Large yearly fluctuations in congregation sizes of migratory Danainae butterflies in the Western Ghats, India

We documented the overwintering congregations of migratory Danainae butterflies (Nymphalidae) over six migratory seasons in the threatened tropical forests of the Western Ghats, India. Congregation sizes fluctuated drastically (>90%), indicating vulnerability to chance events. Continued monitoring is needed to explain these fluctuations and identify declining trends for timely conservation action., , # Data from: Large yearly fluctuations in congregation sizes of migratory Danainae butterflies in the Western Ghats, India

Authors: P. A. Vinayan, M. A. Yathumon, Shivani Jadeja

Publication Source and Year: Biotropica, 2025

#### Description:

This dataset contains two data files that can be used to replicate the analysis for Vinayan et al. 2025, Large yearly fluctuations in congregation sizes of migratory Danainae butterflies in the Western Ghats, India. See Methods section of paper Vinayan et al. (2025) for details of sampling.

### 1. Data file name: 20250422\_butterfly\_congregation\_size\_raw\_data.csv

#### Description:

Metadata of raw data file with data on congregation sizes (number of butterflies) collected during the study period. Variable names are described below.

*site - Unique name for each congregation site (Categorical variable)
*lat - Latitude of congregation site, low resolution (Degrees) (Quantitative variable)
*long - Longitude of congregation size, low resol...,