10.5061/DRYAD.QG630
Madliger, Christine L.
University of Windsor
Love, Oliver P.
University of Windsor
Data from: Do baseline glucocorticoids simultaneously represent fitness
and environmental quality in a declining aerial insectivore?
Dryad
dataset
2016
glucocorticoid
provisioning rate
Tachycineta bicolor
habitat quality
Tree swallow
feather clipping
inter-annual
2016-04-22T16:48:08Z
2016-04-22T16:48:08Z
en
https://doi.org/10.1111/oik.03354
13433 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Glucocorticoids (GCs) are often interpreted as indicators of disturbance,
habitat quality, and fitness in wild populations. However, since most
investigations have been unable to examine habitat variability, GC levels,
and fitness simultaneously, such interpretations remain largely
unvalidated. We combined a quantification of two habitat types, a
manipulation of foraging ability (feather-clipping just prior to nestling
rearing), multiple baseline plasma GC measures, and multi-year
reproductive monitoring to experimentally examine the linkages between
habitat quality, GCs, and fitness in female tree swallows Tachycineta
bicolor. Control females experiencing the higher early-season food
resources of inland–pasture habitat laid larger clutches, but fledged an
equal number but lower mass offspring compared to those in
riparian–cropland habitat. Despite these differences in reproductive
success, females nesting in the two habitat types did not differ in
baseline GC levels at the early- or late-breeding stage. Feather-clipping
reduced provisioning rate in both habitat types. However, baseline GC
levels were affected in a habitat-specific way; only individuals in
inland–pasture habitats showed an increase in GCs. Despite this difference
in GC levels, the manipulation did not influence offspring mass,
reproductive output, adult return rate (a proxy for survival) to the
following year, or reproductive success in the subsequent year.
Nonetheless, regardless of treatment, individuals with higher GC levels
during the late breeding stage returned in the following year with higher
GC levels at incubation, indicating a long-term effect on future GC
levels. Our results indicate that environmental changes (e.g. foraging
conditions) can have consequences for body condition, behaviour, and
current and future baseline GC levels without concomitant influences on
fitness, and that differences in fitness components between habitats may
not be reflected in baseline GC levels. These results illustrate that
baseline GCs may not simultaneously reflect environmental quality and
fitness, potentially limiting their application in ecological and
conservation settings.
Madliger Love_Oikos 2016_Insect biomass by habitatDaily flying insect
biomass (g) by month by habitat type (Riparian Cropland and Inland
Pasture)Madliger Love_Oikos 2016_Within-year manipulation
effectsCorticosterone levels, provisioning rates, and fitness metrics of
control and feather-clipped female tree swallows across two habitat types
(Riparian Cropland and Inland Pasture)Madliger Love_Oikos
2016_Inter-annualFuture investment, fitness, and corticosterone levels of
control and feather clipped female tree swallows across two habitat types
(Riparian Cropland and Inland Pasture)