Jet-lagged birds: longitudinal flights cause time-shifts and sun compass error
Data files
Aug 27, 2026 version files 216.76 MB
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interpolated_data_homing_id.csv
216.75 MB
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README.md
7.32 KB
Abstract
Many animals use the sun compass to guide their movement, sometimes over thousands of kilometres. Consistent use of the sun compass relies on the endogenous clock to track the sun’s arc, yet animals travelling east-west might experience mismatches between their internal clock and local time (clock-shift). Using GPS, we reveal that Manx shearwaters (Puffinus puffinus) experience such shifts during homing flights, generating predictable errors in sun compass orientation. Use of the sun compass persists even when shearwaters have access to compass-independent cues during coast-following. Our findings provide a new avenue for chronobiology research in the wild, suggest that rapid longitudinal movements may impact other processes governed by the endogenous clock, and that conserved chronobiological mechanisms impose remarkable constraints on navigation.
Dataset DOI: 10.5061/dryad.nk98sf85b
Description of the data and file structure
The data here are GPS-tracking data collected from breeding Manx shearwaters over 20 years. Shearwaters were tracked during foraging movements from their breeding islands using archival loggers or GPS-GSM devices of various designs. Devices were attached dorsally using Tesa tape and superglue. Birds were tracked for periods lasting a few days to a few weeks. The data presented here are from tracking days which were used in analysis of orientation to reveal clock-shifts and sun compass error during longitudinal homing flights. The data have already been interpolated to five-minute intervals and homing identified.
Files and variables
File: interpolated_data_homing_id.csv
Description: Tabulated GPS fix data interpolated to 5 minute intervals.
Variables
- filename: name of the original GPS track file, including metadata information.
- original_resolution_secs: median interval between fixes before interpolation in seconds.
- interpolated_resolution_secs: interval between interpolated fixes in seconds.
- track_id: numeric ID for each track.
- colony: identity of the breeding colony (cp = Copeland, lun = Lundy, ram = Ramsey, rum = Rum, sk = Skomer, skok = Skokholm).
- colony_lon: longitude at centre of colony, decimal degrees.
- colony_lat: latitude at centre of colony, decimal degrees.
- campaign: the breeding/life history stage at which the shearwater was tracked (manxCR = chick-rearing, manxinc = incubation).
- burrow: ID of the study burrow the bird was breeding in.
- ring: unique BTO metal ring number of the tracked bird.
- gps: ID of the GPS device used to track the bird.
- gls: ID of the light-level geolocator/immersion logger co-deployed with the GPS.
- datetime: date and time of interpolated fix, UTC.
- lon: longitude of interpolated fix, decimal degrees.
- lat: latitude of interpolated fix, decimal degrees.
- distance_from_last_point_km: great circle distance from last fix to current fix, in kilometres.
- time_diff_h: time difference from last fix to current fix, in hours.
- speed_kmph: speed from last fix to current fix, in kilometres per hour.
- instantaneous_gc_bearing: initial great circle bearing from current fix to the next, in degrees from north.
- gc_bearing_to_home: initial great circle bearing from current fix to the colony, in degrees from north.
- instantaneous_deflection: difference from the initial great circle bearing to home to the initial instantaneous great circle bearing, in degrees.
- in_sight: binary, TRUE = land (within the British Isles) is visible from current fix, FALSE = land is not visible from current fix.
- coastal: binary, TRUE = fix is within 30km of a major landmass within the British Isles (>20km^2).
- perpendicular_distance_to_land: distance from the fix to land, along a bearing perpendicular to the direction of travel.
- perpendicular_land_anticlock: binary, TRUE = there is land within 30km along a bearing perpendicular to the direction of travel, FALSE = there is not land within 30km along a bearing perpendicular to the direction of travel.
- jday: julian date of fix.
- date: date of fix.
- sun_azimuth: azimuth of the sun visible from each fix, in degrees from north.
- sunrise_time: time of sunrise at fix location on date of fix, UTC.
- sunset_time: time of sunset at fix location on date of fix, UTC.
- diurnal: binary, TRUE = after local sunrise and before local sunset, FALSE = before local sunrise or after local sunset.
- rolling_mean_speed_kmph: mean speed between fixes over a rolling 15 minute window.
- distance_from_home_km: great circle distance from the fix to the colony, kilometres.
- home_visible_distance: maximum distance from the colony island at which it is visible, km.
- home_visible: binary, TRUE = fix is within maximum visible distance of colony island, FALSE = fix is beyond maximum visible distance of colony island.
- out: binary, TRUE = bird is more than 3km from colony, as part of a period beyond 3km from the colony that lasts more than 2 hours, FALSE = bird is closer than 3km to the colony or is further than 3km from the colony but as part of a period lasting <= 2 hours.
- trip_id: numeric ID for each trip (i.e. each time bird is beyond 3km from home for at least 2 hours.
- track_trip_id: combined numeric track and trip IDs.
- fast_travel: binary, TRUE = rolling mean speed between fixes > 15.6kmph, threshold based on Gaussian mixture model, FALSE = rolling mean speed <= 15.6kmph.
- homing: binary, TRUE = fix is identified as part of a homing bout, FALSE = fix is not identified as part of a homing bout.
- homing_id: numeric ID for each homing bout.
- track_trip_homing_id: combined numeric track, trip and homing bout ID.
- bout_max_dist_from_home_km: distance from the colony at the start of a homing bout.
- bout_proportional_movement_to_home: change in distance from home during the bout, as a proportion of the initial distance.
- bout_deflection: the absolute deflection of the start to end bearing of the bout from the direction of the colony.
- flying: binary, TRUE = raw speed between interpolated fixes >15.5kmph, threshold based on Gaussian mixture model, FALSE = raw speed between interpolated fixes <= 15.5kmph.
- clear_beeline: binary, TRUE = no landmass between the fix and the colony, along the great circle route.
- declination: the angle of geomagnetic declination at the fix.
- coriolis_predictor: the relative magnitude of expected clockwise deflection resulting from the Coriolis effect acting on the shearwater in flight.
- time_since_sunrise: time elapsed since the bird experienced sunrise.
- lat_change: change in latitude since sunrise.
- sun_deflection: the expected sun compass error due to time-shifts resulting from longitudinal movement since sunrise.
- sunrise_lon: the longitude the bird was at during sunrise.
- sunrise_lat: the latitude the bird was at during sunrise.
- main_subset: binary, TRUE = meets criteria for inclusion in the analysis of orientation out of sight of land.
- perpendicular_land_subset: binary, TRUE = meets criteria for inclusion in the analysis of distance from land during coast-following.
- analysis_subset_id: numeric ID for each subset within a trip to be used in each analysis.
- track_trip_analysis_subset_id: numeric ID combining the analysis subset ID and the trip ID.
Code/software
Processing and analysis was conducted in R version 4.4.2. The R script used is included with this submission. All packages used are included in that script. The script includes all processing, including the processing which precedes the data included in this submission, e.g. interpolation and homing identification. The subsequent processing, statistical analysis and figure production are also included.
Access information
Other publicly accessible locations of the data:
- None
Data was derived from the following sources:
- Data on wind direction and strength were accessed from https://cds.climate.copernicus.eu/datasets/reanalysis-era5-single-levels?tab=overview