Data from: Environmental conditions and individual characteristics influence movement patterns of juvenile Passerculus sandwichensis (Savannah sparrow) throughout the post-fledging period

Movements in the post-fledging period, an important first stage of natal
dispersal that occurs after juveniles fledge from the nest but before they
depart for fall migration, have important implications for survival.
However, relatively little is known about movements during this vulnerable
period. Here, we used daily radio telemetry data from 137 juvenile
Passerculus sandwichensis (Savannah sparrows) between 2022-2024 and
hierarchical generalized additive models to examine the relationship
between movement and age across a 90-day period. We evaluated how
movement—distance from the nest and between consecutive daily
locations—was influenced by age post-fledging, sex, brood number, year,
age at fledging, local nest density, nestling mass, and weather variables.
Both the distance of fledglings from their natal nest and distance moved
between days increased with age post-fledging, most steeply when
fledglings became independent, then remained steady for the remainder of
the post-fledging period. Movement varied among individuals: some
fledglings remained near the nest for extended periods and others traveled
long distances soon after fledging. Offspring from second broods traveled
greater distances than those from first broods. Nest density also
influenced movement, with fledglings from high density areas traveling
farther from their nests but, on average, less far between days. Movement
patterns were also influenced by year and sex, and weakly influenced by
mass and daily precipitation. Our results demonstrate how movement
patterns can change between the early post-fledging period and the
relatively understudied late post-fledging period.