Territoriality and variation in home range size through the entire annual range of migratory great spotted cuckoos (Clamator glandarius)

Supplementary information accompanies this paper at https://doi.org/10.1038/s41598-019-41943-2.We would like to thank Juan José Castro for his help capturing cuckoos in Spain. Marco van der Velde provided excellent support for the lab analyses regarding sex determination of cuckoos. Two anonymous reviewers provided useful comments that helped to improve our manuscript.Variation in home range size throughout the year and its causes are not well understood yet. Migratory brood parasites offer a unique opportunity to incorporate this spatio-temporal dimension into the study of the factors regulating home range dynamics. Using satellite transmitters, we tracked sixteen migratory great spotted cuckoos (Clamator glandarius) of both sexes for up to three years. We constructed home ranges in all major staging areas, from the Spanish breeding areas to the African wintering grounds, analyzed their temporal and geographical variation and investigated their main potential determinants (e.g. food and host availability). We found that home ranges were significantly larger in the breeding area compared to non-breeding areas. Using NDVI as a proxy for food availability, we showed that breeding area home ranges have significantly lower food availability per km2 than home ranges elsewhere which could explain why cuckoos use alternative areas with higher food availability before initiating migration. We also found some evidence for sex differences. Additionally, we found no indications of territoriality in this species, providing novel information into the current debate on brood parasite territoriality. Overall, food availability seems to be an important factor regulating home range dynamics and influencing migratory patterns throughout the year in great spotted cuckoos.This study was partially funded by the Spanish Ministerio de Economía y Competitividad/FEDER (research projects CGL2011-25634/BOS and CGL2017- 89338-P)