Data and code from: Ecological and Life-History Correlates of Incubation Attentiveness Differ between Female-Only and Biparentally Incubating Passerine Birds

This dataset includes the file "ATT_data.csv" and "R_code_for_analyses.R".
In ATT_data.csv:
Species: The scientific name of each species.Family: Family name.Daytime_constancy: Daytime nest attentiveness of each study population of each species (%).Amb_temp: Mean ambient temperature during the main incubation months (°C).Longitude: Longitude of each study population.Latitude: Latitude of each study population.IncubationMode: Incubation mode of each species (uni: uniparental; bi: biparental).Ref_Inc_data: References to sources of incubation data.Nest_type: Nest type of each species (grouped cavity and domed nests as enclosed nests).Nest_type_three: Nest type of each species (distinguished cavity and domed nests).Ref_Nest_type: References to sources of nest type data.Body_mass: Adult body mass of each species (g).Ref_Body_mass: References to sources of adult body mass data.Clutch_size: Clutch size of each species.Ref_Clutch_size: References to sources of clutch size data.

MethodsOur incubation data were primarily sourced from four comparative studies that explicitly reported daytime incubation attentiveness or incubation rhythm (mean on- and off-bout durations during daytime, i.e., the time spent on and off the nest), which covered 426 of the total 466 populations (307 species) in our dataset (Matysioková et al. 2011; Matysioková and Remeš 2013; Matysioková and Remeš 2018; Austin et al. 2019). Additional incubation data were supplemented from other published literature identified through searches in Google Scholar and the China National Knowledge Infrastructure (CNKI). Searches used combinations of the keywords “bird” or “avian” with “incubation attentiveness”, “nest attentiveness”, “incubation behaviour”, “incubation rhythm”, “nesting ecology” and “breeding ecology” (with equivalent Chinese keywords used for CNKI searches). Data were available only for female-only incubating species and biparentally incubating species, so our dataset includes only these two incubation modes.
As a proxy for parental incubation investment, daytime incubation attentiveness was calculated as the proportion of total daytime hours that any parent bird spends incubating, which represented the fraction of available time devoted to incubation rather than the absolute total time spent incubating during daytime. Since we aimed to assess the balance between parental incubation and self-maintenance activities (e.g., foraging and rest for maintaining their own condition) (Visser and Lessells 2001; Chalfoun and Martin 2007), this metric is appropriate for interpopulation comparisons.
It should be noted that for female-only incubating species where only incubation rhythm data (i.e., mean on- and off-bout durations) were reported (e.g., data from Matysioková and Remeš 2018), we estimated daytime incubation attentiveness using the formula: [mean on-bout duration / (mean on-bout duration + mean off-bout duration)], following Matysioková and Remeš (2014) who demonstrated a high positive correlation between this estimate and direct incubation attentiveness measurements. However, for biparentally incubating species where both parents usually attend incubation alternatively and thus the average on- and off-bout durations of males and females cannot be used to calculate the daytime incubation attentiveness, only studies that directly reported daytime incubation attentiveness were included.
In addition to the data on incubation attentiveness, we also extracted available data on incubation mode, mean ambient temperature during main incubation months, and study site coordinates for each population from the collected studies. However, some studies did not provide data of mean ambient temperature during the main incubation months (e.g., Matysioková and Remeš 2013). In these cases (in 67 of the total 466 populations in our dataset), we followed the approach of Matysioková and Remeš (2018) to estimate the missing values. To do this, we first extracted the geographic coordinates of the study location from the source literature. If they were not provided, we located the field site on Google Earth and obtained the central coordinates of the region. We then obtained the study year and the primary months of incubation and extracted mean monthly temperatures using the updated CRU TS3.21 climate dataset (0.5° resolution; Harris et al. 2014).
Data on nest structure were primarily obtained from Medina et al. (2022), following their classification of nests into open, domed and cavity types. Given the small sample sizes of biparentally incubating species building domed or cavity nests (Table 1), and their better thermal buffering capacities compared to open nests (Mainwaring et al. 2014; Martin et al. 2017), we first combined domed and cavity nests into a single category (i.e., enclosed nests) for analyses (see below). However, because cavity and domed nests are exposed to different levels of predation risk (Matysioková and Remeš 2022), their effects on incubation behaviours may also differ. We therefore re-ran all the analyses by separating nest structures into open, domed and cavity categories (see also Statistical Analyses section). Data on clutch size and adult body mass were mainly obtained from Székely et al. (2022). Other missing life-history data were supplemented from Birds of the World (birdsoftheworld.org) and other published literature (see our dataset for details).