This datsaset contains data for a comparison of fledgling activity rates from 9 songbird species in east-central Illinois, USA, described in the paper: "Jones, TM, and MP Ward. 2021. Post-fledging behavioral ecology of migratory songbirds: how do fledgling activity rates vary across species?"; published in Behavioral Ecology. The dataset contains estimates of fledgling activity rates during the daytime, nighttime, and across the post-fledging period, which were compared to estimates of fledgling morphologies (e.g. mass, tarsus, wing development) and post-fledging survival. Analyses, which can be reproduced with this data, showed that overall rates of post-fledging activity differed by species, but species showed similarities in the development of activity rates across the period. All species exhibited a stead increase in activity rates with age and general patterns mirrored rates of post-fledging mortality, including the presence and absence of post-fledging bottlenecks within each species. Additionally, our findings suggest that fledgling wing development and brood size at fledging contribute to variatio in activity rates within and across species.