DOI: 10.5061/dryad.bnzs7h4pw
title: Data from: How far can frugivorous birds disperse seeds during migration?

description: 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.
description: # Data from: How far can frugivorous birds disperse seeds during
 migration? Dataset DOI: [10.5061/dryad.bnzs7h4pw](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](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](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](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](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"