DOI: 10.5061/dryad.bvq83bkk9
title: Long-term increases in wing length occur independently of changes in climate and climate-driven shifts in body size

description: Recent widespread reductions in body size across species have been linked
 to increasing temperatures; simultaneous increases in wing length relative
 to body size have been broadly observed, but remain unexplained. Size and
 shape may change independently of one another, or these morphological
 shifts may be linked, with body size mediating or directly driving the
 degree to which shape changes. Using hierarchical Bayesian models and a
 morphological time series of 27,366 specimens from five North American
 migratory passerine bird species, we tested the roles that climate and
 body size have played in shifting wing length allometry over four decades.
 We found that colder temperatures and reduced precipitation during the
 first year of life were associated with increases in wing length relative
 to body size, but did not explain long-term increases in wing length. We
 found no conclusive evidence that the slope of the relationship between
 body size and wing length changed among adult birds in response to any
 climatic variable or through time, suggesting that body size is not
 mediating shifts in relative wing length. Together, these findings suggest
 that long-term increases in wing length are not a compensatory adaptation
 mediated by size reductions, but rather are driven by non-climatic
 factors.
description: Morphological data were collected from museum specimens located
 at the Field Museum. Environmental data were sourced
 from NOAA PSL. The datasets accessed included CPC global unified
 temperature data (daily), CPC global unified gauge-based precipitation
 data (daily), NASA GISS surface temperature data (monthly), and GPCP
 precipitation data (monthly). Data were cropped and aggregated according
 to species and season for each year. Data were also transformed within
 species to have a mean of 0 and a standard deviation of 1.
 Additional details are provided in the methods section of the
 manuscript.
description: # Long-term increases in wing length occur independently of changes in
 climate and climate-driven shifts in body size
 [https://doi.org/10.5061/dryad.bvq83bkk9](https://doi.org/10.5061/dryad.bvq83bkk9) ## Description of the data and file structure This dataset contains the data and code required to perform the main and supplementary analyses in **Long-term increases in wing length occur independently of changes in climate and climate-driven shifts in body size** (Dias et al. 2024. *Proc. Royal Soc. B.* [https://doi.org/10.1098/rspb.2024.2556](https://doi.org/10.1098/rspb.2024.2556)). The paper tests whether body size and climate drive allometric shifts in wing length across five North American migratory passerine bird species. ### Files and variables #### File: Data.zip **Description:** Contains two folders: Datasets and Files A. **Datasets** (4 .csv files) A1. **morphdata.csv** - contains all the morphological data used in the study [note: some of these specimens were filtered out prior to analysis (filtering steps included in code)]; for more detail refer to "Morphological data" subsection of the "Methods" section * "Taxon": species the specimen belongs to ("Junco_hyemalis", "Melospiza_georgiana", "Melospiza_melodia", "Seiurus_aurocapilla", "Zonotrichia_albicollis") * "Sex": sex of the specimen ("m" = male; "f" = female) * "NewAge": age class of the specimen ("HY" = hatch-year; "AHY" = after hatch-year) * "Year": year that the specimen was collected (1981-2016) * "Season": season that the specimen was collected (either "Spring" or "Fall") * "Tarsus": tarsus length (unit: mm) * "Wing": wing length (unit: mm) * "size_idx": size index (not used in analyses) * "wing_idx": wing index (not used in analyses) A2-4. **ed_FHY.csv**, **ed_AHYspring.csv**, **ed_AHYfall.csv** - contain environmental data for hatch-year, Spring after hatch-year, and Fall after hatch-year birds, respectively, that were produced by aggregating daily temperature data ([https://psl.noaa.gov/data/gridded/data.cpc.globaltemp.html](https://psl.noaa.gov/data/gridded/data.cpc.globaltemp.html)) and precipitation data ([https://psl.noaa.gov/data/gridded/data.cpc.globalprecip.html](https://psl.noaa.gov/data/gridded/data.cpc.globalprecip.html)) over a specific timespan (as specified in the paper) for the appropriate species' range, year, and season for pre-breeding, spring migration, and fall migration periods; contains environmental data from NOAA PSL that were reported monthly (temperature data - [https://psl.noaa.gov/data/gridded/data.gistemp.html](https://psl.noaa.gov/data/gridded/data.gistemp.html); precipitation data - [https://psl.noaa.gov/data/gridded/data.gpcp.html](https://psl.noaa.gov/data/gridded/data.gpcp.html)) and aggregated for the given species' range, year, and season for breeding and wintering seasons.; for more detail refer to "Climate data" subsection of the "Methods" section * "y_id": year ID for the row of environmental data in the remaining columns (see "Year") * "Species2", "spec_id": species ID for the row of environmental data in remaining columns ("Junco_hyemalis", "Melospiza_georgiana", "Melospiza_melodia", "Seiurus_aurocapilla", "Zonotrichia_albicollis") * "Year": only present in the ed_AHYspring.csv dataset; indicates the year in which specimens were collected (for AHY fall and HY specimens, "y_id" = "Year"; for AHY spring specimens, "y_id" = "Year" + 1; range: 1981-2016) * In the remaining columns (containing environmental data - each variable scaled to have a mean of 0 and a standard deviation of 1 within each species): * "Temp", "Precip" in the variable name = indicates whether a variable contains temperature data or precipitation data, respectively "MinTemp", "MaxTemp", "AvgTemp" in the variable name = indicates whether a temperature variable is the mean daily minimum temperature, mean daily maximum temperature, or mean daily average between max and min temperature * "SpringMig", "FallMig", "PreBreed", "Breed", "Win" = indicates which season (spring migration, fall migration, pre-breeding period, breeding season, and wintering season, respectively) the environmental variable contains data for * "Prev", "Next" = indicates whether the environmental variable contains data for that season in the previous year ("Prev" year = "y_id" - 1) or in the following year ("Next" year = "y_id" + 1) * "Mo" = indicates that the environmental variable contains monthly data * "Base", "B1", "B2", "S1", "S2", "S3" = indicate the degree to which the range was cropped (for breeding and pre-breeding variables) before calculating environmental variables for use in a range cropping sensitivity analysis; "Base" is the cropping used for our main models (included in green in Figure S1 in the Electronic Supplementary Material), "B1" is less restrictive cropping than "Base" (includes blue range in Figure S1), "B2" is the least restrictive cropping (includes purple range in Figure S1). "S1", "S2", and "S3" represent more restrictively cropped ranges that ultimately weren't used in our sensitivity analysis. B. **Files** (2 files) B1. **chitree.rds** - phylogenetic tree used in supplementary analyses B2. **catnodata.csv** - contains available catalog numbers and data for specimens used in the main and/or supplementary analyses * "Taxon": species the specimen belongs to ("Junco_hyemalis", "Melospiza_georgiana", "Melospiza_melodia", "Seiurus_aurocapilla", "Zonotrichia_albicollis") * "Sex": sex of the specimen ("m" = male; "f" = female) * "Age": age class of the specimen ("HY" = hatch-year; "AHY" = after hatch-year) * "Year": year that the specimen was collected (1981-2016) * "Season": season that the specimen was collected (either "Spring" or "Fall") * "CatNo": catalog number associated with the specimen * "InstCode": institution code for the associated specimen ("FMNH" = Field Museum of Natural History) ## Code/software #### File: Code.zip Code (3 files) 1\. **Script01_MainAnalyses.R** - R script (run using R version 4.3.0) that produces all results reported in the main manuscript (Tables 1-3) as well as some results reported in the electronic supplementary materials (Tables S1-S3); refer to comments in code for further detail 2\. **Script02_SupplementAnalyses.R** - R script (run using R version 4.3.0) that produces the remaining results reported in the electronic supplementary materials (Tables S4-S11); refer to comments in code for further detail 3\. **lm_mod.stan** - Stan file necessary to run the allometry models as described in the main manuscript (implemented using the rstan package); comments in code provide detail on model structure R packages required to run the code are included at the top of each script. Packages that aren't already installed, can be installed using R with the `install.packages()`. ## Access information Raw, non-aggregated environmental data is available through NOAA PSL: * Daily temperature data: [https://psl.noaa.gov/data/gridded/data.cpc.globaltemp.html](https://psl.noaa.gov/data/gridded/data.cpc.globaltemp.html) * Daily precipitation data: [https://psl.noaa.gov/data/gridded/data.cpc.globalprecip.html](https://psl.noaa.gov/data/gridded/data.cpc.globalprecip.html) * Monthly temperature data: [https://psl.noaa.gov/data/gridded/data.gistemp.html](https://psl.noaa.gov/data/gridded/data.gistemp.html) * Monthly precipitation data: [https://psl.noaa.gov/data/gridded/data.gpcp.html](https://psl.noaa.gov/data/gridded/data.gpcp.html) Our data came from: * The Field Museum (specimen/morphological data) * NOAA PSL (environmental data - cropped and aggregated for use in our study) * BirdLife International (species' range maps - used for cropping the environmental data obtained from NOAA PSL; not included here) * Our consensus phylogeny was generated using the global phylogeny of birds from doi:10.1038/nature11631, using the phylogeny constructed with the Hackett backbone tree, following the methods described in doi:10.1093/czoolo/61.6.959