Enhancement of information transfer has been proposed as a key driver of the evolution of coloniality. Transfer of information on location of food resources implies that individuals from the same colony share foraging areas and that each colony can be associated to a specific foraging area. In colonial breeding vertebrates, colony-specific foraging areas are often spatially segregated, mitigating intercolony intraspecific competition. By means of simultaneous GPS tracking of lesser kestrels (Falco naumanni) from neighbouring colonies, we showed a clear segregation of space use between individuals from different colonies. Foraging birds from different neighbouring colonies had home ranges that were significantly more segregated in space than expected by chance. This was the case both between large and between small neighbouring colonies. To our knowledge, the lesser kestrel is the only terrestrial species where evidence of spatial segregation of home ranges between conspecifics from neighbouring colonies has been demonstrated. The observed spatial segregation pattern is consistent with the occurrence of public information transfer about foraging areas and with the avoidance of overexploited areas located between neighbouring colonies. Our findings support the idea that spatial segregation of exploited areas may be widespread among colonial avian taxa, irrespective of colony size.

Aim: Migratory animals regularly move between often distant breeding and non-breeding ranges. Knowledge about how these ranges are linked by movements of individuals from different populations is crucial for unravelling temporal variability in population spatial structuring and for identifying environmental drivers of population dynamics acting at different spatio-temporal scales. We performed a large-scale individual-based migration tracking study of the lesser kestrel (Falco naumanni), an Afro-Palearctic migratory raptor, to determine the patterns of migratory connectivity of European breeding populations. Location: Europe, Africa. Methods: Migration data were recorded using different devices (geolocators, Argos PTTs, GPS loggers) from 87 individuals breeding in the three core European populations, located in the Iberian, Italian and Balkan peninsulas. We estimated connectivity by the Mantel correlation coefficient (rM), and computed both the degree of separation between the non-breeding areas of individuals from the same population (i.e. the population spread) and the relative size of the non-breeding range (i.e. the non-breeding range spread). Results: European lesser kestrels migrated on a broad-front across the Mediterranean Sea and Sahara Desert, with different populations using different routes. Iberian birds migrated to western Sahel (Senegal, Mauritania, western Mali), Balkan birds migrated chiefly to central-eastern Sahel (Niger, Nigeria, Chad), whereas Italian ones spread from eastern Mali to Nigeria. Spatial differentiation of non-breeding areas led to a strong migratory connectivity (rM = 0.58), associated with a relatively high population (637 km) and non-breeding range (1149 km) spread. Main conclusions: Our comprehensive analysis of the non-breeding distribution of European lesser kestrel populations revealed a strong migratory connectivity, a rare occurrence in long-distance avian migrants. The geographic conformation of the species' breeding and non-breeding ranges, together with broad-front migration across ecological barriers, promoted the differentiation of migratory routes and non-breeding areas. Strong connectivity could then arise because of both high population spread and broad non-breeding range.