DOI: 10.5061/dryad.b2rbnzsj2
title: Natal dispersal does not entail survival costs but is linked to breeding dispersal in a migratory shorebird, the southern dunlin Calidris alpina schinzii

description: The costs and benefits of dispersal are often assessed by comparing
 fitness between dispersing and non-dispersing individuals. Importantly,
 individuals that disperse between their natal and first breeding site may
 subsequently be more likely to disperse between breeding sites compared to
 those that remained philopatric to their natal site. Such
 within-individual consistency in dispersal behaviour can bias local
 survival estimation, and thus the survival comparison between dispersing
 and non-dispersing individuals, if breeding dispersal leads to permanent
 emigration from the study area. We examined whether adult survival
 correlates with natal dispersal in a migratory shorebird, the southern
 dunlin (Calidris alpina schinzii), in two isolated patchy populations
 where permanent emigration is expected to be extremely rare. To assess
 whether local adult survival could be biased by non-random breeding
 dispersal, we analysed between-patch breeding dispersal probability and
 quantified within-individual consistency in dispersal. Among females,
 natal dispersers were more likely to disperse again as adults compared to
 non-dispersers, while no difference was observed in males which were
 always highly site faithful. Yet, adult survival did not differ between
 natal dispersing and non-dispersing individuals in either sex. Breeding
 dispersal probability was higher in failed compared to successful
 breeders. Breeding dispersal often resulted in dispersal back to the natal
 patch, i.e. delayed natal philopatry. Our results suggest no survival
 costs of dispersal after first reproduction. Despite individual
 consistency, survival estimates of dispersing individuals were not biased
 because nearly all available breeding habitat was covered. We show that
 consistency in dispersal can occur even in site faithful species like the
 southern dunlin. Studies of the effects of dispersal on survival should
 therefore account for within-individual consistency in dispersal if not
 all available breeding habitat is monitored in open populations. In
 particular, delayed natal philopatry may lead to biased local survival
 estimates for immigrants when compared with philopatric individuals.
description: The data were collected from two breeding populations using
 standard field protocols and colour marking of individuals. These are
 outlined in the article. The dataset is in two parts. The
 capture-recapture data includes encounter histories of individuals and the
 dispersal data includes breeding dispersal information on individuals. The
 data are available are in format ready for analysis in MARK or R. One
 needs to clean the titles that have explanations for the
 variables. This data capture-recapture data collected
 during 1992-2020 from Finnish and Swedish populations of the southern
 dunlin that was used in analysing adult survival differences between
 dispersing and non-dispersing individuals. The grouping on individuals
 include population (Finland/Sweden), dispersal status
 (Dispersing/non-dispersing) and Sex (male/female). The distribution of
 indviduals to these classes is shown below.  The data also include
 information about whether in individual was carrying a geolocator during a
 given year. Did the individual carry a geolocator in a given year? 1= yes,
 0= no 
 
   Finland   Sweden  
 Sex Non-dispersing Dispersing  Non-dispersing  Dispersing Female 35 43 30 10 Male
 45 28 35 13 
 Pakanen VM,
 Koivula K, Doligez B,
 Flodin L-Å, Pauliny A, Rönkä N, Blomqvist D (2022) Natal dispersal does not entail survival costs
 but is linked to breeding dispersal in a migratory shorebird, the southern
 dunlin <em>Calidris alpina schinzii</em>. Oikos, OIK-08951