DOI: 10.5061/dryad.xgxd254dp
title: Growing in the city: urban evolutionary ecology of avian growth rates.

description: Rapid environmental change driven by urbanisation offers a unique insight
 into the adaptive potential of wildlife as it can induce distinct
 selective pressures on urban dwelling organisms. Despite mounting evidence
 for urban-driven phenotypic differentiation across taxa, knowledge of the
 impact of urbanisation on vertebrate developmental rates and subsequent
 survival is very limited. Importantly, the role of selection on
 urban-driven body mass divergence in juvenile organisms remains poorly
 understood. We studied nestling development in a gradient of urbanisation
 set in Warsaw, Poland, in two nestbox breeding passerine species: great
 tits (Parus major) and blue tits (Cyanistes caeruleus). Each nestbox in
 the study system was assessed for surrounding percentage of Impervious
 Surface Area (ISA). Within these nestboxes, weight measurements of
 individual nestlings were collected during three breeding seasons and at
 regular intervals after hatching. Although asymptotic mass and growth rate
 were not directly affected by ISA in a subset of frequently measured
 nestlings, the age of fastest growth (inflection point) was delayed in
 blue tit nests surrounded by greater ISA. Across the entire dataset,
 nestling body mass was negatively affected by increasing ISA at days 5 and
 10 after hatching for great tits, and at days 10 and 15 for blue tits,
 respectively. Concomitantly, offspring survival at days 5 and 10 decreased
 with increasing ISA for both species. An analysis of selection
 differentials performed for two contrasting levels of imperviousness (low
 and high ISA) revealed a significant positive association between mass at
 day 2 and survival at fledging. Importantly, the strength of selection for
 heavier nestlings at hatching was greater for great tits in the more
 transformed, high ISA environment. This study confirms the considerable
 impact of imperviousness -a proxy for urbanisation level- on offspring
 development, body mass and survival, and highlights increased selection on
 avian birth weight in a high ISA environment.
description: MATERIALS AND METHODS 2.1  Study
 sites Data was collected for three field seasons
 between 2016 and 2018 in a gradient of urbanisation in the city of Warsaw,
 Poland. Five hundred Schwegler woodcrete nestboxes (type 1b with 32 mm
 entrance hole, suitable for great tits and blue tits) were erected in a 50
 m grid in eight contrasted study sites representative of the urban mosaic:
 six were located within the city borders while two were exurban sites
 (Figure 1). The total number of nestboxes within each area varied from 21
 to 110. While the monitoring of three sites (B, E and H) had already
 started in 2016, these and all other sites were monitored in 2017 and
 2018. 2.2  Quantifying urbanisation
 Urbanisation was quantified in a 100m radius around each nestbox
 in the study. This corresponds to literature-based estimates of parental
 foraging while chick feeding, assessed in blue tits to average 53.2 meters
 (±22.9 SD) in food poor (but natural) environments (Tremblay et al.,
 2004). In such food poor environments, birds were also reported to fly
 beyond 50 m from the nest in <i>c</i>. one-third of all
 foraging trips (Tremblay et al., 2004). An estimation of urbanisation in a
 100m radius around each nestbox thus corresponds to a conservative
 estimate of the range of food foraging distance covered by parents of
 offspring developing in the nest. Within this radius, we estimated the
 proportion of Impervious Surface Area (ISA) in QGIS following Szulkin et
 al. (2020). Specifically, a 20 m-pixel resolution of ISA extrapolated via
 satellite imagery from 2015 (Copernicus Land Monitoring Services, https://land.copernicus.eu/sitemap) was used to define ISA around each nestbox. Such index, expressed as a percentage, included all built-up areas that replaced original natural cover or water surfaces with an artificial and usually impervious surface. These artificial surfaces include built-up areas (such as infrastructural networks and buildings) and other elements characterised by a long cover duration. For further details on the imperviousness index description, see https://land.copernicus.eu/sitemap. 2.3  Life-history data collection and nestling measurements Starting from mid-March, nestboxes were inspected weekly to record the date of the first egg laid and clutch size. Hatching date was determined by visiting the nest one day before the expected hatching (12 days after the last egg of the clutch was laid) and around hatching date. Both laying and hatching dates were coded by setting the 1<sup>st</sup> of April as day 1. Only first broods, defined as broods that started no later than 30 days after the very first brood in a given year and site (Van Balen, 1973), were included in the analyses. Nestlings were uniquely marked by toenails clipping or by using waterproof markers on their first measurement day. In 2016, nestlings were individually weighed every 2 or 3 days from hatching (day 1) until ringing (day 15 or exceptionally, day 14 or 16, when the brood could not be accessed on day 15). In 2017 and 2018, nestlings were weighed specifically on days 2, 5, 10 and 15. Mass was recorded to the nearest 0.1 g using digital scales (KERN pocket balance CM 150-1N). At each nestbox visit, individual survival status (survived = 1, dead = 0) and brood size (number of chicks alive in the nest) were also recorded. In 2016, up to 50 µl blood samples were collected by puncturing the brachial vein of each 15 days old nestling. Blood samples were subsequently stored in 99.0% ethanol at +4° C until molecular sexing analysis. Finally, nestboxes were checked c. 25 days after hatching to determine fledging success for each individual nestling: individuals found dead in the nest and individuals that were not present in the nestbox had a fledging success of 0 and 1, respectively. 2.4  Extrapolating data on temperature at the nestbox level Weather data over the three-year period were provided by the Polish Institute of Meteorology and Water Management (IMGW-PIB). Average daily temperature data were computed from Warsaw Okecie and Legionowo weather stations; the nearest sampling points for the study locations situated within and outside the city borders, respectively. To estimate temperature experienced by growing nestlings at the nestbox level, average temperature was calculated at each nestbox across the specific periods of interest: for growth curve analyses, we used averaged temperature from day 1 to day 15 of nestling growth. For body mass and survival analyses, we used averaged temperature from day 1 to day 2, from day 2 to day 5, from day 5 to day 10, from day 10 to day 15, which corresponds to the intervals between mass measurements. Finally, for fledging success, we used averaged temperature from day 15 to day 25.
description: Data used for this publication include two main files:
 1) <b>GrowthParam2016_EvoApp2019_FlexParamCurve:</b>
 contains the data used to test the effect of ISA on great tits and blue
 tits growth curve parameters. Statistical methods are described in detail
 in Section 2.6.1.
 2) <b>Survival_EvoApp2016_2017_2018:</b> contains the
 data used to test the effect of ISA on great tit and blue tit nestling
 body mass (Section 2.6.2), survival (Section 2.6.3), and selection
 differentials (Section 2.6.4).  Additional files were
 used to generate figures in R (<em>ggplot</em>):
 3) <b>CurvePlot_EvoApp_Corsini2020:</b> data used to
 generate <b>Figure 2</b>.
 4) <b>selection_differential_coefficients_BT</b> and
 <b>selection_differential_coefficients_GT:</b><b> </b>combined data used to generate <b>Figure 3.</b>   <b>Legend and specific information on each dataset are listed below:</b>   dataset: GrowthParam2016_EvoApp2019_FlexParamCurve: Station ID climatic station, Waw = within Warsaw city borders, Leg = outside Warsaw city borders (PAL and KPN) NestboxID nestbox ID Ring Ring number DateGr Date expressed as dd/mm/yyyy JDateGr Julian date (1st of April as 1) Asym Asymptotic mass (in g) k growth rate Infl Inflaction point (in days) M shape of the curve Species GT= great tit, BT= blue tit Sex F= female, M= male HatN total number of hatched nestlings Fledged 1= fledged, 0 = not fledged CurveTest included for growth curve analyses, 1= yes, 0= no EDM earliest date of measurement (at which age - expressed in days - a nestling was measured for the first time) LayD when the first egg was laid (Julian date, 1st of April = 1) HatDJ when the first chick hatched in a brood (Julian date, 1st of April = 1) MeanT15 Mean temperature (in C) across the 15 or 16 days of each nestling growth ISA impervious surface area (expressed as a percentage) CS clutch size  D2 body mass (in g) at day 2 (hatching date =  day 1) D10 body mass (in g) at day 10 (hatching date =  day 1) D15 body mass (in g) at day 15 (hatching date =  day 1) D16 body mass (in g) at day 16 (hatching date =  day 1) Note: only one year of data (2016 - high resoluted measurements)   dataset: Survival_EvoApp2016_2017_2018: <b>Sheet: Nestlings_EvoApp2019</b> Year 2016, 2017, 2018   Site Study site abbreviation (8 sites) POL (urban park), KPN (National park - forest), UNI (Office area), MUR (Residential area I ), OLO (Residential area II), CMZ (Urban woodland I), LOL (Urban woodland II), PAL (Suburban village) Species BT: blue tit, GT: great tit   Sex_ch M: male, F: female nestling sex LayD Laying date (1st of April as 1) comment: Only first broods considered HatD Hatching date (1st of April as 1)   ChickID NestboxID_Ring unique id per single nestling CS Clutch size (Number of eggs)   d2 nestling mass at day 2 (in g) comment: hatching date taken as Day 1 d5 nestling mass at day 5 (in g) comment: hatching date taken as Day 1 d10 nestling mass at day 10 (in g) comment: hatching date taken as Day 1 d15 Nestling mass at day 15 (in g) comment: chicks were ringed at Day 15       sur2 1: survived, 0: not survived nestling survived between Day 0 and Day 2  sur5 1: survived, 0: not survived nestling survived between Day 2 and Day 5 sur10 1: survived, 0: not survived nestling survived between Day 5 and Day 10 sur15 1: survived, 0: not survived nestling survived between Day 10 and Day 15 Fledged 1: fledged; 0:not fledged to infer fledging success, nests were checked 25 days after hatching (D25). Hatching date taken as D1. Nestlings survived between Day 15 and Fledging (day 25) ISA Impervious surface in % Comment: built up area in % (buldings, paved roads, etc), calculated on 100m radius at the nestbox level. TIFF file obtained from Copernicus. Note: missing data = NA         sur2old 1: survived, 0: not survived nestling survived until Day 2  sur5old 1: survived, 0: not survived nestling survived until Day 5 sur10old 1: survived, 0: not survived nestling survived until Day 10 sur15old 1: survived, 0: not survived nestling survived until Day 15 Fledgedold 1: fledged; 0:not fledged to infer fledging success, nests were checked 25 days after hatching (D25). Hatching date taken as D1. broodID unique brood ID unique brood ID created specifying Year_NestboxID <b>Sheet: Broods_EvoApp2019</b> Year 2016, 2017, 2018   Site Study site abbreviation (8 sites) POL (urban park), KPN (National park - forest), UNI (Office area), MUR (Residential area I ), OLO (Residential area II), CMZ (Urban woodland I), LOL (Urban woodland II), PAL (Suburban village) Species BT: blue tit, GT: great tit   CS Clutch size (Number of eggs)   HatD Hatching date (1st of April as 1)   HatN Total number of hatched nestlings         Nr_D2 Number of alive nestlings at day 2   Nr_D5 number of alive nestlings at day 5   Nr_D10 number of alive nestlings at day 10   Nr_D15 number of alive nestlings at day 15   Nr_Fledged total number of fledged chicks   ISA Impervious surface in % Comment: built up area in % (buldings, paved roads, etc), calculated on 100m radius at the nestbox level. TIFF file obtained from Copernicus. BroodID_unique unique brood ID unique brood ID created specifying  NestboxID, Species and Year Note: empty cells are missing data Daily temperature (in C) (from 2 meteorological stations: Warsaw and Legionowo. Legionowo data used for KPN and PAL). T1_2 averaged daily temp between day 1 and day 2 (included) for body mass and survival at day 2  T2_5 averaged daily temp between day 2 and day 5 (included) for body mass and survival at day 5 T5_10 averaged daily temp between day 5 and day 10 (included) for body mass and survival at day 10 T10_15 averaged daily temp between day 10 and day 15 (included) for body mass and survival at day 15 T15_25 averaged daily temp between day 15 and day 25 (included) for survival at fledging T1_25 averaged daily temp between day 1 and day 25 (included) for selection analyses Station: Climatic station (Waw = within Warsaw city borders, Leg = outside Warsaw city borders, KPN and PAL)   dataset: CurvePlot_EvoApp_Corsini2020 <b>Sheet: Data</b> NestboxID Nestbox id. Species GT= great tit, BT = blue tit. Day brood age expressed in days (hatching date = day 1). BrMass Mass average at the brood level (in g). ISA Impervious Surface Area (in %). newISAcat ISA category (as low or high). Note: the plot shows growth inferred at the brood level for 1 year of data (2016) and across 3 study sites (POL, CMZ and KPN).