DOI: 10.5061/dryad.r4xgxd28n
title: Contrasting sensitivity of nestling and fledgling Barn Swallow Hirundo rustica body mass to local weather conditions

description: Local weather can influence the growth and development of young birds,
 either indirectly, by modifying prey availability, or directly, by
 affecting energetic trade‐offs. Such effects can have lasting implications
 for life history traits, but the nature of these effects may vary with the
 developmental stage of the birds, and over timescales from days to weeks.
 We examined the interactive effects of temperature, rainfall and wind
 speed on the mass of nestling and fledgling Barn Swallows Hirundo
 rustica, both on the day of capture and averaging weather across the time
 since hatching. At the daily timescale, nestling mass was negatively
 correlated with temperature, but the strength of this association depended
 on the level of rainfall and wind speed; nestlings were typically heavier
 on dry or windy days, and the negative effect of temperature was strongest
 under calm or wet conditions. At the early lifetime timescale (i.e. from
 hatching to post‐fledging), nestling mass was negatively correlated with
 temperature at low wind speed. Fledgling body mass was less sensitive to
 weather; the only weather effects evident were a negative correlation with
 temperature at the daily scale under high rainfall that became slightly
 positive under low rainfall. These changes are consistent with weather
 effects on availability and distribution of insects within the landscape
 (e.g. causing high concentrations of flying insects), and with the effects
 of weather variation on nest microclimate. These results together
 demonstrate the impacts of weather on chick growth, over immediate (daily)
 and longer term (nestling/fledgling lifetime) timescales. This shows that
 sensitivity to local weather conditions varies across the early lifetime
 of young birds (nestling‐fledgling stages) and illustrates the mechanisms
 by which larger scale (climate) variations influence the body condition of
 individuals.
description: <strong>For details of colleciton see Facey et al.
 2020 https://doi.org/10.1111/ibi.12824</strong> Headings "Female" and "Chick" (here referring to both nestling and fledgling, see under “Groups) refer to identities of individuals derived from ring/band numbers. Chick = 8-12 days old Fledgling = 20+ days Attempt – <em>breeding attempt, second breeding attempt was considered to be any breeding attempt by the same female that followed a successful first breeding attempt.</em> Brood Size – <em>maximum number of chicks recorded in the nest</em> Age – <em>hatching to “Day”</em> Time – <em>hour during which individuals was handled/weighed (24 hour clock)</em> Day – <em>day of handling/weighed, where day 1 = 1<sup>st</sup> April</em> Mass – <em>weighed to the nearest 0.1 g using an electronic balance </em>(Satrue SA-500 http://www.satrue.com.tw/dp2.htm)<em>.</em> <strong>Weather data</strong> <em>see</em> Facey et al. 2020  https://doi.org/10.1111/ibi.12824 for details on the origins and handling of weather data. Temperature (<em><sup>o</sup>C) - mean of the daily maximum and daily minimum values </em> Wind speed (km/h)<em> – daily mean</em> Rainfall (mm)<em> – total of daily totals. </em>
description: These data related to the age and mass (see below) of 248
 nestling (8–12 days old) Barn Swallows <em>Hirundo
 rustica</em>, and 75 fledglings (20+ days),  and the weather
 conditions on the day of handling and over their lifetime.
 Data needs to be run as two subsets of “Chicks” and “Fledglings”
 (see under “Group” heading)   The dataset contains no
 missing values.