Data from: Large-scale within-breeding season movements of a long-distance migratory bird, Coccyzus americanus (Yellow-billed Cuckoo)

This dataset includes the data used in analyses for the following publication: Wyman, B. M., C. Q. Stanley, V. Cueto, J. I. Areta, D. Tracy, S. McNeil, and P. P. Marra. 2026. Large-scale within-breeding season movements of a long-distance migratory bird,Coccyzus americanus (Yellow-billed Cuckoo). Ornithology. Abstract: For migratory birds, the breeding season has been viewed as a relatively stationary period due to the high energetic costs involved in reproduction and trade-offs with other life-history events. However, new tracking data suggest that some species of migratory birds make large-scale opportunistic movements within the breeding season. Previous researchers have suspected Coccyzus americanus (Yellow-billed Cuckoo) may be itinerant breeders due to presumed long-distance itinerant movements and irregular breeding behavior based on collections data and field observations. Using movement patterns from a recent tracking study of 71 individuals across their North American breeding range, we tested three hypotheses: (1) C. americanus makes itinerant movements during the breeding season; (2) individuals that move are resource tracking; and (3) movements are associated with an itinerant breeding strategy. We found that ~75% (n = 53/71) of individuals throughout the breeding range made itinerant movements and traveled 965 ± 98 km on average across sites over the course of the breeding season. Females had an average daily step length 2.5 times longer than that of males and stayed at sites for about half as long. Using the Normalized Difference Vegetation Index (NDVI) as a proxy for resource quality, we found that western individuals that moved experienced higher resource quality later in the breeding season and a greater range of NDVI values throughout the breeding season compared to individuals that remained stationary. Overall, individuals upgraded resource quality as they moved between key breeding sites. Lastly, we identified up to 24 individuals (~33% of all individuals tracked) that spent sufficient time at two or more sites to potentially complete successful nesting attempts in each. These results advance our understanding of C. americanus breeding ecology and have important implications for the scale at which population management and conservation decisions are made for this species.