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Where did the finch go? Insights from radio telemetry of the medium ground finch (Geospiza fortis)

Cite this dataset

Beausoleil, Marc-Olivier et al. (2023). Where did the finch go? Insights from radio telemetry of the medium ground finch (Geospiza fortis) [Dataset]. Dryad.


Movement patterns and habitat selection of animals have important implications for ecology and evolution. Darwin's finches are a classic model system for ecological and evolutionary studies, yet their spatial ecology remains poorly studied. We tagged and radio-tracked five (three females, two males) medium ground finches (Geospiza fortis) to examine the feasibility of telemetry for understanding their movement and habitat use. Based on 143 locations collected during a three-week period, we analysed, for the first time, home-range size and habitat selection patterns of finches at El Garrapatero, an arid coastal ecosystem on Santa Cruz Island (Galápagos). The average 95% home range and 50% core area for G. fortis in the breeding season were 20.54 ha ± 4.04 ha SE and 4.03 ha ± 1.11 ha SE, respectively. For most of the finches, their home range covered a diverse set of habitats. Three finches positively selected the dry-forest habitat, while the other habitats seemed to be either negatively selected or simply neglected by the finches. In addition, we noted a communal roosting behaviour in an area close to the ocean, where the vegetation is greener and denser than the more inland dry-forest vegetation. We show that telemetry on Darwin’s finches provides valuable data to understand the movement ecology of the species. Based on our results, we propose a series of questions about the ecology and evolution of Darwin’s finches that can be addressed using telemetry.

README: Data from: Where did the finch go? Insights from radio telemetry of the medium ground finch (Geospiza fortis)

Author Information
Corresponding Investigator
Name: Marc-Olivier Beausoleil
Institution: McGill University
Co-investigator 1
Name: Carlos Camacho
Institution 1: Instituto Pirenaico de Ecología—CSIC
Institution 2: Lund University
Co-investigator 2
Name: Julio Rabadán-González
Co-investigator 3
Name: Kristen Lalla
Institution: McGill University
Co-investigator 4
Name: Roxanne Richard
Institution: McGill University
Co-investigator 5
Name: Paola Carrion-Avilés
Institution: McGill University
Co-investigator 6
Name: Andrew P. Hendry
Institution: McGill University
Co-investigator 7
Name: Rowan D. H. Barrett
Institution: McGill University
Date of data collection:
Geographic location of data collection:
El Garrapatero, Santa Cruz Island, Galápagos, Ecuador (0°41'22.9" S, 90°13'19.7" W)
Funding sources that supported the collection of the data:
Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery and Canada Research Chair grant (A.P.H.)
NSERC Discovery Grant and Canada Research Chair grant (R.D.H.B.)
NSERC Canada Graduate Scholarship, Biodiversity, Ecosystem Services and Sustainability (BESS) NSERC CREATE (M.-O.B)
Fonds de recherche du Québec, Nature et technologies Scholarship (M.-O.B)
behaviour, communal roosting, Geospiza fortis, habitat selection, home range, spatial ecology
Recommended citation for this dataset:
Beausoleil, M.-O. et al. (2022), Where did the finch go? Insights from radio telemetry of the medium ground finch (Geospiza fortis), Dryad, Dataset,


1. Description of dataset and scripts
The dataset and script were developed to
1. Explore Darwin’s finch movement and space use ;
2. Ascertain data quantity and quality for a 3-week data collection period;
3. Identify limitations of radio-telemetry methods in a volcanic terrain.
To fulfil these aims, we deployed VHF radio-telemetry tags on a focal sample of five medium ground finches (Geospiza fortis) on Santa Cruz in the Galápagos, Ecuador. We then estimated the home range and core area of these birds in the arid coastal zone and characterized their habitat selection patterns and movement behaviour.
The scripts and data and for the R language (R Core Team 2022; R version, 4.0.4 (Lost Library Book)).
2. File List:
File 1
Description: Data to generate the main figures.
File 2
Name: Beausoleil_2022_Main.figures.R
Description: The main script generates the main figures.
Dependencies: requires "Beausoleil_2022_initialize.R" and "Beausoleil_2022_add_legend_to_empty_facet.R".
File 3
Name: Beausoleil_2022_initialize.R
Description: Load packages and custom functions for the analyses
Dependencies: Installation of the packages
File 4
Name: Beausoleil_2022_add_legend_to_empty_facet.R
Description: Function to plot legend in ggplot.


1. Number of variables:
See below.
2. Number of cases/rows:
See below.
3. Variable List:
- `elgar.hab` (6 rows):
- Polygon of habitat (sf object),
- geometry (a polygon or multipolygon) for the habitats, "Beach", "Inland water", "Manzanillo Forest", "Opuntia Forest", "Pacific Sea", and
"Road Paved".
- `data.birds` (143 rows):
- Locations of all birds (sf object with a data frame)
- pid (point ID)
- band (band number of each bird)
- PointType (the bird's activity: "Diurnal activity", "Nest", and "Roosting")
- date (of the observed point), and
- geometry (containing the coordinates of the points).
- `` (219 rows):
- Razimuth data.frame that was input in the model (raw data)
- indiv (number of each bird)
- obs_id (identification number for the point that was recorded)
- utm_x (x coordinate)
- utm_y (y coordinate)
- azimuth (in angle)
- date (of the observed point)
- PointType (the bird's activity: "Diurnal activity", "Nest", and "Roosting"),
- prior_r (prior for the model)
- `model.matrix` (116 rows):
Locations of the finches in data frame format estimated with the azimuthal telemetry model
- `model.output.list` (length 5):
List of the 5 MCMC models output (from razimuth package), one for each bird.
4. Missing data codes:
5. Abbreviations used:
6. Other relevant information:
Please refer to the article.


R Core Team. 2022. R: A language and environment for statistical computing. R Foundation for Statistical Computing. Vienna, Austria.


Please, refer to the article and the README.


Fonds de Recherche du Québec – Nature et Technologies