Consistently low extra-pair paternity across two populations of the Chilean Swallow despite their marked latitudinal separation

Abstract

This repository contains the datasets and annotated R scripts generated to investigate extra-pair paternity (EPP) in two breeding populations of the Chilean Swallow (Tachycineta leucopyga) located in Bariloche (Patagonia) and Tierra del Fuego, Argentina. The study aimed to compare EPP rates between populations separated by approximately 14 degrees of latitude and to evaluate whether climatic conditions during the female fertile period were associated with the occurrence of extra-pair paternity.

The datasets were generated from field observations conducted during the 2021–2022 and 2022–2023 breeding seasons in Bariloche and from previously collected data from Tierra del Fuego (2008–2009). Parentage was assigned using SNP genotyping, and climatic variables were extracted from ERA5 reanalysis data. The repository includes datasets used for generalized linear mixed models comparing breeding seasons and populations, as well as datasets used to evaluate associations between climatic variables and the probability of extra-pair paternity.

The repository contains quantitative data, including nest- and chick-level reproductive information, parentage assignments, climatic variables, and fully annotated R scripts reproducing all statistical analyses reported in the associated manuscript. These materials are intended to facilitate transparency, reproducibility, and the reuse of the analytical workflow for future studies on avian reproductive behaviour, behavioural ecology, and the ecological correlates of extra-pair paternity.

All analyses were performed using R version 4.4.0.