DOI: 10.5061/dryad.612jm64h4
title: Where do Gyps fulvus (Griffon Vultures) feed? Combining biologging with socio-economic analysis can guide sustainable ecotourism development

description: Ecotourism supports Old World vulture conservation and raises public
 awareness of their ecological role. Traditional vulture-watching
 activities are often based at hides near supplementary feeding stations,
 where vultures predictably gather. However, identifying optimal locations
 for sustainable vulture-watching ecotourism beyond these sites is
 challenging considering that vultures travel extensive distances to locate
 carrion.  We analyzed movement data from six Gyps fulvus (Griffon
 Vultures) in northwest Sardinia, Italy, to identify areas where they
 usually feed and where economically viable birdwatching activities could
 be implemented. G. fulvus were equipped with GPS tags and tri-axial
 accelerometer sensors. Using a random forest algorithm, we identified
 feeding events from the acceleration data and fitted a Poisson process
 model to predict feeding event density across the study area.
 Additionally, we conducted structured questionnaires with 116 visitors to
 protected area (August 2022 – October 2023) to assess their willingness to
 pay for vulture-watching activities. From 2020 to 2024, we
 recorded 1,563 feeding events, primarily in areas with scarce forest cover
 and low slope, and adjacent to the main colony. Most respondents expressed
 interest in visiting observation hides and guided tours, with an average
 willingness to pay of €13–15. Based on these responses, we estimated
 potential revenues of €415.51, €41,551.27, and €415,512.72, assuming
 participation from 0.001%, 0.1%, and 1% of visitors from Germany, the
 United Kingdom, and the United States, respectively. Additional income
 from related tourism services could further increase these
 revenues. Our findings represent the first attempt to combine
 high-resolution biologging to map the foraging areas of an unpredictable
 yet ecologically significant wildlife species with data from structured
 consumer questionnaires. This approach allows for the assessment and
 potential implementation of an ecotourism model that does not depend on
 predictable supplementary feeding stations, offering ecological,
 behavioral, and sanitary advantages.
description: # Where do Gyps fulvus (Griffon Vultures) feed? Combining biologging with
 socio-economic analysis can guide sustainable ecotourism development
 Dataset DOI: [10.5061/dryad.612jm64h4](10.5061/dryad.612jm64h4) ##
 Description of the data and file structure The following zipped folder
 contains the data and software code, to replicate the analyses for the
 study entitled "Where do *Gyps fulvus* (Griffon Vultures) feed?
 Combining biologging with socio-economic analysis can guide sustainable
 ecotourism development" The script ("Script.R") replicates
 the analyses in R. Namely, the script runs a Poisson Process Model (PPM)
 in spatstat ([https://spatstat.org/](https://spatstat.org/)), to estimate
 the density of feeding events according to relevant environmental
 covariates. Analyses were carried out in R version 4.4.3 (2025-02-28) --
 "Trophy Case" This contains all the main datasets required for
 fitting the Poisson Process Model. Namely
 "Sardinia_EPSG32632.shp", "Sardinia_EPSG32632.cpg",
 "Sardinia_EPSG32632.qmd", "Sardinia_EPSG32632.shx",
 "Sardinia_EPSG32632.prj", "Sardinia_EPSG32632.dbf",
 "Sardinia_EPSG32632.shp" - The boundaries of Sardinia, in the
 epsg: 32632 CRS "FeedingEvents_Pooled_04Apr2024.Rdata" - A
 dataset of 1,563 centroids of feeding events, identified from
 accelerometers. Each row is a feeding event, characterized by the
 following variables: * "id", the identifier of each feeding
 event * "avg.timestamp", the timestamp of each feeding event *
 "week", the week of each feeding event * "month", the
 month of each feeding event * "yday", the day of the year of
 each feeding event * "lon", the longitude of each feeding event
 (epsg:4326) * "lat", the longitude of each feeding event
 (epsg:4326) * "lon.utm", the longitude of each feeding event
 (epsg:32632) * "lat.utm", the longitude of each feeding event
 (epsg:32632) "CovariatesPPM_20241016.tif" - A SpatRaster object,
 created with the terra package
 ([https://rspatial.github.io/terra/](https://rspatial.github.io/terra/)),
 containing the covariates used for point-process modeling in spatstat
 ([https://spatstat.org/](https://spatstat.org/)). The stacked raster has a
 resolution of 250 m and its layers are: * "slope", the slope of
 each cell, measured from a 250 m DEM * "dist.col", the euclidean
 distance between the centroid of each cell and the closest colony *
 "dist.sfs", the euclidean distance between the centroid of each
 cell and the closest supplementary feeding station * "dist.urb",
 the euclidean distance between the centroid of each cell and the closest
 human settlement * "dist.roads", the euclidean distance between
 the centroid of each cell and the closest road (from Geofabrik.de) *
 "tree", tree coverage according to the MODIS Terra Vegetation
 Continuous Fields Yearly Global 250m * "updrafts", the updraft
 suitability index developed by Scacco et al. (2019, see:
 [https://doi.org/10.1098/rsos.181440](https://doi.org/10.1098/rsos.181440)) * "dist.coast", the euclidea distance between the centroid of each cell and the coastline * "lon.utm", the longitude of the centroid of each cell (epsg:3262) * "lat.utm", the latitude of the centroid of each cell (epsg:3262) * "pc1", the first principal component, from PCA (see the Methods) * "pc2", the second principal component, from PCA (see the Methods) * "pc3", the third principal component, from PCA (see the Methods) * "pc4", the fourth principal component, from PCA (see the Methods) For further information about the data or the code please contact prof. Fiammetta Berlinguer ([berling@uniss.it](mailto:berling@uniss.it)) ## Funding The following study was co-financed by the European Commission through the LIFE "Under Griffon Wings" (LIFE14 NAT/IT/000484) and the LIFE "Safe for Vultures" (LIFE19 NAT/IT/000732) projects. Chiara Costantino was supported by the Italian Ministry of Education, University and Research, through the National Recovery and Resilience Plan (PNRR) - “Budget di ricerca borse 118 - Pianificazione territoriale integrata, finalizzata a massimizzare la compatibilità tra lo sviluppo delle energie rinnovabili e le comunità faunistiche della Regione Sardegna”. Grant number: UA2003DOTTRIC39_118. Ilaria Fozzi was supported by the Italian Ministry of Education, University and Research—PON ricerca innovazione 2014-2020, Azione IV.5 “Dottorati su tematiche Green”, Grant number: DOT1629893-2.