When do tropical birds breed? The case of Colombian species assemblages

Understanding when tropical birds breed is key to life-history theory and to predicting how species will respond to environmental change. While early views emphasized the potential for year-round breeding in the tropics, accumulating evidence suggests that reproductive activity in most tropical birds follows some degree of seasonality, often linked to rainfall and associated food pulses. However, large-scale evaluations across ecological gradients remain scarce. Here, we investigated the breeding seasonality of Colombian resident birds using over 80,000 records compiled from bird banding programs and the Global Biodiversity Information Facility (GBIF). These data included birds in breeding condition, active nests, nestlings, and adults displaying reproductive behavior. We asked four main questions: (a) Do Colombian birds exhibit seasonal breeding activity? (b) Does the degree of seasonality vary with latitude and elevation? (c) Are there geographic differences in breeding patterns ..., , # Data from: When do tropical birds breed? The case of Colombian species assemblages

Dataset DOI: [10.5061/dryad.44j0zpcs4](10.5061/dryad.44j0zpcs4)

## Description of the data and file structure

**Dataset Description (Primary database)**

This dataset comprises standardized records of breeding bird observations in Colombia, intended to support analyses of breeding seasonality, geographic patterns, and ecological traits. It consists of a single data table with **218,621 rows** and **12 variables**, covering the period from **1858 to 2021**. A total of **9,568 records** are identified as reproductive, based on the variable `breedingCor = 1`.

**Variables Included**

1. **`species`** *(string)* – Scientific name of the bird species observed.
2. **`day`** *(numeric)* – Day of the month when the observation occurred; may be missing when only month and year are available.
3. **`month`** *(integer)* – Month of observation (1–12).
4. **`year`** *(integer)* – Year of observation (range: 1858–...,