Data from "Predicting marine habitat for marbled murrelets during breeding and non-breeding seasons in the Salish Sea, British Columbia, Canada"

<b>Abstract</b>The marbled murrelet (<i>Brachyramphus marmoratus</i>) is a small seabird that primarily resides in coastal regions along the Pacific coast of North America, and nests in old-growth forests usually within 80 km from shore. The Canadian population of marbled murrelet is listed as Threatened under the federal <i>Species at Risk Act.</i>To investigate the species' marine distribution and aid in conservation efforts, we conducted an analysis of marbled murrelet at-sea occurrence between 2000 and 2022, utilizing at-sea and marine shoreline surveys in the Canadian portion of the Salish Sea. The data were divided into breeding season (April to August) and non-breeding season (September to March)to examine the relationship between environmental covariates and the species' distribution. We considered terrestrial covariates related to suitable nesting habitat, as well as marine covariates related to Pacific sand lance (<i>Ammodytes personatus</i>) quality habitat, slope, depth, streams, tidal currents, shorelines and climate indices (NPGO). We compared marine distribution between breeding and nonbreeding seasons and predicted variations in covariate relationships between the two periods. Using a Generalized Additive Modelling approach, we found that both marine and terrestrial covariates contributed to predicting murrelet distribution during both seasons. Notably, proximity and intactness of suitable breeding habitat impacted murrelets in the breeding season, while the overall amount of nesting habitat within an 80 km radius influenced occurrence probability in the nonbreeding season. Our analysis accurately predicted distribution patterns at a resolution of 3 x 3 kmwith an AUC of 0.89 and AUPRC of 0.53 for the breeding season, and AUC of 0.88 and a AUPRC of 0.28 for non-breeding season. Overall, our study highlights both terrestrial and marine drivers that influence the marine distribution of this threatened species and aids in informing Canadian conservation efforts.<b>Data files (11 files)</b>MAMU_MarineHabitat_SS_dataset.csvMAMU_MarineHabitat_SS_prediction_grid.csvSTUDY_AREA_BUFF (all 8 shape files required to run scripts)RASTER.tif<b>Analysis scripts (4 files)</b>Breeding_Analyses_MAMU_SS_Habitat.RNonbreeding_Analyses_MAMU_SS_Habitat.RMarginaleffectsandpercentchange.RSurvey_Type_Analyses.R