DOI: 10.5281/zenodo.17219417
title: Yelkouan shearwater (Puffinus yelkouan) Maltese Islands' colony differences in feather corticosterone, bulk stable isotopes, mercury concentration, adult breeding success and foraging strategies

description: All data and scripts uploaded and described here are related to the manuscript being submitted under the title: "Feather corticosterone and stable isotopes explain fledging and adult breeding success in a burrow-nesting seabird, the Yelkouan shearwater Puffinus yelkouan", accepted for publication in Marine Biology (doi: 10.1007/s00227-025-04748-8).

Adult Breeding success 

In the script “YESH_Malta_BreedingSuccess_DSR_Rmark.R” apparent breeding success and daily nest survival rates are estimated for yelkouan shearwater nests in Maltese colonies based on the nest log data found in “BreedingSuccessSummaryData.zip”.

Nestling and fledgling feather growth, corticosterone, stable isotopes and mercury

The R script “YESH_FeatherGrowth_CORT_SI_Hg_chicks_Malta_Script.R” was written to load, combine and analyse all the data related to measurements of nestling growth, feather corticosterone, bulk stable isotopes and mercury analysis. The folder “YESH_FeatherGrowth_CORT_SI_Hg_chicks_Malta_Data.zip” contains the files with these data as named and loaded in the script. The folder also contains the original outputs from the corticosterone measurements by plate, including standard curves, provided in the subfolder: “CORT_Output_by_plate”. Original outputs as sent from the LIENs laboratory for stable isotopes and mercury can be found in the subfolder “SI_Hg_Outputs”.

Adult shearwater tracking data analysis

The R script written to analyse gps-logger data is named: “YESH_RM_MJ_ChickRearPeriod_ForagingStrategies.R”

Adult yelkouan shearwater gps-logger tracking data during the chick-rearing period from the two colonies compared, Majjistral (MJ) and Rdum tal-Madonna (RM): “YESH_Malta_RM_MJ_ChickRearPeriod.csv”.

Apart from the consolidated form the tracking data from the chick-rearing period can be found on BirdLife International Seabird Tracking Database:

2012, 2013 & 2014: https://data.seabirdtracking.org/dataset/836

https://data.seabirdtracking.org/dataset/837

https://data.seabirdtracking.org/dataset/952

2019: https://data.seabirdtracking.org/dataset/1935

2021: https://data.seabirdtracking.org/dataset/2223

https://data.seabirdtracking.org/dataset/2224

2022: https://data.seabirdtracking.org/dataset/1855 

“TRACKID_2012_2022_DIAGNOSTICSV3.csv” describes the completeness of tracks based on visual assessment and is loaded during the running of the script.

Output shapefiles produced by running the script are provided in the folder: “YESH_RM_MJ_ShapefileOutputs_KDE.zip”.

Acknowledgements and Funding

We are grateful to the German Ornithologists’ Society through which all laboratory analysis was funded with funds from the Ursula Honig estate. Tracking was funded under EU-LIFE+ Malta Seabird Project (LIFE10NAT/MT/090), EU-LIFE Artina (LIFE17 NAT/HR/000594) and EU-LIFE PanPuffinus! (LIFE19 NAT/MT/000982), co-financed respectively by the Maltese Ministry for Sustainable Development, the Environment and Climate Change; Ministry of Education and Employment and Ministry for Agriculture, Fisheries and Animal Rights. All handling and sampling of shearwaters were carried out under permits from the Environment & Resources Authority (ERA) and the Wild Birds Regulation Unit (WBRU). We thank all staff and volunteers of BirdLife Malta having taken part in fieldwork, and all members of the public who contact us for grounded shearwaters. We are grateful to Gaël Guillou of the platform “Analyses isotopiques” for running the stable isotope analyses and to Maud Brault-Favrou of the platform “Analyses élémentaires” for running Hg analyses, both at the LIENSs laboratory. Thanks are due to the CPER (Contrat de Projet Etat-Région) and the FEDER (Fonds Européen de Développement Régional) for funding the AMA and the IRMS of LIENSs. Contributor PB is an honorary member of the IUF (Institut Universitaire de France).