This "Zhemchuzhnikov_Versluijs_et_al_2021_readme.txt" file was generated on 2021-02-19 by Tom Versluijs and Misha Zhemchuzhnikov.


GENERAL INFORMATION

1. Title of Dataset: 
A systematic review of long-term avian studies on phenological changes of birds and their food

Abstract:
Many organisms reproduce in seasonal environments, where selection on timing of reproduction is particularly strong as consumers need to synchronize reproduction with the peaked 
occurrence of their food. When a consumer species changes its phenology at a slower rate than its resources, this may induce a trophic mismatch, i.e. offspring growing up after 
the peak in food availability, potentially leading to reductions in growth and survival. However, there is large variation in the degree of trophic mismatches as well as in its 
effects on reproductive output.

Here, we explore the potential causes for variation in the strength of trophic mismatches in published studies of birds. Specifically, we ask whether the changes in the degree of 
mismatch that have occurred over time can be explained by a bird’s (1) breeding latitude, (2) migration distance, and/or (3) life-history traits.

In particular, the script used contains the following analyses: (I) using linear mixed effect models we test whether the rate of change in food phenology, bird phenology and their 
difference (i.e. the rate of change in asynchrony) differed significantly from zero, (II) using linear mixed effect models we test whether the rate of change in asynchrony between 
birds and their food could be explained by breeding latitude, migratory behaviour and/or species life-history traits (body mass, clutch size and incubation duration).

We found that none of these three factors explains changes in the degree of mismatch over time. Nevertheless, food phenology did advance faster at more northerly latitudes, while 
shifts in bird phenology did not show a trend with latitude. We argue that the lack of support in our results is attributable to the large variation in the metrics used to describe 
timing of food availability.

Keywords:
long-term avian studies, trophic mismatch, phenology, life-history traits, migration distance, breeding latitude

2. Author Information
	A. Principal Investigator Contact Information
		Name: Misha (Mikhail) Zhemchuzhnikov
		Institution: NIOZ
		Email: mikhail.zhemchuzhnikov@gmail.com

	B. Associate or Co-investigator Contact Information
		Name: Tom Versluijs
		Institution: NIOZ
		Email: tom.versluijs@gmail.com

3. Date of data collection (single date, range, approximate date): 30 April 2019

4. Data collection: We queried the Web of Science database using the following words and operators in the field TOPIC (search based on title, abstract and key words): (bird* OR avian 
OR ornitholog*) AND (trophic OR phenolog*) AND (*match* OR *synchron* OR shift* OR snowmelt). The asterisk here is used as replacement for any possible combinations of letters. This 
resulted in 910 papers. We subsequently inspected these papers and selected those where food and bird phenology were, following (Visser et al., 2012), measured simultaneously for at 
least 10 years, which has been suggested to be the minimum timespan required to detect trophic mismatches (Miller-Rushing et al., 2010). We excluded several studies from our selection 
because: original estimates of phenological shifts were not reported (Dunn et al., 2011; Visser et al 1998), breeding phenology of birds was indirectly estimated using potentially 
unreliable indicators such as timing of migration or arrival date (Clausen and Clausen 2013; Mayor et al 2017) and studies were conducted in the same area but had partially overlapping 
study periods with studies spanning a longer time period (Both et al 2009; Visser et al 1998). If studies included several bird species, and/or several study sites, we included them 
as separate data points (Bauer et al., 2010; Both et al., 2009; Grabowski, Doyle, Reid, Mossop, & Talarico, 2013; Matthysen, Adriaensen, & Dhondt, 2011; Ross et al., 2017; Saalfeld & 
Lanctot, 2017; Vatka, Rytkönen, & Orell, 2014; Wegge & Rolstad, 2017). Eventually, we used 20 publications with phenological data on 40 populations of 28 bird species and their food.
 
5. Information about funding sources that supported the collection of the data: 
NPP grant from Netherlands Organization for Scientific Research awarded to Jan A. van Gils, Award: ALWPP.2016.044


SHARING/ACCESS INFORMATION

1. Licenses/restrictions placed on the data: 
None

2. Links to publications that cite or use the data: 
DOI: 10.1002/ece3.7346

3. Links to other publicly accessible locations of the data: 
None

4. Links/relationships to ancillary data sets: 
None

5. Was data derived from another source?
No

6. Recommended citation for this dataset:
No recommendation


DATA & FILE OVERVIEW

1. File List:

"Dataset_Zhemchuzhnikov_EcoEvo_2021_02_13.csv": dataset used for analysis

"Analysis_Zhemchuzhnikov_EcoEvo_2021_02_13.R": script used for analysis

"Zhemchuzhnikov_Versluijs_et_al_2021_readme.txt": file with general information and metadata

2. Are there multiple versions of the dataset? 
No


METHODOLOGICAL INFORMATION

1. Description of methods used for collection/generation of data: 
See point 4 under General information.

2. Methods for processing the data: 

(I) Using linear mixed effect models we test whether the rate of change in food phenology ('food_shift'),
bird phenology ('bird_shift') and their difference (i.e. 'dif', the rate of change in asynchrony) differed  
significantly from zero.
(II) Using linear mixed effect models we test whether the rate of change in asynchrony between birds and 
their food ('dif') could be explained by breeding latitude ('latitude'), migratory behaviour ('migration')
and/or a species' life-history traits (body mass; 'mass', clutch size; 'eggs' and incubation duration; 
'incubation'). 

3. Instrument- or software-specific information needed to interpret the data: 
data was analysed in R version 4.0.3.

DATA-SPECIFIC INFORMATION FOR "Dataset_Zhemchuzhnikov_EcoEvo_2021_02_13.csv"

1. Number of variables: 34

2. Number of cases/rows: 40

3. Variable List: 
-species:   name of species
-abb:   abbreviation of species name
-start_breeding_season_month:   start of breeding season according to handbook birds of the World (month)
-mass:   average bodymass of species (gram)
-eggs:   average clutch size of species
-incubation:   average incubation duration of species (days)
-specialization:   food specialization/diet of species
-migration:   migratory behaviour (i.e. is species migratory (M) or resident (R))
-distance:   what is average migratory distance of species (km)
-latitude:   latitude of breeding site (⁰N)
-longitude:   longitude of breeding site
-study_site:   name of study site
-food_shift:   change in phenology of food (days per year)
-food_significant:   was 'food_shift' reported to be significant (reported p-values)
-food_shift_p:   was 'food_shift' reported to be significant (NS or S)
-bird_shift:   change in breeding phenology of bird (days per year)
-bird_significant:   was 'bird_shift' reported to be significant (reported p-values)
-bird_shift_p:   was 'bird_shift' reported to be significant (NS or S)
-dif:   rate of change in asynchrony between birds and food over the study period (days per year), calculated by subtracting food_shift from bird_shift
-reported_dif:   rate of change in asynchrony between birds and food over the study period (days per year) as reported in each study
-dif_significant:   was 'dif' reported to be significant (reported p-values)
-dif_p:   was 'dif' reported to be significant (NS or S)
-fitness:   change in reproductive success over the study period (NO=no, YES+=positive, YES-=negative, NA=unknown)
-fitness_parameters_measured:   which reproductive parameters were measured
-period:   when was the study conducted
-years:   study duration (years)
-absolute_shift:   change in asynchrony between birds and food over the study period (days)
-yardstick:   what event was used to measure food phenology
-method:   how was this 'yardstick' measured/approximated
-event:   what event was used to describe bird breeding phenology
-measure:   what measure was used per event to describe bird breeding phenology
-reference:   study from which data was extracted
-temp_site:   average temperature trend over the study period for the month preceeding the start of the breeding season, untill two months after the start of the breeding season (degrees per decade)
-order:   taxonomic order of species

4. Missing data codes: 
NA: Data was not reported.