DOI: 10.5061/dryad.c2fqz616r
title: Data from: Strong survival selection on seasonal migration versus residence induced by extreme climatic events

description: 1. Elucidating the full eco-evolutionary consequences of climate change
 requires quantifying the impact of extreme climatic events (ECEs) on
 selective landscapes of key phenotypic traits that mediate responses to
 changing environments. Episodes of strong ECE-induced selection could
 directly alter population composition, and potentially drive
 micro-evolution. However, to date, few studies have quantified ECE-induced
 selection on key traits, meaning that immediate and longer-term
 eco-evolutionary implications cannot yet be considered. 2. One
 widely-expressed trait that allows individuals to respond to changing
 seasonal environments, and directly shapes spatio-seasonal population
 dynamics, is seasonal migration versus residence. Many populations show
 considerable among-individual phenotypic variation, resulting in ‘partial
 migration’. However, variation in the magnitude of direct survival
 selection on migration versus residence has not been rigorously
 quantified, and empirical evidence of whether seasonal ECEs induce,
 intensify, weaken or reverse such selection is lacking. 3. We designed
 full-annual-cycle multi-state capture-recapture models that allow
 estimation of seasonal survival probabilities of migrants and residents
 from spatio-temporally heterogeneous individual resightings. We fitted
 these models to nine years of geographically extensive year-round
 resighting data from partially migratory European shags (Phalacrocorax
 aristotelis). We thereby quantified seasonal and annual survival selection
 on migration versus residence across benign and historically extreme
 non-breeding season (winter) conditions, and tested whether selection
 differed between females and males. 4. We show that two of four observed
 ECEs, defined as severe winter storms causing overall low survival, were
 associated with very strong seasonal survival selection against residence.
 These episodes dwarfed the weak selection or neutrality evident otherwise,
 and hence caused selection through overall annual survival. The ECE that
 caused highest overall mortality and strongest selection also caused
 sex-biased mortality, but there was little overall evidence of sex-biased
 selection on migration versus residence. 5. Our results imply that
 seasonal ECEs and associated mortality can substantially shape the
 landscape of survival selection on migration versus residence. Such
 ECE-induced phenotypic selection will directly alter migrant and resident
 frequencies, and thereby alter immediate spatio-seasonal population
 dynamics. Given underlying additive genetic variation, such ECEs could
 potentially cause micro-evolutionary changes in seasonal migration, and
 thereby cause complex eco-evolutionary population responses to changing
 seasonal environments.
description: This archive contains the dataset, as well as the complete
 posterior samples and detailed numerical summaries of the posterior
 samples for all parameter and derived quantities of the two models
 analysed in the paper. All these components are provided as Rdata
 files alongside "READ ME.txt" files including further
 information on their content. All additional details are available in the
 main text and appendices of the paper.