DOI: 10.5061/dryad.q3b7b78
title: Data from: Unscrambling variation in avian eggshell colour and patterning in a continent-wide study

description: The evolutionary drivers underlying marked variation in the pigmentation
 of eggs within many avian species remains unclear. The leading hypotheses
 proposed to explain such variation advocate the roles of genetic
 differences, signalling and/or structural integrity. One means of testing
 amongst these hypotheses is to capitalise on museum collections of eggs
 obtained throughout a broad geographic range of a species to ensure
 sufficient variation in predictors pertaining to each hypothesis. Here we
 measured colouration and patterning in eggs from 271 clutches of
 Australian Magpies (Cracticus tibicen) collected across most of their
 geographic range of ca. 7 million km2; encompassing eight subspecies,
 variation in environmental parameters, and the presence/ absence of a
 brood parasite. We found considerable variation in background colour, as
 well as in the extent and distribution of patterning across eggs. There
 was little evidence that this variation was explained by subspecies.
 However, we found marked differences in relation to the contemporary
 presence of a brood parasite. Measures of maximum temperature, relative
 humidity, leaf area index and soil calcium all contributed to variation in
 egg appearance, although their explanatory power was relatively low. Our
 results suggest that multiple factors combine to influence egg appearance
 in this species, and that even in species with highly variable eggs,
 colouration is not readily explained.   Note: An error in data
 manipulation was identified and corrected. A correction has been applied
 to this article (April 2024), approved by RSOS. 
description: Correction Notice: An
 error in data manipulation was identified and corrected. A correction has
 been applied to this article (April 2024), approved by RSOS, and the data
 has been updated to reflect this correction.  
 
 <strong>MagpieCode2024</strong>
 Clean R Code for all Magpie analyses.
 <strong>MagpieCombinedData2024</strong>
 Clean and corrected colour dataset and maculation
 dataset.
 <strong>OutlierDataset2024</strong>
 Outlier dataset.   
description: # Data from: Unscrambling variation in avian eggshell colour and
 patterning in a continent-wide study
 [https://doi.org/10.5061/dryad.q3b7b78](https://doi.org/10.5061/dryad.q3b7b78) ###### Correction Notice: An error in data manipulation was identified and corrected. A correction has been applied to this article (April 2024), approved by RSOS, and the data has been updated to reflect this correction.  ## Description of the data and file structure **MagpieCode2024** Clean R Code for all Magpie analyses (R). **MagpieCombinedData2024** Clean and corrected colour dataset and maculation dataset (csv). **OutlierDataset2024** Outlier dataset (csv).   ## Sharing/Access information Data was derived from the following sources: * Distribution maps were extracted from the Directory of Australian Birds. * Temperatures (Tmax, °C) and relative humidity (%) were downloaded from the Australian Water Availability Project via [http://www.bom.gov.au](http://www.bom.gov.au). * Leaf area index measurements were obtained via the TERN AusCover portal ([http://www.auscover.org.au/](http://www.auscover.org.au/) and produced from tiles originally downloaded from USGS ([https://lpdaac.usgs.gov/](https://lpdaac.usgs.gov/). * Soil calcium levels were extracted from the Soil and Landscape Grid of Australia via [http://www.clw.csiro.au/aclep/soilandlandscapegrid.](http://www.clw.csiro.au/aclep/soilandlandscapegrid.) ## Code/Software R studio code: MagpieCode2024.R Lines 1-139: Data collation Lines 142-154: Start analyses- load MagpieCombinedData2024.csv. Lines 157-329: Univariate analyses Lines 332- 425: Multivariate analyses Lines 430- 510: Figures Lines 513- 585: SM Figures Loaded packages: car, dunn.test, dplyr, EnvStats, ggplot2, lme4, lmerTest, MuMIn, multcomp,pbkrtest, plyr, robCompositions, raster, spdep, tidyr, visreg.