Age-related differences in fall migration timing and performance of juvenile and adult Wood Thrushes departing from a breeding site

Juvenile passerines are expected to have lower migration performance than adults due to their inexperience with long-distance flights and morphological limitations, such as shorter wing length. From 2016-2019 we radio-tagged nestling and adult Wood Thrushes (Hylocichla mustelina) at a breeding site in southwestern Ontario and used the automated Motus Wildlife Tracking System to test if age class predicts timing of the onset of fall migration (date, time of night), flight speed during the initial migration flight across Lake Erie, and overall pace of migration southward through the eastern United States. We detected 60/117 (51%) adults and 82/119 (69%) juveniles departing the breeding area as they initiated fall migration. Compared with adults, juveniles departed significantly earlier in fall and significantly later in the evening. When crossing Lake Erie on their first migration flight juveniles travelled about 25% slower than adults but this was due primarily to adults making better us..., Radio-tagging
When nestlings were 10 days old, shortly before fledging which occurs at 12-14 days, they were removed from the nest and banded with both Canadian Wildlife Service numbered aluminum bands and unique color band combinations. The largest nestling (by mass) had a blood sample (<25 uL) taken for genetic sexing (HealthGene Molecular Diagnostic and Research Center, Concord, Canada) and was equipped with a uniquely coded radio transmitter using a backpack leg loop harness (Rappole and Tipton 1991) made from 2.5mm Teflon tubing. Only one nestling was tagged at most nests (82%; 131 of 160 nests) but two nestlings were tagged at 29 nests that fledged late in the season. Of all tagged nestlings (n = 189), 133 survived to 16 days post-fledging and 119 survived to the onset of fall migration. We refer to this age class as juvenile.
Adults were caught by placing mist nets in the vicinity of nests and then banded with both Canadian Wildlife Service numbered aluminum bands and unique c..., , # Age-related differences in fall migration timing and performance of juvenile and adult Wood Thrushes departing from a breeding site

[https://doi.org/10.5061/dryad.r7sqv9snq](https://doi.org/10.5061/dryad.r7sqv9snq)

## Description of the data and file structure

This data was collected during the summers of 2016-2019 in Norfolk County, Ontario, Canada. Wood Thrushes were captured in a variety of forest fragments and tagged using coded Nanotags designed to work with the automated telemetry Motus Wildlife Tracking System. To attach tags to birds, adult Wood Thrushes were captured in mist nets and juvenile Wood Thrushes were briefly removed from the nest at 10 days old, shortly before fledging. We used the time and location of detections recorded by the Motus system to populate the spreadsheets in this dataset. The data have been uploaded in three separate spreadsheets and the title of each spreadsheet identifies the analysis that it was used for.

### Files and variables

#### File: Bo...,