The COVID-19 lockdowns produced a singular opportunity to perform scientific research in idle cities. The expected changes in urban ecology led us to form a citizen science community which, following standardized protocols, conducted well-structured surveys of birds across Colombia to test questions about urban bird assemblages that had not yet been addressed. Here, we report the process and experience of this citizen science initiative, conducted between March 30 and June 30, 2020, and discuss recommendations to apply to future projects with similar goals. The volunteer-based survey that we organized began with 93 collaborators in 40 urban centers, but ended with just 45 collaborators from 22 urban centers. Some issues that probably explain the drop in collaborators are commented on. This citizen science exercise was successful, gathering over 75,000 bird records of at least 250 bird species.