RT Journal Article T1 How residents behave: home range flexibility and dominance over migrants in a Mediterranean passerine A1 Morganti, Michelangelo A1 Assandri, Giacomo A1 Aguirre De Miguel, José Ignacio A1 Ramírez García, Álvaro A1 Caffi, Mario A1 Pulido Delgado, Francisco AB Residency has repeatedly evolved in many migratory animals, some of which have preserved the anatomical adaptations to perform long-range movements. This is the case for partially migratory populations of Mediterranean passerines in which migrants and residents both have a migrant morphology. The question of how selection maintains residency in this situation remains unclear. Using radiotelemetry, we followed the resident fraction of a partially migratory population of blackcaps, Sylvia atricapilla, from eastern Spain and studied changes in home range size and habitat composition throughout three breeding and two wintering seasons. We then compared these birds with two groups of migratory blackcaps present in the area: in winter with migrants that breed in northern populations and in spring with migrants that breed locally. In addition, we observed aggressive interactions between individually marked birds to explore dominance relationships during winter. The home ranges of resident blackcaps were six times larger in winter than during the breeding season, but within each season, they were comparable in size to those of migrants. The habitats used by residents markedly differed between seasons as well as from those of migrants in winter, but not during the breeding season. In winter, resident birds were dominant over migrants, although migrants were generally larger. Overall, residents showed high between-season flexibility in home range size and habitat use. Winter home ranges of residents included breeding sites and more diverse types of habitats than those of northern migrants. This suggests that in winter, the importance of dominance for obtaining priority access to food may be high but not crucial, given that residents may reduce competition by feeding separately from migrants. Future studies should focus on whether residents show specific personalities and on the role of yearly oscillations in environmental conditions in maintaining residency in this type of partially migratory population. PB Elsevier Masson SN 0003-3472 YR 2017 FD 2017-01 LK https://hdl.handle.net/20.500.14352/17985 UL https://hdl.handle.net/20.500.14352/17985 LA eng NO Ministerio de Ciencia e Innovación (MICINN) NO Ministerio de Educación y Ciencia (MEC) NO University of Milan Bicocca DS Docta Complutense RD 6 abr 2025