DOI: 10.5061/dryad.6hdr7sr83
title: Data from: Ecological tradeoffs drive a power-law relationship between group size and population density in social foragers

description: Foraging animals have been documented forming groups in wide range of
 environments and taxa. Benefits of group foraging include reduced
 predation risk while costs include increased resource competition among
 group members. While the relative strengths of these factors are known to
 vary with density, it is unclear whether forager group sizes should also
 vary with density. Here, we model how the costs and benefits of group
 formation drive density dependence in group size when including the
 impacts of improved vigilance and increased intragroup competition. Our
 model predicts that forager group size will exhibit a one-third power-law
 relationship with their abundance when predator abundance is independent
 of prey abundance. We tested this prediction using empirical data of
 group-foraging birds and ungulates and found clear support for our
 theoretical predictions. Our results contribute to a growing body of work
 highlighting the importance of group formation in maintaining stability in
 predator and prey populations.
description: # Data from: Ecological tradeoffs drive a power-law relationship between
 group size and population density in social foragers
 [https://doi.org/10.5061/dryad.6hdr7sr83](https://doi.org/10.5061/dryad.6hdr7sr83) This data and the associated code will reproduce the analyses in Rouhbakhsh et al. ## Description of the data and file structure **mixedforgs.csv** - data file for running mixed model of group size. Columns are * **N**: Represents the population count or density of the species. - **G**: Indicates the average group size of the species. - **Taxa**: The common name of the species. - **Class**: Indicates whether the species belongs to the "Ungulate" or "Bird" category. - **Data_type**: Specifies whether the data in column **N** represents population density or raw counts ## Code/Software **RegressionCode.R** - code file for running mixed model of group size. Depends on mixedforgs.csv. Reproduces statistical analyses in Rouhbaksh et al. and reproduces Figure 3. **ForagerGroupSize_simulation.R** - code for numerically calculating the optimal group size in a foraging animal population. 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