DOI: 10.5061/dryad.z34tmpgm6
title: Multi-colony tracking of two pelagic seabirds with contrasting flight capability illustrates how windscapes shape migratory movements at an ocean-basin scale

description: Migration is a common trait among many animals allowing the exploitation
 of spatiotemporally variable resources. It often implies high energetic
 costs to cover large distances, for example between breeding and wintering
 grounds. For flying or swimming animals, the adequate use of winds and
 currents can help reduce the associated energetic costs. Migratory
 seabirds are good models because they dwell in habitats characterized by
 strong winds while undertaking very long migrations. We tested the
 hypothesis that seabirds migrate through areas with favourable winds. To
 that end, we used a multi-colony geolocator tracking dataset of two North
 Atlantic seabirds with contrasting flight capabilities, the black-legged
 kittiwake (Rissa tridactyla) and the Atlantic puffin (Fratercula arctica),
 and wind data from the ERA5 climate reanalysis model. Both species had on
 average positive wind support during migration. Their main migratory
 routes were similar and followed seasonally prevailing winds. The general
 migratory movement had a loop-shape at the scale of the North Atlantic,
 with an autumn route (southward) along the east coast of Greenland, and a
 spring route (northward) closer to the British Isles. While migrating,
 both species had higher wind support in spring than in autumn. Kittiwakes
 migrated farther and benefited from higher wind support than puffins on
 average. The variation in wind conditions encountered while migrating was
 linked to the geographical location of the colonies. Generally,
 northernmost colonies had better wind support in autumn while the
 southernmost colonies had a better wind support in spring, with some
 exceptions. Our study helps in understanding how the physical environment
 shapes animal migration, which is crucial to further predict how migrants
 will be impacted by ongoing environmental changes.
description: # Multi-colony tracking of two pelagic seabirds with contrasting flight
 capability illustrates how windscapes shape migratory movements at an
 ocean-basin scale
 [https://doi.org/10.5061/dryad.z34tmpgm6](https://doi.org/10.5061/dryad.z34tmpgm6) The dataset contains processed data for the statistical analyses. ## Description of the data and file structure The two species are abbreviated by ATPU (Atlantic puffin, *Fratercula arctica*) and BLKI (Black-legged kittiwake, *Rissa tridactyla*). **Data used for the cluster analysis: bird\_data\_colony and bird\_data\_year** "bird\_data\_colony\_ATPU.csv" and "bird\_data\_colony\_BLKI.csv" contain one line per colony. These files were used for the cluster analysis. "bird\_data\_year\_ATPU.csv" and "bird\_data\_year\_BLKI.csv" contain one line per colony and per year. These files were used for the figures. Columns: * season: season (autumn or spring) * colony: name of the colony * year2: year, between two breeding seasons (example: 2014\_2015) * ws: wind support (in m.s<sup>-1</sup>) * cw: crosswind (in m.s<sup>-1</sup>) * wspeed: wind speed (in m.s<sup>-1</sup>) * gspeed: bird ground speed (in m.s<sup>-1</sup>) * mean\_cond: mean proportion wet per 24 h * detour: ratio between the distance covered during a migratory segment and the shortest distance between the departure and arrival location * sd.wdir: standard deviation of the wind direction based on interannual monthly wind during the study period * mon\_wspeed: scalar average wind speed based on interannual monthly wind during the study period **Data used for the linear mixed effect model to investigate the variation in wind support between seasons and species:** **bird\_data\_ringyear\_season.csv**. One row corresponds to the median value per individual, year and season. Columns: * colony: name of the colony * colony\_species: name of the colony and of the species (example: "Anda\_ATPU" for a Puffin from Anda). * year2: year of the track, between two breeding seasons (example: 2014\_2015) * ringyear: unique identifier for a track, including the ring number of the individual and an index of the deployment year (example: NOS-5187188\_1 for the first deployment of bird NOS-5187188) * ws: wind support (in m.s<sup>-1</sup>) **Colony\_coordinates:** Two files contain the colony coordinates for Kittiwakes (colony\_coordinates\_BLKI.csv) and for Puffins (colony\_coordinates\_ATPU.csv). Columns: * colony: name of the colony * col\_lon: longitude of the colony * col\_lat: latitude of the colony * ws: wind support (in m.s<sup>-1</sup>) * season: season (autumn or spring) * species: species (ATPU or BLKI) ## Sharing/Access information Tracking data from the SEATRACK project are visible online, and available on demand to the SEATRACK project: * [https://seapop.no/en/seatrack/](https://seapop.no/en/seatrack/) Contains modified Copernicus Climate Change Service information [2021]. Raw wind data come from the ERA5 model, a reanalysis model from the European Centre for medium-range weather forecast (ECMWF) and were downloaded from the climate data store: * [https://cds.climate.copernicus.eu/](https://cds.climate.copernicus.eu/) ## Code The code used for the analyses is available on Github: [https://github.com/FAmelineau/SeaWinds3](https://github.com/FAmelineau/SeaWinds3)