DOI: 10.5061/dryad.pc866t1wc
title: Breeding male Ortolan Bunting observations from Finland 2000-2018

description: Ortolan Bunting male territory observations from Finland from 2000-2018
 and R-code used to analyse the association between population growth rate
 and various environmental and spatial variables. Data includes individual
 identification number for 238 singing groups (id), the year of the
 observation (year), number of observed territories within a singing group
 at the year of the observation (terri), number of observed territories
 during the previous year (terpre), proportion of agricultural land use
 within the singing group landscape (agri5), the mean daily precipitation
 (mm) (prec) and temperature (ºC) (temp) of the previous year summer,
 Shannon-Wiener diversity index of crop types within the singing group area
 (shang), proportion of crop types which provide bare ground in spring
 (bare), density of buildings (build), rivers (river), streams (stream) and
 roads (road), the municipality (municipality) and the region (region)
 where the singing group is located.
description: The territories of the Ortolan Buntings were mapped annually
 using a two-visit mapping method. To form a study unit, we aggregated
 observations of territories from the years 2000–2017 (observations from
 the year 2018 were added in after the forming of singing groups) based on
 their proximity and surrounding landscape. Territories that were less than
 500 metres away from each other, were considered to belong to the same
 singing group, i.e., subpopulation. Then, we drew a 250-meter buffer
 around each territory observation within a singing group, merged the
 overlapping buffers, and interpreted the outline as delineating the area
 occupied by that singing group. Some singing groups were split and merged
 according to field observations and expert opinion. For the statistical
 analysis, we first delimited our data to only those cases that had data
 from two consecutive years, i.e., with no gap between annual observations.
 Then we created a variable describing the number of territories in a
 singing group during the previous year (terpre) and further removed from
 the data those observations, where 'terpre' was zero (no
 territories observed the previous year). From the Finnish topographic
 database provided by the National Land Survey of Finland, we counted the
 length of roads, ditches, main drains, and riverbanks (in metres) and the
 number of buildings within the singing group area. We then divided each of
 these measures by the area of the singing group to form a variable
 describing the density of each small-scale element (road, stream, river,
 building). By combining data from the Finnish land and crop parcel
 registers by the Finnish Food Authority, we counted the total area of crop
 species grown within a singing group area. In cases where crop data were
 untraceable or not available, we completed the data from field notes, when
 possible, otherwise, the crop was classified as an “unknown species”.
 Based on plant type or growth form we classified crop species into ten
 crop types. For each singing group area, we then counted the proportions
 of each of these crop types and based on those, a Shannon–Wiener diversity
 index of crop types (shang). Crop types were further classified into two
 groups based on how much vegetative cover the plants form during the start
 of the Ortolan Bunting breeding season in early May. Crop types that
 provide only minor cover and leave substantial amounts of bare ground on
 the field, mainly as a result of the associated plowing practice, were
 classified as ‘bare’. We counted the proportion of ‘bare’ crop types
 within a singing group area (bare). We created a 5-km buffer around the
 singing group centroid and calculated the proportion of agricultural land
 cover (agri5) within the buffer using the Finnish Corine land cover data
 provided by the Finnish Environment Institute. Lastly, we calculated the
 mean daily temperature (ºC) (temp) and precipitation (mm) (prec) of the
 previous summer (21. May–15. July).  Shaping the data
 for statistical analysis: For the statistical
 analysis, we first delimited our data to only those cases that had data
 from two consecutive years, i.e., with no gap between annual observations.
 Then we created a variable describing the number of territories in a
 singing group during the previous year (terpre) and further removed from
 the data those observations, where terpre was zero (no territories
 observed the previous year).
description: # Breeding male Ortolan Bunting observations from Finland 2000-2018
 [https://doi.org/10.5061/dryad.pc866t1wc](https://doi.org/10.5061/dryad.pc866t1wc) ## Description of the data and file structure The data includes a CSV data table of 678 observations with 15 variables and an R-code used to analyse the association between population growth rate and various environmental and spatial variables. In the data table, each observation (row) corresponds to the findings of one year's territorial mapping within a certain singing group's area. The municipality and region of the singing group are included but the exact coordinates of the locations are shared only on request.  ### Variables * id = singing group * year = year of observation * terri = number of observed territories within a singing group at the year of the observation * terpre = number of observed territories during the previous year * agri5 = proportion of agricultural land use within the singing group landscape * prec = the mean daily precipitation (mm) * temp = the mean daily temperature (ºC) * shang = Shannon-Wiener diversity index of crop types within the singing group area * bare = proportion of crop types which provide bare ground in spring * build = density of buildings * river = density of rivers * stream = density of streams * road = density of roads * municipality = municipality where the singing group is located * region = region where the singing group is located ### Forming of the habitat variables: Data set contains data from the National Land Survey of Finland Topographic Database 08/2017, the Finnish Food Authority field parcel and crop plant registers 08/2017, the Finnish Meteorological Institute Weather Database 08/2019, and the Finnish Environment Institute Corine land cover data set 08/2017. ## Sharing/Access information Field parcel and crop plant registers for the latest year/s are from the Finnish Food Authority Weather data is from the Finnish Meteorological Institute Land use/cover is from the Finnish Environment Institute Topographical data is from the National Land Survey of Finland ## Code/Software The file 'ortolan_code_share.R' is an R-code used for running the statistical analysis performed in the associated manuscript. The code has been created in R, version 4.3.1.