DOI: 10.5061/dryad.wh70rxwr4
title: Consequences of migratory distance, habitat distribution and season on the migratory process in a short distance migratory shorebird population

description: The migratory process in birds consists of alternating periods of flight
 and fueling. Individuals of some populations make few flights and longer
 stopovers, while others make multiple flights and shorter stopovers.
 Shorebirds are known for executing marathon flights, but most populations
 studied are long distance migrants, often crossing major barriers and thus
 forced to make long non-stop flights. The sub-division of migration in
 short/medium distance migratory populations, where the total migration
 distance is shorter than documented non-stop flight capacity and routes
 offer more homogenous stopover landscape, is little explored. Here we
 combine data based on conventional light level geolocators and
 miniaturized multi sensor loggers, comprising acceleration and light
 sensors, to characterize the migratory routes and process for a
 short/medium distance (~1300-3000 km) migratory population of common
 ringed plover (Charadrius hiaticula) breeding in southern Sweden. We were
 specifically interested in the variation in number and duration (total and
 individual) of flights/stopovers between seasons and in relation to
 migration distance. Most stopovers were located along the European
 Atlantic coast. On average 4.5 flights were made during autumn migration
 irrespective of migration distance, but in spring the number of flights
 increased with distance. The equal number of flights in autumn was
 explained by that most individuals migrating farther performed one longer
 flight (all but one lasting &gt;20 hours), likely including crossing
 of the Bay of Biscay. Median flight duration was 8.7 and 5.5 hours in
 autumn and spring, respectively, and median stopover duration was ~1 day.
 Total flight duration was 36% lower in spring compared to autumn and there
 was a positive relationship with migration distance.Our results suggest
 that when suitable stopover sites are present common ringed plovers prefer
 making shorter flights even if longer flights are possible. This behaviour
 is predicted under both time and energy minimizing strategy, although the
 variable flight distances suggest a policy of time selected migration.
 Even if populations using several stopover sites seem to be more resilient
 for environmental change along the route, these results are informative
 for conservation efforts and for predicting responses to future climate
 change.
description: Light level geolocators and multi sensor data loggers.
description: # Consequences of migratory distance, habitat distribution and season on
 the migratory process in a short distance migratory shorebird population
 ## Description of the data and file structure ### Files and variables ####
 File: all.flights.csv **Description:** This data frame contain
 descriptives of all individual flights and stops/stopovers. The data is
 mainly used for descriptives. Use code in all.flights.R.  ##### Variables
 * rnr: ring number * logger: logger ID * season: season * day.start: start
 of migratory flight * day.stop: end of migratory flight  * flight.dur.h:
 flight duration (in hours) * flight.nr: flight number describing the
 individual sequential order of flight within a migration season *
 stopover.duration: stopover/stop duration (in days) *
 winter.distance.grouping: general description of distance to group
 individuals  #### File: stopover.positions.csv **Description:** This data
 frame contain mean and sd stopover positions based on geolocator data.
 Data set is used to describe the general migratory route and plot map. 
 ##### Variables * logger: logger ID * season: season * activity: stopover,
 winter or breeding position * lon: mean longitude * lat: mean latitude *
 sd.lat: standard deviation of mean longitude * sd.lon: standard deviation
 of mean latitude #### File: winter.positions.MDL.csv **Description:** Data
 frame contains data on wintering positions based on MDLs. This data set is
 used to describe wintering position, derive great circle migration
 distance and plot map.  ##### Variables * rnr: ring number * logger:
 logger ID * w.lon: mean winter longitude * w.lat: mean winter latitude  *
 sd.w.lon: standard deviation of winter longitude * sd.w.lat: standard
 deviation of winter latitude #### File: migration.perform.csv
 **Description:** This data frame contains data on summed migration
 parametes from each MDL, such as total flight and stopover duration, and
 number of migratory flights/stopovers. The data is used to test
 relationships between these aspects and migration distance. For
 descriptives and testing use code in migration.perform.R. ##### Variables
 * rnr: ring number * logger: logger ID * year: year * season: season
 (autumn/spring) * total.duration: total duration of migration in days *
 nr.flights: number of flights * flight.duration: cumulative flight
 duration * stop.duration: cumulative stopover duration * distance: great
 circle distance * z.distance: zero centered GCD. Missing data code: NA