DOI: 10.5061/dryad.hdr7sqvww
title: Corticosterone-implanted chicks transmit stress to parents and neighbors in a colonial seabird

description: In animals living in groups, stress-induced changes in behavior can be a
 source of social information, and stressed individuals can potentially
 become stressors for other social partners, with important consequences
 for social and population dynamics. Here, we studied stress transmission
 from experimentally stressed chicks to both their parents and neighbors in
 the yellow-legged gull (Larus michahellis), a seabird that forms large
 breeding colonies. To do this, we experimentally increased the level of a
 stress hormone by corticosterone implant in the first-hatched chicks of
 the brood and observed its effects on their parents and both adults and
 chicks in the neighboring nests. Two days after the implant,
 corticosterone-implanted chicks showed reduced basal corticosterone
 levels, probably due to a physiological feedback response. Exogenous
 corticosterone promoted behavioral changes in the corticosterone-implanted
 chicks, showing faster responses to a potential predator attack than the
 placebo-treated chicks. Eight days after implantation, not only the
 corticosterone-implanted chicks but also the neighboring chicks showed
 elevated corticosterone levels after a standardized handling stress
 compared to the placebo-implanted chicks and their neighbors. The parents
 and neighbor adults of the corticosterone-implanted chicks showed
 increased mobbing behavior but reduced aggressive and resting behaviors in
 comparison to the adult gulls living close to the placebo-implanted
 chicks. Overall, our results suggest that individual physiological stress
 in a colony may be socially transmitted within families and neighbors,
 with potential consequences for colony dynamics.
description: # **Corticosterone-implanted chicks transmit stress to parents and
 neighbors in a colonial seabird** #### Journal: Behavioral Ecology ####
 Susana Cortés-Manzaneque, Sin-Yeon Kim, and Alberto
 Velando
Corresponding author:
 [avelando@uvigo.es](mailto:avelando@uvigo.es) #### About the Study In this
 study, we experimentally increased corticosterone levels in gull chicks
 and observed physiological and behavioral changes not only in the focal
 individuals but also in their parents, and neighboring adults, and chicks.
 **before_implant.csv** This data was used to test for any possible
 difference before implantation. **Description of variables used for data
 analysis:** * `broodID`: brood identifier * `dyadID`: nest dyad identifier
 * `dyad_treat`: nest dyad treatment (cort or placebo) * `brood_manipu`:
 brood type (implanted or neighbor) * `cort0`: plasma corticosterone level
 at implantation * `sex`: sex of the chick (F = female, M = male) *
 `eggvol`: egg volume (cm³) **2dpi.csv** This data was used to test the
 effect of corticosterone implants on corticosterone levels and behavior of
 the implanted chicks. **Description of variables used for data analysis:**
 * `dyad_treat`: nest dyad treatment (cort or placebo) * `sex`: sex of the
 chick (F = female, M = male) * `age2`: age of the chick at 2 days
 post-implantation * `cort0`: corticosterone level at implantation *
 `cort2`: corticosterone level 2 days post-implantation * `chatter`: number
 of chatter calls emitted * `tcrouch`: time to crouch * `(orq)tcrouch`:
 time to crouch (ORQ transformed) * `mass2`: body mass at 2 days
 post-implantation (g) The NAs indicate missing values for chicks that were
 excluded from the behavioral tests. **longitudinal.csv** This data was
 used to assess longitudinal variation in corticosterone levels and body
 development between 8 days post-implantation (8dpi) and fledging.
 **Description of variables used for data analysis:** * `broodID`: brood
 identifier * `dyadID`: nest dyad identifier * `dyad_treat`: nest dyad
 treatment (cort or placebo) * `brood_manipu`: brood type (implanted or
 neighbor) * `sex`: sex of the chick (F = female, M = male) * `sam_time`:
 sampling time (`8dpi` or `fledging`) * `age_imp`: age at implantation *
 `age`: age of the chick at sampling * `tarsus`: tarsus length (mm) *
 `cort0`: baseline corticosterone at 0 dpi * `cort`: baseline
 corticosterone at current sampling * `scort0`: square root-transformed
 baseline corticosterone at 0 dpi * `scort`: square root-transformed
 baseline corticosterone at current sampling **8dpi_stress_induced.csv**
 This data was used to test stress-induced corticosterone responses at
 8dpi. **Description of variables used for data analysis:** * `broodID`:
 brood identifier * `dyadID`: nest dyad identifier * `dyad_treat`: nest
 dyad treatment (cort or placebo) * `brood_manipu`: brood type (implanted
 or neighbor) * `sex`: sex of the chick (F = female, M = male) * `age`: age
 of the chick at sampling * `cort0`: baseline corticosterone at 0 dpi *
 `str_cort`: stress-induced corticosterone level * `(sqrt)cort0`: square
 root-transformed baseline corticosterone at 0 dpi * `(sqrt)str_cort`:
 square root-transformed stress-induced corticosterone level
 **moobing.csv** This data was used to quantify mobbing responses of adults
 in the colony during predator simulation trials. **Description of
 variables used for data analysis:** * `nest`: nest identifier * `dyadID`:
 nest dyad identifier * `dyad_treat`: dyad treatment (cort or placebo) *
 `brood_manipu`: brood type (implanted or neighbor) * `dives`: number of
 dive bombings * `s_calls`: number of squawking calls * `weather`: weather
 conditions during the trial (rainy or sunny) * `n_res`: number of
 researchers during the trial * `n_par`: number of parents present during
 the trial **adult_nest_behaviour.csv** This data was used to evaluate the
 behavior of adult gulls video recorded at the nest. **Description of
 variables used for data analysis:** * `nest`: nest identifier *
 `dyad_treat`: dyad treatment (cort or placebo) * `brood_manipu`: brood
 type (implanted or neighbor) * `dyadID`: nest dyad identifier *
 `time_day`: time of day when the video recording was made (1: morning, 2:
 afternoon) * `n_chicks`: number of chicks * `agres`: aggression frequency
 * `feed`: feeding behavior frequency * `rest`: resting behavior frequency
 * `groom`: grooming behavior frequency