Breeding site departure and post-departure movement strategy in Vireo olivaceus (Red-eyed Vireo)

Few studies have been able to assess the decision-making process behind migratory departures from the breeding site and the extent to which extrinsic cues that favor departure from fall stopover sites also apply to initial departure from breeding sites. Factors influencing departure may vary between species that first make short-distance regional movements vs. those that immediately begin long-distance migration, but for most migratory songbirds, it is unknown which post-departure movement strategy they use or why. We used an automated radio telemetry network to track adult male Vireo olivaceus (Red-eyed Vireo) as they departed their northwest Pennsylvania breeding site on fall migration to determine their post-departure movement strategy. We also assessed how local weather conditions, including surface pressure, humidity, precipitation, and wind, influenced the probability of departing the breeding site on fall migration. For the individuals for whom we could confidently ascertain depa..., , # Breeding site departure and post-departure movement strategy in *Vireo olivaceus* (Red-eyed Vireo)

Dataset DOI: [10.5061/dryad.8sf7m0d27](10.5061/dryad.8sf7m0d27)

## Description of the data and file structure

Weather variables influencing migratory departure decisions for 22 Red-eyed Vireos.

### Files and variables

#### File: Horn_et_al_2025_data.csv

**Description:** Dataset for Cox proportional hazards models to assess how weather variables influence the probability of birds departing the breeding site on fall migration. 

##### Variables

* ID: tag number for each bird
* status: 0= did not depart, 1=departed
* year: 2020 or 2021
* detect.date: dates during the migratory period that each bird did not depart, up until their actual departure date
* detect.time: time of migratory departure
* start.time: start time for Cox model calculation
* end.time: end time for Cox model calculation
* depart.day.of.year: day of year that each individual departed on migration
* surface.pressure....,