Data from: How far can frugivorous birds disperse seeds during migration?
Data files
Sep 30, 2025 version files 174.03 KB
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departure_times.csv
2.64 KB
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flight_distances.csv
1.68 KB
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flight_speeds.csv
16.05 KB
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ingestion_times.csv
2.16 KB
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README.md
5.78 KB
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seed_retention_times.csv
145.72 KB
Abstract
Long-distance seed dispersal plays a crucial role in shaping plant distributions. The annual migration of millions of frugivorous birds holds substantial potential for the long-distance dispersal of fleshy-fruited plants, which are a major component of forests and woodlands globally. However, quantitative estimations of seed-dispersal distances mediated by migrant frugivorous birds are still lacking. Here, we uniquely combine GPS-tracked movement data of thrushes migrating across Europe (n = 38 individuals) with empirical data on fruit consumption, flight departure and speed, and seed retention times in the birds’ gut to mechanistically simulate dispersal events. Our results reveal that, during migratory flights, frugivorous birds can disperse seeds over tens to hundreds of kilometres, depending on the plant species (range across species: mean = 9–45 km; P99.9 = 42–221 km; max. = 58–521 km). In contrast, most dispersal distances (P99.9) by non-migratory movements were within 1 km. Smaller-seeded species disperse farther due to their longer seed retention times. Our study fills an important knowledge gap on the large-scale dispersal of fleshy-fruited plants by migratory birds and uncovers interspecific, trait-based differences in their long-distance dispersal capacity.
Dataset DOI: 10.5061/dryad.bnzs7h4pw
Description of the data and file structure
This repository contains the input data used to run and compare mechanistic models predicting seed dispersal distances of 31 fleshy-fruited plant species generated by migratory frugivorous birds. We focused on song thrushes (Turdus philomelos) as the study migratory bird, one of the most important frugivorous birds in Europe. The project integrates both Bayesian parametric and non-parametric approaches, relying on empirical and literature-derived data.
Files and variables
Datasets:
1."departure_times.csv"
2."flight_distances.csv"
3."flight_speeds.csv"
4."ingestion_times.csv"
5."seed_retention_times.csv"
Description of the data and file structure
1."departure_times.csv"
Raw data on migratory flight departure times of the ring ouzel (Turdus torquatus), a nocturnal migratory bird that is closely related to the song thrush. Departure times were recorded using high-precision geolocators and are expressed in minutes relative to sunset, with negative values indicating departures occurring before sunset. This work was conducted by the division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, Bern, and by the Swiss Ornithological Institute, Sempach, (Switzerland). The data were obtained after request from Barras et al. (2021, https://doi.org/10.1111/jav.02860).
Variables:
-"departure_time": time of initiation of migratory flights, expressed in minutes relative to sunset.
2."flight_distances.csv"
Raw data on migratory flight distances of song thrushes (between stopovers), expressed in kilometres. Data were obtained from GPS-tagged song thrushes migrating through the European continent (see details in the Main text). Between 2019 and 2023, a total of 55 song thrushes were captured, ringed and GPS-tagged with PinPoint GPS-Argos P75 tags. This work was conducted in southern Spain, to track the spring migration (n = 34 tagged in early March), and in ornithological stations located at the North Sea (Helgoland Inselstation in Germany) and at the Baltic Sea (Falsterbo Fågelstation in Sweden and Ventės Ragas in Lithuania) to track the autumn migration (n = 21 tagged in early October). This work was conducted by the Departamento de Biología, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz (Spain). The data were extracted from González-Varo et al. (2025, unpublished).
Variables:
-"flight_distance": distance of migratory flights between stopovers, expressed in kilometres.
3."flight_speeds.csv"
Raw data on migratory flight airspeeds of song thrushes, expressed in kilometres per minute. Data were collected on the Courish Spit of the Baltic Sea using an optical-electronic matrix system, designed to study the movements of nocturnal migratory birds. This work was conducted by the Biological Station “Rybachy”, Zoological Institute of the RAS, Rybachy, 238535, Kaliningrad region (Russia). The data were obtained after request from Sinelschikova et al. (2020, https://doi.org/10.1016/j.beproc.2020.104154).
Variables:
-"flight_speed": airspeed of migratory flights between stopovers, expressed in kilometres per minute.
4."ingestion_times.csv"
Raw data on fruit ingestion times by song thrushes, expressed in minutes relative to sunset. Negative values indicate departures occurring before sunset. Data were collected on the Doñana National Park (southern Spain) from 2018 to 2023 (four complete fruiting seasons), using 70 camera traps to record pairwise plant-animal frugivory interactions. This work was conducted by the Estación Biologica de Doñana, CSIC, Seville (Spain). This included information on the frequency and timing of frugivore visits to individual plants. The data were extracted from Villalva et al. (2024, https://doi.org/10.1002/ecy.4424).
Variables:
-"ingestion_time": ingestion time of fruits by song thrushes, expressed in minutes relative to sunset.
5."seed_retention_times.csv"
Raw data on seed retention times in the digestive tract of song thrushes, expressed in minutes. Data were collected from a set of seed retention time experiments using frugivorous birds that ingested fruits of fleshy-fruited plants, using digital video cameras to record the minute of ingestion and the minute of ejection of seeds. This is reported for the target plant species included in the seed dispersal mechanistic models. This work was conducted by the Departamento de Biología, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, at the Centro de Conservación de la Biodiversidad ZooBotánico Jerez—Alberto Durán, Cádiz (Spain). The data were extracted from Bracho-Estévanez et al. (2024, https://doi.org/10.1111/1365-2435.14642).
Variables:
-"plant_sp": plant species names.
-"seed_retention_time": seed retention time in the digestive tract of song thrushes (minutes).
Code/software
R project and code to reproduce the data analyses is available at figshare (link at the Data Availability Statement of the study).
The code consists of the following files:
0.Load_libraries.R
1.Workflow_mechanistic_models.R
2.Results_mechanistic_models.R
3.Comparison_mechanistic_models.R
4.Folder with five .stan codes corresponding to the fit of specific statistical distributions to each input variable.
All analyses were conducted in the R using the software versions listed below.
R version 4.2.3 (2023-03-15 ucrt) -- "Shortstop Beagle"