Urban Bird Diversity in Colombia: Insights from Long-Term Studies and Trends for Neotropical megadiverse cities

The significance of biodiversity in urban areas is often overlooked, and there need to be long-term studies to understand how different species respond to these environments. Most information on urban birds comes from short-term studies conducted in the northern hemisphere that can provide insights into the diversity and distribution of communities but may only focus on more visible and abundant species, which can bias them. One of the few global multi-temporal datasets available on urban birds in tropical regions is the Christmas Bird Counts (CBC), conducted in Colombia since 2001. Using CBC data from 21 urban and peri-urban sites in Bogotá, Cali, and MedellÃn between 2001 and 2018, we analyzed the diversity and distribution of bird communities, their response to urbanization and dietary guilds, abundance, similarity, and complementarity. Our results showed that cities and sites with higher levels of urbanization had lower richness, particularly among species that avoid urban areas (called avoiders) and those that rely on a diet of fruits and insects. Peri-urban sites were important in maintaining sensitive species, promoting higher dissimilarity and complementarity. Wetlands and urban parks were crucial for maintaining the highest richness and abundance of avoiders and utilizers in MedellÃn and Bogotá. Long-term studies are necessary to understand bird diversity and distribution patterns in urban areas fully. Our findings provide baseline information to inform decision-making and recommendations for reconciling urban development with preserving native avifauna in megadiverse Neotropical countries like Colombia.