DOI: 10.5061/dryad.qp811
title: Data from: Marked reduction in demographic rates and reduced fitness advantage for early breeding is not linked to reduced thermal matching of breeding time

description: Warmer springs may cause animals to become mistimed if advances of spring
 timing, including available resources, and of timing of breeding occur at
 different speed. We used thermal sums (cumulative sum of degree days)
 during spring to describe the thermal progression (timing) of spring and
 investigate its relationship to breeding phenology and demography of a
 long-distant migrant bird, the northern wheatear (Oenanthe oenanthe L.).
 We first compare 20-year trends in spring timing, breeding time, selection
 for breeding time and annual demographic rates. We then explicitly test
 whether annual variation in selection for breeding time and demographic
 rates associates to the degree of phenological matching between breeding
 time and thermal progression of spring. Both thermal progression of spring
 and breeding time of wheatears advanced in time during the study period.
 But despite breeding on average 7 days earlier with respect to date,
 wheatears bred about 4 days later with respect to thermal spring
 progression. Over the same time period selection for breeding time changed
 from distinct within-season advantage of breeding early to no or very weak
 advantage. Furthermore, demographic rates (nest success, fledgling
 production, recruitment, adult survival) and nestling weight declined
 markedly by 16-79%. Those temporal trends suggest that a reduced degree of
 phenological matching may affect within-season fitness advantage of early
 breeding and population demographic rates. In contrast, when we
 investigate links based on annual variation, we find no significant
 relationship between either demographic rates or fitness advantage of
 early breeding with annual variation in the degree of phenological
 matching. Our results show that corresponding temporal trends in
 phenological matching, selection for breeding time and demographic rates
 are inconclusive evidence for demographic effects of changed phenological
 matching. Instead, we suggest that the trends in selection for breeding
 time and demographic rates are due to a general deterioration of the
 breeding environment.
description: data for breeding
 attempts of northern wheatears with demographic parameters and climatic
 variablesData for breeding
 attempts of northern whetears, Oenanthe oenanthe, including demographic
 parameters (reproduction, survival, nestling weight) and breeding time;
 data have been collected in the field during a long-term population
 monitoring project. Climatic data includede are from weather variables
 collected at the Ultuna Climate Station (59°82’ N, 17°65’ E). The original
 weather variables daily mean temperature and daily rainfall data can be
 retrieved from http://grodden.evp.slu.se/slu_klimat/index.html.
 Information about the variables included in this data file can be found in
 the README file for the whole data set (data set comprises 3 data
 files).breedhat_ECE-2017-02-00166.txtdata on nestlings of northern wheatearsData for ringed and measured nestlings of northern wheatears, Oenanthe oenanthe, including nestling weight, territory and parental covariates, climatic variables and estimates from a linear relationship between nestling weight and within-season breeding time. Climatic data included are from weather variables collected at the Ultuna Climate Station (59°82’ N, 17°65’ E). The original weather variables daily mean temperature and daily rainfall data can be retrieved from http://grodden.evp.slu.se/slu_klimat/index.html. Information about the variables included in this data file can be found in the README file for the whole data set (data set comprises 3 data files).juvW_age567_ECE-2017-02-00166.txtData of annual averages calculated from the original climatic data or breeding dataData of annual averages calculated from the original climatic data or breeding data. Climatic data included are from weather variables collected at the Ultuna Climate Station (59°82’ N, 17°65’ E). The original weather variables daily mean temperature and daily rainfall data can be retrieved from http://grodden.evp.slu.se/slu_klimat/index.html. Breeding data of northern whetears, Oenanthe oenanthe, have been collected in the field during a long-term population monitoring project, and are contained in breedhat_ECE-2017-02-00166.txt, nestling weights are contained in juvW_age567_ECE-2017-02-00166.txt. Information about the variables included in this data file can be found in the README file for the whole data set (data set comprises 3 data files).dates_yr_ECE-2017-02-00166.txtDataSet_ReadMe_ECE-2017-02-00166README file for the data set comprising 3 separate data files (tab delimited text files): breedhat_ECE-2017-02-00166.txt; juvW_age567_ECE-2017-02-00166.txt; dates_yr_ECE-2017-02-00166.txt