 to what extent observed variation within and between individuals may
 reflect the selective potential in the population. Methods: We analysed
 the annual space-use of European nightjars (henceforth nightjars)
 Caprimulgus europaeus tracked with GPS-loggers in multiple years between
 northern Europe and southern Africa. We quantified site-fidelity to
 stationary sites and consistency, repeatability, and latitudinal
 correlations in route choice as well as investigated barrier associated
 changes of within- and between individual longitudinal variation in flight
 routes. Results: We found that the nightjars consistently used the same
 breeding and wintering sites but that individual migratory route choice
 was flexible, although largely repeatable. Thus, rather than follow any
 flyway common to the study population nightjars followed
 individual-specific flight corridors while allowing for variation of a few
 hundred kilometres in route in both autumn and spring. Although the
 overall distribution of tracks was highly autocorrelated in both seasons
 we detected variations in longitudinal spread associated with the passage
 of ecological barriers enroute. Potential intermediate goal areas were
 detected prior to the crossing of the Mediterranean Sea and the Sahara
 Desert in both seasons. In spring, within-individual route variability
 dropped to a few tens of kilometres at the initiation of the desert
 crossing but increased to maximum over the barrier. Conclusions: The
 nightjars incorporate an individual-specific space-use within their annual
 cycle that allow for a degree of flexibility during migration, possibly
 driven by the energetical benefits of allowing adaptive wind drift while
 airborne. Our data demonstrate how topography and spatial carry-over
 effects influence flight path variability that may dimmish or reinforce
 individuality in route choice. Hence, this study highlights that
 identifying and quantifying past and present external influences on
 behaviour and realised routes can be critical to distinguishing the
 genetic basis and variation in migration.
description: GPS sampling by dataloggers on individual birds during the annual
 cycle to track migration and non-breeding movements.
description: # ME_Rep_EN_to_Dryad
 [https://doi.org/10.5061/dryad.g1jwstr1s](https://doi.org/10.5061/dryad.g1jwstr1s) ## Description of the data and file structure A file containing datetime and coordinates (Lat/Lon) with a temporal resolution up to 1 sample per day. Columns Bird Id and Tag Id identify unique bird and tag combinations. Some tags have been used on different individuals during different years. ### Files and variables #### File: ME\_Rep\_EN\_to\_Dryad.csv **Description:**  ##### Variables * datetime: timestamp of GPS fix * BirdId: Id of individual tracked * TagId: Id of  tag used * Lon: Longitude * Lat: Latitude