DOI: 10.5061/dryad.87jb3
title: Data from: Multidimensional environmental influences on timing of breeding in a tree swallow population facing climate change

description: Most phenological traits are extremely sensitive to current climate change
 and advances in the timing of important life-history events have been
 observed in many species. In birds, phenotypic plasticity in response to
 temperature is thought to be the main mechanism underlying yearly
 adjustment in the timing of breeding. However, other factors could be
 important and interact to affect the levels of plastic responses between
 and/or within-individuals. Here we use long-term individual-based data on
 Tree swallow (Tachycineta bicolor) to identify the spatial and
 environmental drivers affecting plasticity in laying date and to assess
 their importance at both population and individual levels. We found that
 laying date has advanced by 4.2 days over 10 years, and that it was mainly
 influenced by latitude and an interaction between spring temperature and
 breeder density. Analyses of individual plasticity showed that increases
 in temperature, but not in breeder density, resulted in within-individual
 advances in laying date. Our results suggest that females can adjust their
 laying date as a function of temperature, but that this adjustment will be
 partly constrained in habitats with lower breeder densities. Such
 potential constraint is especially worrying for the broad array of species
 already declining as a result of climate change.
description: Data: determinants of
 laying date at the population levelData used for the
 analysis of the determinants of laying date at the population level, where
 each line represented a farm within a year. Columns included year (YEAR),
 farm identity (FARM), mean laying date (MEAN.LD), (DENSITY; % of occupied
 nest boxes), distance to St-Laurent River (FSL; kilometers); longitude and
 latitude (LONG, LAT; decimal degrees), altitude (ALT; meters), rainfall
 (PREC; milimeters) and temperature (TEMP; Celcius
 degrees).DeterminantPOP.csvData: change between 2 consecutive yearsData used for the first individual plasticity analysis (change between 2 consecutive years), where each line represented a female. Columns included female identity (ID), for the second-year (SY) dataset the change in laying date (SY.dLD), in density (SY.dDENSITY) and in temperature (SY.dTEMP), for the after second-year (ASY) dataset the change in laying date (ASY.dLD), in density (ASY.dDENSITY) and in temperature (ASY.dTEMP), for the total (TOTAL) dataset the change in laying date (TOTAL.dLD), in density (TOTAL.dDENSITY) and in temperature (TOTAL.dTEMP).PlasticityIND1.csvData: random regression analysis with the within-individual centring techniqueData used for the second plasticity analysis (random regression analysis with the within-individual centring technique), where each line represented an individual observation within a year for all females observed at least in two years. Columns included year (YEAR), female identity (ID) and its age (AGE; SY=second-year, ASY=after second-year), farm identity (FARM), laying date (LD; julian days), temperature (TEMPs; std), density (DENSITYs; std) and latitude (LATs; std), between-individual component of temperature (M.TEMP; within individual mean of TEMPs) and density (M.DENSITY; within individual mean of DENSITYs), within-individual component of temperature (TEMP.PLAST; deviation from the individual mean) and density (DENSITY.TEMP; deviation from the individual mean).PlasticityIND2.csv