DOI: 10.5061/dryad.ffbg79d7m
title: Data from: Chicks of cavity-nesting birds do not ‘exercise’ prior to fledging

description: Fledging represents a key life-history transition involving a rapid
 increase in workload associated with a rapid transition from sedentary
 nestling to volant, active fledgling. Here, we tested the idea that chicks
 might prepare for fledging through increased voluntary activity
 (‘exercise’) and whether this would impact somatic and physiological
 development. European starling (Sturnus vulgaris) chicks, in cavity nests,
 increased levels of putative exercise (wing flapping) and more general
 active behaviours (e.g., perching, standing) in the five days up to
 fledging. However, facultative mass loss and wing growth between days 15 –
 20 were independent of time spent wing flapping, standing, or perching,
 and – counterintuitively – we found a weak negative relationship between
 hematocrit (a measure of aerobic capacity) and time spent wing flapping or
 standing. Thus, although exercise is commonly associated with an increase
 in hematocrit in other species, this does not appear to be a mechanism for
 increasing pre-fledging hematocrit in chicks. Despite widespread anecdotal
 observations of flight preparation (e.g., wing flapping) in larger
 seabirds and raptors, our data suggest that exercise, or increased
 activity in general, does not contribute to improved development just
 prior to fledging: starling chicks do not ‘exercise’ enough to show
 somatic or physiological effects.
description: # Data from: Chicks of cavity-nesting birds do not ‘exercise’ prior to
 fledging Dataset DOI:
 [10.5061/dryad.ffbg79d7m](https://doi.org/10.5061/dryad.ffbg79d7m) ##
 Description of the data and file structure **Chicks of cavity-nesting
 birds do not ‘exercise’ prior to fledging** Kate Earle ^1,2^, Josh Allen
 ^1,2^, Brett Hodinka ^1^, and Tony D Williams ^1^ **Note:** Within
 spreadsheets, "." values indicate either missing data (e.g.,
 when chicks fledged early, before day 20, so day 20 blood samples and
 measurements could not be obtained, indicated by “earlyf” column) or b)
 where data were not collected in all years, e.g. behavioural data on
 maintenance, perching, sitting, standing and walking were only collected
 in 2023. These missing data are detailed for specific variables below: **R
 code and data files** A1) Activity_2021_22_220925_revision.R – R code for
 analysis of activity*chick age using 2021/22 data A2)
 Activity_2021_22_220925_revision.csv – data for Activity 2021_22 analysis
   year                       Year of data collection box       
                 Nest box number chickid                Chick ID age       
                 Chick age (days) extdur                  Duration of wing
 extensions (sec) extbout                 Number of wing extension bouts
 flapdur                 Duration of wing flapping (sec)
 flapbout              Number of wing flapping bouts totdur  
                 Total duration of activity recording (min)
 extdur60             Duration of wing extensions (sec) corrected to 60 min
 extbout60          Number of wing extension bouts corrected to 60 min
 flapdur60            Duration of wing flapping (sec) corrected to 60 min
 flapbout60         Number of wing flapping bouts corrected to 60 min   A3)
 Activity_2023_220925_revision.R - R code for analysis of activity*chick
 age using 2023 data A4) Activity_2023_220925_revision.csv – data for
 Activity_2023 analysis   date                      Date (day/mon/year)
 time                      Time of day (hours:min) viddur                  
 Duration of activity recording (hours:min:sec) decdur                
 Duration of activity recording as decimal box                        Nest
 box number chickid                 Chick ID boxchick             Combined
 code for box and chick age                        Chick age (days)
 state                     Type of activity: FL = flapping, M =
 maintenance, P = perching, SI = sitting, ST =                             
                 standing, WA = walking statest                 Start of
 activity stateen                End of activity timesp                
 Time spent in activity (sec) statdur                 Time spent in
 activity (sec) as decimal act                         Active or inactive
 behaviour (as described in MS) bs                           Brood size or
 number of chicks hct                         Hematocrit (PCV, %) – data
 missing for chicks that fledged early hb          
                Hemoglobin (g.dl ^-1^ whole blood) – data missing for
 chicks that fledged early   adjdur                  Duration of activity
 (sec) corrected to 60 min   A5) Pooled_development_220925_revision.R – R
 code for analysis of year differences in mass loss and wing growth,
 activity with brood size and metrics or somatic and physiological
 development, pooling all years (where possible) A6)
 Pooled_development_220925_revision.csv – data for pooled development
 analysis   year                       Year of data collection box       
                 Nest box number chickid                 Chick ID
 bs                           Brood size or number of chicks
 obsnum               Number of observations obsdur                
 Duration of observations earlyf                    Did chick fledge early
 (Y/N): some subsequent data NA if “Y” ht15                      Handling
 time: time from capture to blood sampling, day 15 (min) ht20     
                 Handling time: time from capture to blood sampling, day 20
 (min) mass15               Body mass (g) day 15 wing15                
 Wing length (mm) day 15 tars15                  Tarsus length (mm) day 15
 mass20               Body mass (g) day 20 wing20                 Wing
 length (mm) day 20 tars20                  Tarsus length (mm) day 20
 hct                         Hematocrit (PCV, %) – data for 2023 and
 “earlyf = N” only hb                          Hemoglobin (g.dl ^-1^ whole
 blood) – data for 2023 and “earlyf = N” only dmass                  Change
 in body mass (g) between days 15 and 20 dwing                   Change in
 wing length (mm) between days 15 and 20 xflapdur               Mean
 duration wing flapping (sec) xflapbout            Mean number of flapping
 bouts – 2021/22 only xextdur                 Mean duration of wing
 extensions (sec) = 2021/22 only xextbout              Mean number of wing
 extension bouts – 2021/22 only xmaintain          Mean duration,
 maintenance (sec) – 2023 only xperch                 Mean duration,
 perching (sec) – 2023 only xsit                         Mean duration,
 sitting (sec) – 2023 only xstand                  Mean duration, standing
 (sec) – 2023 only xwalk                    Mean duration, walking (sec) –
 2023 only 20flap                   Time spent flapping (sec), day 20 only
 20perch              Time spent perching (sec), day 20 only who      
                 Who led data collection xage                      Mean age
 for days with activity recording cumage               Cumulative age for
 activity recording, e.g. if activity was recorded at ages 16, 17 and
                                 18, then cumulative age = 51